@import url('https://fonts.googleapis.com/css2?family=IBM+Plex+Mono:wght@400;500;600&family=Noto+Sans+KR:wght@400;500;600;700;800&display=swap');

:root {
  --paper: #f2eddf;
  --paper-deep: #e6decc;
  --paper-light: #faf7ef;
  --ink: #23211b;
  --ink-soft: #665f52;
  --ink-faint: #998f7e;
  --line: #cfc5b2;
  --line-dark: #958b79;
  --green: #285e54;
  --green-light: #dce8df;
  --rust: #bd532b;
  --rust-dark: #87351f;
  --rust-light: #f0d7c8;
  --success: #337451;
  --danger: #963c2f;
  --terminal: #191c19;
  --terminal-ink: #dce4cb;
  --white: #fffdf7;
  --shadow: 0 18px 45px rgba(54, 45, 31, .09);
  --font-body: "Noto Sans KR", "Apple SD Gothic Neo", sans-serif;
  --font-mono: "IBM Plex Mono", "SFMono-Regular", Consolas, monospace;
  --max: 1280px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  min-height: 100vh;
  color: var(--ink);
  background:
    radial-gradient(circle at 20% -10%, rgba(255, 255, 255, .72), transparent 29rem),
    linear-gradient(90deg, rgba(98, 84, 61, .025) 1px, transparent 1px),
    var(--paper);
  background-size: auto, 34px 34px, auto;
  font-family: var(--font-body);
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
}
body::before {
  position: fixed;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  content: "";
  opacity: .22;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 160 160' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='.9' numOctaves='3' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)' opacity='.14'/%3E%3C/svg%3E");
}
a { color: inherit; }
button, input, textarea { font: inherit; }
button, a { -webkit-tap-highlight-color: transparent; }
button { color: inherit; }
:focus-visible { outline: 3px solid rgba(189, 83, 43, .4); outline-offset: 3px; }

.skip-link {
  position: fixed;
  top: 10px;
  left: 10px;
  z-index: 999;
  padding: 10px 16px;
  color: var(--white);
  background: var(--terminal);
  transform: translateY(-150%);
}
.skip-link:focus { transform: translateY(0); }

.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 78px;
  padding: 12px max(24px, calc((100vw - var(--max)) / 2));
  border-bottom: 1px solid var(--line-dark);
  background: rgba(242, 237, 223, .9);
  backdrop-filter: blur(16px);
}
.brand {
  display: inline-flex;
  gap: 13px;
  align-items: center;
  color: var(--ink);
  text-decoration: none;
}
.brand-mark {
  position: relative;
  display: grid;
  width: 34px;
  height: 34px;
  border: 1px solid var(--ink);
  place-items: center;
}
.brand-mark::before,
.brand-mark::after { position: absolute; content: ""; background: var(--rust); }
.brand-mark::before { width: 21px; height: 1px; }
.brand-mark::after { width: 1px; height: 21px; }
.brand-mark i {
  position: absolute;
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: var(--green);
}
.brand-mark i:first-child { top: 5px; left: 5px; }
.brand-mark i:nth-child(2) { right: 5px; bottom: 5px; }
.brand-mark i:last-child { right: 5px; top: 5px; background: var(--rust); }
.brand small,
.brand strong { display: block; line-height: 1.25; }
.brand small { color: var(--ink-soft); font: 500 9px/1.3 var(--font-mono); letter-spacing: .16em; }
.brand strong { margin-top: 3px; font: 600 14px/1.25 var(--font-mono); letter-spacing: .08em; }

.header-gauge {
  display: grid;
  grid-template-columns: auto auto 110px;
  gap: 9px;
  align-items: center;
  color: var(--ink-soft);
  font: 500 10px/1.2 var(--font-mono);
  letter-spacing: .04em;
}
.header-gauge b { color: var(--ink); }
.status-light {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--rust);
  box-shadow: 0 0 0 4px rgba(189, 83, 43, .12), 0 0 11px rgba(189, 83, 43, .6);
}
.gauge-track { height: 5px; overflow: hidden; border: 1px solid var(--line-dark); background: var(--paper-deep); }
.gauge-track i { display: block; width: 0; height: 100%; background: var(--green); transition: width .5s ease; }

main { width: min(var(--max), calc(100% - 48px)); margin: 0 auto; }
.home-hero {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1.55fr) minmax(280px, .75fr);
  gap: clamp(36px, 7vw, 100px);
  align-items: center;
  min-height: 630px;
  padding: 78px clamp(0px, 3vw, 38px) 74px;
  border-bottom: 1px solid var(--line-dark);
}
.ruled-paper::after {
  position: absolute;
  right: 0;
  bottom: -4px;
  left: 0;
  height: 7px;
  content: "";
  background: repeating-linear-gradient(90deg, var(--ink) 0 2px, transparent 2px 9px);
  opacity: .42;
}
.eyebrow, .section-kicker {
  margin: 0 0 18px;
  color: var(--green);
  font: 600 11px/1.4 var(--font-mono);
  letter-spacing: .13em;
  text-transform: uppercase;
}
.eyebrow span {
  display: inline-block;
  margin-right: 5px;
  padding: 4px 8px;
  color: var(--white);
  background: var(--green);
}
.hero-copy h1 {
  max-width: 820px;
  margin: 0;
  font-size: clamp(42px, 5.4vw, 78px);
  font-weight: 800;
  line-height: 1.16;
  letter-spacing: -.055em;
  word-break: keep-all;
}
.hero-copy h1 em {
  position: relative;
  color: var(--rust-dark);
  font-style: normal;
  white-space: nowrap;
}
.hero-copy h1 em::after {
  position: absolute;
  right: 0;
  bottom: -4px;
  left: 0;
  height: 8px;
  content: "";
  background: url("data:image/svg+xml,%3Csvg viewBox='0 0 200 10' xmlns='http://www.w3.org/2000/svg'%3E%3Cpath d='M2 7 Q50 1 99 6 T198 4' fill='none' stroke='%23bd532b' stroke-width='2'/%3E%3C/svg%3E") center/100% 100% no-repeat;
}
.hero-lede { max-width: 720px; margin: 30px 0 0; color: var(--ink-soft); font-size: 17px; word-break: keep-all; }
.hero-lede strong { color: var(--ink); font-weight: 700; }
.hero-actions { display: flex; gap: 24px; align-items: center; margin-top: 34px; }
.button {
  display: inline-flex;
  gap: 20px;
  align-items: center;
  justify-content: center;
  min-height: 50px;
  padding: 0 20px;
  border: 1px solid var(--ink);
  font: 600 13px/1 var(--font-mono);
  letter-spacing: .02em;
  text-decoration: none;
  cursor: pointer;
  transition: transform .18s ease, box-shadow .18s ease, background .18s ease;
}
.button:hover { transform: translate(-2px, -2px); box-shadow: 5px 5px 0 var(--ink); }
.button-primary { color: var(--white); background: var(--rust); }
.button-dark { color: var(--white); background: var(--terminal); }
.button-ghost { background: transparent; }
.button:disabled { color: var(--ink-faint); border-color: var(--line-dark); background: var(--paper-deep); cursor: not-allowed; box-shadow: none; transform: none; }
.text-link { color: var(--green); font: 600 12px/1.4 var(--font-mono); text-underline-offset: 5px; }

.instrument-panel {
  position: relative;
  padding: 36px 30px 30px;
  color: var(--terminal-ink);
  border: 1px solid #090b09;
  background:
    linear-gradient(130deg, rgba(255,255,255,.04), transparent 40%),
    var(--terminal);
  box-shadow: 12px 15px 0 rgba(40, 94, 84, .16), var(--shadow);
}
.panel-screws { position: absolute; inset: 8px; pointer-events: none; }
.panel-screws i { position: absolute; width: 6px; height: 6px; border: 1px solid #5d6259; border-radius: 50%; }
.panel-screws i:nth-child(1) { top: 0; left: 0; }
.panel-screws i:nth-child(2) { top: 0; right: 0; }
.panel-screws i:nth-child(3) { right: 0; bottom: 0; }
.panel-screws i:nth-child(4) { bottom: 0; left: 0; }
.instrument-label { margin-bottom: 26px; color: #88917d; font: 500 10px/1.2 var(--font-mono); letter-spacing: .14em; }
.readout { display: grid; grid-template-columns: 1fr 1fr; align-items: end; padding: 16px 0; border-top: 1px solid #3a4038; }
.readout strong { color: #e8d8a8; font: 400 clamp(52px, 5vw, 74px)/.9 var(--font-mono); letter-spacing: -.08em; text-shadow: 0 0 18px rgba(232, 216, 168, .24); }
.readout span { justify-self: end; color: #9ca58f; font: 500 10px/1.5 var(--font-mono); text-align: right; letter-spacing: .08em; }
.readout.muted strong { color: #60665d; text-shadow: none; }
.telemetry-list { margin: 24px 0 0; padding: 0; border-top: 1px solid #3a4038; }
.telemetry-list div { display: flex; justify-content: space-between; gap: 15px; padding: 10px 0; border-bottom: 1px dashed #3a4038; font: 400 10px/1.5 var(--font-mono); }
.telemetry-list dt { color: #7d8576; }
.telemetry-list dd { margin: 0; text-align: right; }
.online span { display: inline-block; width: 6px; height: 6px; margin-right: 5px; border-radius: 50%; background: #7cc28d; box-shadow: 0 0 8px #7cc28d; }

.course-principle {
  display: grid;
  grid-template-columns: 90px 1fr 1.2fr;
  gap: 32px;
  align-items: center;
  padding: 48px 0;
  border-bottom: 1px solid var(--line-dark);
}
.principle-index { align-self: stretch; color: var(--rust); border-right: 1px solid var(--line-dark); font: 500 22px/1 var(--font-mono); }
.course-principle .section-kicker { margin-bottom: 7px; }
.course-principle h2 { max-width: 450px; margin: 0; font-size: clamp(24px, 3vw, 38px); line-height: 1.32; letter-spacing: -.035em; word-break: keep-all; }
.course-principle > p { margin: 0; color: var(--ink-soft); font-size: 15px; word-break: keep-all; }

.roadmap-section, .method-section { padding: 92px 0; }
.section-heading { display: flex; gap: 36px; align-items: end; justify-content: space-between; margin-bottom: 42px; }
.section-heading .section-kicker { margin-bottom: 8px; }
.section-heading h2 { margin: 0; font-size: clamp(32px, 4vw, 52px); line-height: 1.2; letter-spacing: -.045em; }
.section-heading > p { max-width: 510px; margin: 0 0 4px; color: var(--ink-soft); font-size: 14px; }
.section-heading.compact { align-items: start; }
.roadmap { display: grid; gap: 54px; }
.phase { position: relative; }
.phase::before { position: absolute; top: 36px; bottom: -55px; left: 20px; width: 1px; content: ""; background: var(--line-dark); }
.phase:last-child::before { display: none; }
.phase-header { display: grid; grid-template-columns: 42px 180px 1fr; gap: 18px; align-items: center; margin-bottom: 15px; }
.phase-node { z-index: 1; display: grid; width: 41px; height: 41px; border: 1px solid var(--green); border-radius: 50%; color: var(--green); background: var(--paper); font: 600 11px/1 var(--font-mono); place-items: center; }
.phase-header h3 { margin: 0; font: 600 13px/1.3 var(--font-mono); letter-spacing: .03em; }
.phase-header p { margin: 0; color: var(--ink-soft); font-size: 13px; }
.phase-lessons { display: grid; grid-template-columns: repeat(4, 1fr); gap: 10px; margin-left: 60px; }
.lesson-card {
  position: relative;
  display: flex;
  flex-direction: column;
  min-height: 172px;
  padding: 18px;
  overflow: hidden;
  border: 1px solid var(--line);
  color: var(--ink);
  background: rgba(250, 247, 239, .58);
  text-decoration: none;
  transition: border-color .18s ease, transform .18s ease, background .18s ease;
}
.lesson-card::after { position: absolute; right: -14px; bottom: -20px; color: var(--ink); content: attr(data-day); font: 600 70px/1 var(--font-mono); opacity: .035; }
.lesson-card.available { border-color: var(--rust); background: var(--paper-light); box-shadow: 5px 5px 0 var(--rust-light); }
.lesson-card.available:hover { transform: translateY(-4px); }
.lesson-card.complete { border-color: var(--success); }
.lesson-card .lesson-meta { display: flex; align-items: center; justify-content: space-between; color: var(--ink-faint); font: 500 9px/1 var(--font-mono); letter-spacing: .07em; }
.lesson-status { display: inline-flex; gap: 5px; align-items: center; }
.lesson-status i { width: 6px; height: 6px; border-radius: 50%; background: var(--line-dark); }
.available .lesson-status { color: var(--rust-dark); }
.available .lesson-status i { background: var(--rust); box-shadow: 0 0 8px rgba(189,83,43,.65); }
.complete .lesson-status { color: var(--success); }
.complete .lesson-status i { background: var(--success); }
.lesson-card h4 { margin: 22px 0 8px; font-size: 15px; line-height: 1.5; letter-spacing: -.02em; word-break: keep-all; }
.lesson-card p { margin: auto 0 0; color: var(--ink-soft); font-size: 11px; }

.lesson-preview {
  display: grid;
  grid-template-columns: 140px minmax(0, 1fr) auto;
  gap: 38px;
  align-items: center;
  margin: 22px 0 0;
  padding: 42px;
  color: var(--terminal-ink);
  background: var(--terminal);
  box-shadow: 10px 10px 0 var(--green-light);
}
.preview-number { color: #e8d8a8; font: 400 88px/.9 var(--font-mono); letter-spacing: -.1em; }
.preview-copy .section-kicker { margin-bottom: 7px; color: #9bb7aa; }
.preview-copy h2 { margin: 0 0 12px; color: var(--white); font-size: clamp(25px, 3vw, 38px); line-height: 1.3; letter-spacing: -.03em; }
.preview-copy > p { max-width: 710px; margin: 0; color: #acb2a4; font-size: 14px; }
.preview-features { display: flex; flex-wrap: wrap; gap: 7px; margin: 18px 0 0; padding: 0; list-style: none; }
.preview-features li { padding: 5px 8px; border: 1px solid #4b5248; color: #bec6b5; font: 400 9px/1 var(--font-mono); }
.lesson-preview .button { border-color: #a7ad9f; }

.method-grid { display: grid; grid-template-columns: repeat(4, 1fr); margin: 0; padding: 0; border-top: 1px solid var(--ink); border-left: 1px solid var(--ink); list-style: none; }
.method-grid li { min-height: 230px; padding: 24px; border-right: 1px solid var(--ink); border-bottom: 1px solid var(--ink); }
.method-grid span { color: var(--rust); font: 600 11px/1 var(--font-mono); }
.method-grid h3 { margin: 55px 0 10px; font-size: 20px; }
.method-grid p { margin: 0; color: var(--ink-soft); font-size: 13px; }

.site-footer { display: flex; justify-content: space-between; padding: 26px max(24px, calc((100vw - var(--max)) / 2)); border-top: 1px solid var(--line-dark); color: var(--ink-soft); font: 500 9px/1.4 var(--font-mono); letter-spacing: .08em; }
.toast { position: fixed; right: 24px; bottom: 24px; z-index: 100; max-width: 330px; padding: 13px 16px; color: var(--white); background: var(--terminal); box-shadow: var(--shadow); font-size: 12px; opacity: 0; transform: translateY(12px); transition: opacity .2s, transform .2s; pointer-events: none; }
.toast.show { opacity: 1; transform: translateY(0); }

/* Lesson shell */
.lesson-body { background-size: auto, 28px 28px, auto; }
.lesson-header { position: sticky; top: 0; z-index: 60; display: grid; grid-template-columns: 240px 1fr auto; align-items: center; min-height: 70px; border-bottom: 1px solid var(--line-dark); background: rgba(242, 237, 223, .92); backdrop-filter: blur(15px); }
.lesson-header .brand { padding-left: 22px; }
.lesson-header-center { justify-self: center; color: var(--ink-soft); font: 500 10px/1.3 var(--font-mono); letter-spacing: .08em; }
.lesson-header-actions { display: flex; gap: 8px; padding-right: 18px; }
.icon-button { display: inline-grid; min-width: 38px; height: 38px; padding: 0 10px; border: 1px solid var(--line-dark); background: transparent; cursor: pointer; place-items: center; font: 500 10px/1 var(--font-mono); }
.icon-button:hover { background: var(--paper-light); }
.mobile-course-toggle { display: none; }

.lesson-shell { display: grid; grid-template-columns: 240px minmax(0, 920px) 230px; justify-content: center; max-width: 1440px; margin: 0 auto; }
.course-rail, .notes-rail { position: sticky; top: 70px; align-self: start; height: calc(100vh - 70px); overflow-y: auto; scrollbar-width: thin; }
.course-rail { padding: 25px 18px 50px 22px; border-right: 1px solid var(--line); background: rgba(230, 222, 204, .18); }
.notes-rail { padding: 25px 22px 50px 18px; border-left: 1px solid var(--line); background: rgba(230, 222, 204, .13); }
.rail-label { display: flex; align-items: center; justify-content: space-between; margin: 0 0 16px; color: var(--ink-faint); font: 600 9px/1.3 var(--font-mono); letter-spacing: .1em; }
.course-list { display: grid; gap: 3px; margin: 0; padding: 0; list-style: none; }
.course-list li { min-width: 0; }
.course-link { position: relative; display: grid; grid-template-columns: 32px 1fr auto; gap: 8px; align-items: center; width: 100%; min-height: 46px; padding: 7px 8px; border: 0; color: var(--ink-soft); background: transparent; text-align: left; text-decoration: none; }
.course-link::before { position: absolute; top: 6px; bottom: 6px; left: -10px; width: 2px; content: ""; background: transparent; }
.course-link[aria-current="page"] { color: var(--ink); background: var(--paper-light); }
.course-link[aria-current="page"]::before { background: var(--rust); }
.course-link:not(.locked):hover { background: var(--paper-light); }
.course-link.locked { color: var(--ink-faint); cursor: not-allowed; opacity: .72; }
.course-day { font: 600 10px/1 var(--font-mono); }
.course-title { overflow: hidden; font-size: 11px; line-height: 1.35; text-overflow: ellipsis; white-space: nowrap; }
.course-state { color: var(--line-dark); font: 600 9px/1 var(--font-mono); }
.course-link[aria-current="page"] .course-state { color: var(--rust); }
.rail-progress { margin-top: 25px; padding-top: 18px; border-top: 1px dashed var(--line-dark); }
.rail-progress-label { display: flex; justify-content: space-between; color: var(--ink-soft); font: 500 9px/1.2 var(--font-mono); }
.rail-progress .gauge-track { margin-top: 9px; }

.lesson-main { min-width: 0; padding: 54px clamp(30px, 4vw, 60px) 110px; }
.lesson-hero { padding-bottom: 52px; border-bottom: 1px solid var(--ink); }
.lesson-hero-meta { display: flex; gap: 8px; flex-wrap: wrap; margin-bottom: 24px; }
.label-chip { padding: 5px 8px; border: 1px solid var(--line-dark); color: var(--ink-soft); font: 500 9px/1 var(--font-mono); letter-spacing: .05em; }
.label-chip.hot { color: var(--rust-dark); border-color: var(--rust); background: var(--rust-light); }
.label-chip.hot.complete { color: var(--success); border-color: var(--success); background: var(--green-light); }
.lesson-hero h1 { max-width: 750px; margin: 0; font-size: clamp(42px, 5.3vw, 68px); font-weight: 800; line-height: 1.16; letter-spacing: -.055em; word-break: keep-all; }
.lesson-hero .lead { max-width: 680px; margin: 25px 0 0; color: var(--ink-soft); font-size: 17px; word-break: keep-all; }
.completion-spec { display: grid; grid-template-columns: 1fr 1fr; gap: 18px; margin-top: 34px; padding: 22px; border: 1px solid var(--line-dark); background: rgba(250,247,239,.5); }
.completion-spec h2 { margin: 0 0 9px; font: 600 11px/1.3 var(--font-mono); letter-spacing: .08em; }
.completion-spec p, .completion-spec ul { margin: 0; color: var(--ink-soft); font-size: 12px; }
.completion-spec ul { padding-left: 18px; }

.lesson-section { padding: 62px 0; border-bottom: 1px solid var(--line); scroll-margin-top: 96px; }
.lesson-section:last-child { border-bottom: 0; }
.section-number { display: flex; gap: 10px; align-items: center; margin: 0 0 12px; color: var(--rust); font: 600 10px/1 var(--font-mono); letter-spacing: .09em; }
.section-number::after { width: 55px; height: 1px; content: ""; background: var(--rust); }
.lesson-section > h2 { max-width: 700px; margin: 0 0 20px; font-size: clamp(29px, 3.5vw, 42px); line-height: 1.27; letter-spacing: -.04em; word-break: keep-all; }
.lesson-section > h3 { margin: 34px 0 10px; font-size: 20px; }
.lesson-section > p, .prose p { margin: 0 0 18px; color: var(--ink-soft); font-size: 15px; word-break: keep-all; }
.lesson-section strong { color: var(--ink); }
.lesson-section code { padding: 2px 5px; border: 1px solid var(--line); background: var(--paper-light); font: 500 .88em/1.4 var(--font-mono); }

.checklist { display: grid; gap: 8px; margin: 28px 0; padding: 0; list-style: none; }
.check-row { position: relative; display: grid; grid-template-columns: auto 1fr auto; gap: 13px; align-items: start; padding: 16px; border: 1px solid var(--line); background: rgba(250,247,239,.48); cursor: pointer; }
.check-row:hover { border-color: var(--line-dark); }
.check-row input { position: absolute; opacity: 0; }
.mechanical-check { display: grid; width: 24px; height: 24px; border: 1px solid var(--ink); background: var(--paper-light); place-items: center; }
.mechanical-check::after { content: ""; width: 10px; height: 6px; border-bottom: 2px solid var(--white); border-left: 2px solid var(--white); opacity: 0; transform: rotate(-45deg) translate(1px,-1px); }
.check-row input:checked + .mechanical-check { background: var(--success); }
.check-row input:checked + .mechanical-check::after { opacity: 1; }
.check-row input:focus-visible + .mechanical-check { outline: 3px solid rgba(189,83,43,.4); outline-offset: 3px; }
.check-copy strong { display: block; font-size: 13px; }
.check-copy small { display: block; margin-top: 3px; color: var(--ink-soft); font-size: 11px; }
.done-stamp { align-self: center; padding: 4px 7px; border: 1px solid var(--line); color: var(--ink-faint); font: 600 9px/1 var(--font-mono); transform: rotate(-3deg); }
.check-row:has(input:checked) .done-stamp { color: var(--success); border-color: var(--success); }
.worksheet { margin-top: 28px; border: 1px solid var(--ink); background: var(--paper-light); }
.worksheet-header { display: flex; justify-content: space-between; padding: 12px 16px; border-bottom: 1px solid var(--ink); color: var(--paper-light); background: var(--green); font: 500 10px/1.3 var(--font-mono); }
.worksheet-body { padding: 24px; }
.worksheet-row { display: grid; grid-template-columns: 170px 1fr; gap: 20px; padding: 14px 0; border-bottom: 1px dashed var(--line); }
.worksheet-row:last-child { border-bottom: 0; }
.worksheet-row label { color: var(--ink-soft); font: 600 10px/1.5 var(--font-mono); }
.worksheet-row textarea, .worksheet-row input { width: 100%; min-height: 38px; padding: 6px 9px; border: 0; border-bottom: 1px solid var(--line-dark); color: var(--ink); background: transparent; resize: vertical; }
.worksheet-row textarea { min-height: 72px; }
.save-state { color: var(--success); }

.quiz { display: grid; gap: 16px; margin-top: 28px; }
.quiz-question { margin: 0; padding: 22px; border: 1px solid var(--line-dark); background: rgba(250,247,239,.5); }
.quiz-question legend { width: 100%; padding: 0 0 13px; font-size: 14px; font-weight: 700; }
.quiz-number { margin-right: 7px; color: var(--rust); font: 600 10px/1 var(--font-mono); }
.quiz-options { display: grid; gap: 7px; }
.quiz-option { display: grid; grid-template-columns: auto 1fr; gap: 10px; align-items: start; padding: 10px 12px; border: 1px solid var(--line); background: var(--paper-light); cursor: pointer; font-size: 12px; }
.quiz-option:hover { border-color: var(--green); }
.quiz-option input { margin-top: 5px; accent-color: var(--green); }
.quiz-option.correct { border-color: var(--success); background: var(--green-light); }
.quiz-option.incorrect { border-color: var(--danger); background: var(--rust-light); }
.quiz-feedback { display: none; margin: 12px 0 0; padding: 10px 12px; border-left: 3px solid var(--green); color: var(--ink-soft); background: var(--paper-deep); font-size: 11px; }
.quiz-feedback.visible { display: block; }
.quiz-feedback.wrong { border-color: var(--danger); }
.quiz-scorecard { display: flex; gap: 20px; align-items: center; justify-content: space-between; padding: 20px; color: var(--terminal-ink); background: var(--terminal); }
.quiz-scorecard strong { color: #e8d8a8; font: 500 32px/1 var(--font-mono); }
.quiz-scorecard span { color: #aab2a0; font-size: 11px; }

.completion-panel { display: grid; grid-template-columns: 1fr auto; gap: 30px; align-items: center; padding: 30px; border: 1px solid var(--green); background: var(--green-light); }
.completion-panel h2 { margin: 0 0 8px; font-size: 23px; }
.completion-panel p { margin: 0; color: var(--ink-soft); font-size: 12px; }
.completion-panel .button { white-space: nowrap; }
.lesson-complete .completion-panel { position: relative; }
.lesson-complete .completion-panel::after { position: absolute; top: 11px; right: 13px; padding: 4px 7px; border: 1px solid var(--success); color: var(--success); content: "완료"; font: 600 8px/1 var(--font-mono); letter-spacing: .08em; transform: rotate(2deg); }

.source-list { margin: 25px 0 0; padding: 0; list-style: none; }
.source-list li { padding: 13px 0; border-bottom: 1px dashed var(--line); }
.source-list a { color: var(--green); font-size: 13px; font-weight: 600; text-underline-offset: 4px; }
.source-list small { display: block; color: var(--ink-soft); font-size: 10px; }

.notes-card { margin-bottom: 18px; padding-bottom: 18px; border-bottom: 1px dashed var(--line-dark); }
.notes-card h2 { margin: 0 0 10px; font: 600 10px/1.3 var(--font-mono); letter-spacing: .08em; }
.notes-card p { margin: 0; color: var(--ink-soft); font-size: 11px; }
.section-toc { display: grid; gap: 2px; margin: 0; padding: 0; list-style: none; }
.section-toc a { display: block; padding: 6px 8px; color: var(--ink-soft); font-size: 10px; text-decoration: none; }
.section-toc a:hover, .section-toc a.active { color: var(--rust-dark); background: var(--rust-light); }
.quick-note { width: 100%; min-height: 145px; padding: 10px; border: 1px solid var(--line); color: var(--ink); background: rgba(250,247,239,.65); resize: vertical; font-size: 11px; }

/* Day 1: visual learning stations */
.visual-lesson .lesson-main { overflow: hidden; }
.lesson-hero-visual { position: relative; }
.lesson-hero-visual::after {
  position: absolute;
  top: 4px;
  right: -35px;
  width: 180px;
  height: 180px;
  border: 1px solid var(--line);
  border-radius: 50%;
  content: "";
  box-shadow: inset 0 0 0 28px var(--paper), inset 0 0 0 29px var(--line), inset 0 0 0 58px var(--paper), inset 0 0 0 59px var(--line);
  opacity: .45;
}
.hero-question { position: relative; z-index: 1; margin: 0 0 9px; color: var(--green); font: 600 12px/1.4 var(--font-mono); }
.lesson-hero-visual h1 { position: relative; z-index: 1; max-width: 800px; font-size: clamp(43px, 5vw, 70px); }
.lesson-hero-visual h1 em { color: var(--rust-dark); font-style: normal; }
.lesson-hero-visual .lead { max-width: 720px; }
.visual-summary { position: relative; z-index: 2; display: grid; grid-template-columns: repeat(5, 1fr); gap: 0; margin: 38px 0 0; padding: 0; border: 1px solid var(--ink); background: var(--paper-light); list-style: none; }
.visual-summary li { position: relative; min-width: 0; min-height: 150px; padding: 18px 13px 15px; border-right: 1px solid var(--ink); }
.visual-summary li:last-child { border-right: 0; }
.visual-summary li:not(:last-child)::after { position: absolute; top: 40px; right: -7px; z-index: 2; display: grid; width: 14px; height: 14px; border: 1px solid var(--ink); border-radius: 50%; content: "›"; background: var(--paper-light); font: 600 11px/1 var(--font-mono); place-items: center; }
.visual-summary b, .visual-summary small { display: block; }
.visual-summary b { margin-top: 17px; font-size: 12px; }
.visual-summary small { margin-top: 3px; color: var(--ink-soft); font-size: 9px; line-height: 1.45; }
.summary-icon { position: relative; display: block; width: 38px; height: 38px; color: var(--green); }
.model-icon { border: 2px solid currentColor; border-radius: 50%; }
.model-icon::before, .model-icon::after { position: absolute; border-radius: 50%; content: ""; background: currentColor; }
.model-icon::before { top: 9px; left: 10px; width: 4px; height: 4px; box-shadow: 12px 0 currentColor; }
.model-icon::after { bottom: 8px; left: 9px; width: 16px; height: 7px; border-radius: 8px 8px 3px 3px; }
.data-icon { border: 2px solid currentColor; }
.data-icon::before { position: absolute; inset: 7px; border-top: 2px solid currentColor; border-bottom: 2px solid currentColor; content: ""; }
.format-icon::before, .format-icon::after { position: absolute; top: 3px; width: 14px; height: 30px; border: 2px solid currentColor; content: ""; }
.format-icon::before { left: 0; border-right: 0; }
.format-icon::after { right: 0; border-left: 0; }
.train-icon { border: 2px dashed currentColor; border-radius: 50%; }
.train-icon::before { position: absolute; inset: 11px; border-radius: 50%; content: ""; background: var(--rust); }
.file-icon { border: 2px solid currentColor; border-radius: 2px; }
.file-icon::before { position: absolute; top: -2px; right: -2px; width: 13px; height: 13px; border-bottom: 2px solid currentColor; border-left: 2px solid currentColor; content: ""; background: var(--paper-light); }
.compact-spec { margin-top: 22px; }

.learning-station { padding: 70px 0; }
.station-heading { display: grid; grid-template-columns: minmax(0, 1.4fr) minmax(220px, .7fr); gap: 32px; align-items: end; margin-bottom: 30px; }
.station-heading .section-number { margin-bottom: 12px; }
.station-heading h2 { margin: 0; font-size: clamp(30px, 3.5vw, 44px); line-height: 1.23; letter-spacing: -.045em; word-break: keep-all; }
.station-heading > p { margin: 0 0 4px; color: var(--ink-soft); font-size: 12px; }
.section-brief { display: grid; grid-template-columns: repeat(3, 1fr); margin: -8px 0 28px; padding: 0; border: 1px solid var(--line-dark); background: var(--paper-light); list-style: none; }
.section-brief li { min-width: 0; padding: 15px 16px 16px; border-right: 1px solid var(--line); }
.section-brief li:last-child { border-right: 0; }
.section-brief b, .section-brief span { display: block; }
.section-brief b { margin-bottom: 7px; color: var(--green); font: 600 10px/1.3 var(--font-mono); }
.section-brief span { color: var(--ink-soft); font-size: 10px; line-height: 1.65; word-break: keep-all; }
.section-brief code { padding: 0; border: 0; background: transparent; font-size: .88em; overflow-wrap: anywhere; }
.finish-section > .section-brief { margin-top: 25px; }

.prompt-selector { display: flex; flex-wrap: wrap; gap: 7px; }
.prompt-chip { padding: 9px 12px; border: 1px solid var(--line-dark); color: var(--ink-soft); background: transparent; cursor: pointer; font-size: 11px; }
.prompt-chip:hover, .prompt-chip.active { color: var(--white); border-color: var(--green); background: var(--green); }
.selected-prompt { display: flex; gap: 18px; align-items: center; margin: 14px 0 18px; padding: 13px 16px; border-left: 4px solid var(--rust); background: var(--paper-deep); }
.selected-prompt span { flex: 0 0 auto; color: var(--ink-soft); font: 600 9px/1 var(--font-mono); }
.selected-prompt strong { font-size: 13px; }
.model-comparison { position: relative; display: grid; grid-template-columns: 1fr 1fr; gap: 13px; }
.model-output { min-width: 0; overflow: hidden; border: 1px solid var(--ink); background: var(--paper-light); }
.model-output > header { display: flex; gap: 11px; align-items: center; padding: 15px 16px; border-bottom: 1px solid var(--line-dark); }
.model-output header div { min-width: 0; }
.model-output header b, .model-output header code { display: block; }
.model-output header b { font-size: 13px; }
.model-output header code { margin-top: 3px; overflow: hidden; color: var(--ink-soft); background: none; font-size: 9px; text-overflow: ellipsis; white-space: nowrap; }
.model-dot { width: 12px; height: 12px; border: 1px solid var(--ink); border-radius: 50%; background: var(--line); }
.it-output .model-dot { border-color: var(--green); background: var(--green); box-shadow: 0 0 0 5px var(--green-light); }
.output-bubble { min-height: 172px; padding: 24px 20px; }
.output-label { display: inline-block; padding: 4px 6px; color: var(--ink-soft); border: 1px solid var(--line); font: 500 8px/1 var(--font-mono); }
.output-bubble p { margin: 19px 0 0; color: var(--ink); font-size: 15px; line-height: 1.8; }
.model-output footer { min-height: 48px; padding: 11px 16px; color: var(--ink-soft); border-top: 1px dashed var(--line); font-size: 10px; }
.it-output { border-color: var(--green); box-shadow: inset 0 4px 0 var(--green); }
.compare-mark { position: absolute; top: 50%; left: 50%; z-index: 3; display: grid; width: 38px; height: 38px; color: var(--white); border-radius: 50%; background: var(--rust); font: 600 9px/1 var(--font-mono); place-items: center; transform: translate(-50%, -50%); }
.model-id-note { display: grid; grid-template-columns: auto 1fr; gap: 13px; align-items: center; margin: 16px 0; padding: 14px 16px; border: 1px solid var(--line-dark); }
.note-symbol { display: grid; width: 27px; height: 27px; color: var(--rust-dark); border: 1px solid var(--rust); border-radius: 50%; font: 600 11px/1 var(--font-mono); place-items: center; }
.model-id-note p { margin: 0; color: var(--ink-soft); font-size: 11px; }

.station-check { margin-top: 18px; border-color: var(--green); background: var(--green-light); }
.station-check .done-stamp { border-color: var(--green); color: var(--green); }
.inline-checks { display: grid; grid-template-columns: 1fr 1fr; gap: 8px; }
.inline-checks .station-check { height: calc(100% - 18px); }

.two-axis-explainer { display: grid; grid-template-columns: 1fr 36px 1fr; gap: 10px; align-items: stretch; margin-bottom: 16px; }
.axis-card { padding: 20px; color: var(--white); background: var(--green); }
.axis-card.selectable { color: var(--ink); border: 1px solid var(--ink); background: var(--paper-light); }
.axis-card > span { display: block; margin-bottom: 12px; font: 500 9px/1 var(--font-mono); opacity: .75; }
.axis-card strong { display: block; font: 600 22px/1.2 var(--font-mono); }
.axis-card p { margin: 10px 0 0; font-size: 11px; opacity: .82; }
.axis-plus { display: grid; color: var(--rust); font: 400 28px/1 var(--font-mono); place-items: center; }
.method-lab { display: grid; grid-template-columns: 1fr 1fr; border: 1px solid var(--ink); background: var(--paper-light); }
.method-controls { padding: 24px; border-right: 1px solid var(--ink); }
.control-label { margin: 0 0 10px; color: var(--ink-soft); font: 600 9px/1 var(--font-mono); }
.method-buttons { display: grid; grid-template-columns: repeat(3, 1fr); gap: 5px; }
.method-buttons button { min-height: 40px; border: 1px solid var(--line-dark); background: transparent; cursor: pointer; font: 600 12px/1 var(--font-mono); }
.method-buttons button:hover, .method-buttons button.active { color: var(--white); border-color: var(--rust); background: var(--rust); }
.method-copy { min-height: 120px; padding-top: 25px; }
.method-badge { display: inline-block; padding: 5px 7px; color: var(--green); border: 1px solid var(--green); font: 600 10px/1 var(--font-mono); }
.method-copy p { margin: 12px 0 0; color: var(--ink-soft); font-size: 12px; }
.method-metrics { margin: 0; border-top: 1px dashed var(--line-dark); }
.method-metrics div { display: grid; grid-template-columns: 130px 1fr; gap: 12px; align-items: center; padding: 11px 0; border-bottom: 1px dashed var(--line); }
.method-metrics dt { color: var(--ink-soft); font-size: 10px; }
.method-metrics dt small { display: block; margin-top: 2px; color: var(--ink-faint); font-size: 8px; }
.method-metrics dd { margin: 0; font-size: 11px; font-weight: 700; }
.metric-track { display: block; width: 100%; height: 9px; border: 1px solid var(--line-dark); background: var(--paper-deep); }
.metric-track i { display: block; height: 100%; min-width: 38px; padding: 0 4px; color: var(--white); background: var(--rust); font: 600 7px/8px var(--font-mono); text-align: right; white-space: nowrap; transition: width .3s ease; }
.weight-visual { display: grid; align-content: center; padding: 24px; background: var(--paper-deep); }
.weight-caption { display: flex; justify-content: space-between; margin-bottom: 14px; font: 500 9px/1 var(--font-mono); }
.legend { color: var(--ink-soft); }
.legend i { display: inline-block; width: 7px; height: 7px; margin: 0 3px 0 7px; border: 1px solid var(--line-dark); }
.legend i:first-child { background: var(--rust); }
.weight-grid { display: grid; grid-template-columns: repeat(8, 1fr); gap: 5px; aspect-ratio: 1.7; }
.weight-grid i { border: 1px solid var(--line-dark); background: var(--paper-light); transition: background .25s, border-color .25s, opacity .25s; }
.weight-grid.method-fft i { border-color: var(--rust); background: var(--rust); }
.weight-grid.method-lora i:nth-child(8n + 2), .weight-grid.method-lora i:nth-child(8n + 6) { border-color: var(--rust); background: var(--rust); }
.weight-grid.method-qlora i { background: repeating-linear-gradient(135deg, #b4aa98 0 3px, var(--paper-light) 3px 6px); opacity: .72; }
.weight-grid.method-qlora i:nth-child(8n + 2), .weight-grid.method-qlora i:nth-child(8n + 6) { border-color: var(--rust); background: var(--rust); opacity: 1; }
.weight-hint { margin: 12px 0 0; color: var(--ink-soft); font-size: 9px; }

.template-demo { display: grid; grid-template-columns: 1fr 90px 1fr; align-items: stretch; }
.template-panel { min-width: 0; overflow: hidden; border: 1px solid var(--ink); background: var(--paper-light); }
.template-panel header { display: flex; justify-content: space-between; gap: 12px; padding: 12px 14px; color: var(--white); background: var(--terminal); font-size: 10px; }
.template-panel header code { color: #aab2a0; border: 0; background: none; font-size: 8px; }
.template-panel pre { min-height: 190px; margin: 0; padding: 20px; overflow: auto; color: var(--ink); font: 11px/1.7 var(--font-mono); white-space: pre-wrap; }
.template-panel pre b { color: var(--rust-dark); }
.template-panel ul { display: flex; gap: 15px; margin: 0; padding: 12px 15px; border-top: 1px dashed var(--line); list-style: none; }
.template-panel li { color: var(--ink-soft); font-size: 9px; }
.template-panel li i { display: inline-block; width: 7px; height: 7px; margin-right: 5px; border-radius: 50%; background: var(--rust); }
.template-panel li i.role-assistant { background: var(--green); }
.transform-button { align-self: center; display: grid; gap: 8px; justify-items: center; min-height: 92px; padding: 12px 6px; border: 0; color: var(--white); background: var(--rust); cursor: pointer; font: 600 9px/1.3 var(--font-mono); }
.transform-button i { font-size: 21px; font-style: normal; }
.transform-button:hover { background: var(--rust-dark); }
.model-view { background: var(--terminal); }
.model-view .template-placeholder { display: grid; min-height: 250px; padding: 22px; color: #8d9687; place-content: center; text-align: center; }
.template-placeholder span, .template-placeholder strong { display: block; }
.template-placeholder span { font: 500 9px/1 var(--font-mono); }
.template-placeholder strong { margin-top: 10px; color: var(--terminal-ink); font-size: 12px; }
.model-view .template-result { display: none; min-height: 250px; color: var(--terminal-ink); background: var(--terminal); }
.template-result mark { display: inline-block; margin-bottom: 4px; padding: 3px 5px; color: var(--terminal); background: #e8d8a8; font: 600 8px/1 var(--font-mono); }
.template-result mark.assistant-token { background: #95c1a8; }
.template-result mark.boundary-token { color: var(--terminal-ink); border: 1px solid #697064; background: transparent; }
.template-demo.is-transformed .template-placeholder { display: none; }
.template-demo.is-transformed .template-result { display: block; }
.template-status { margin: 11px 0 0; color: var(--ink-soft); font-size: 10px; text-align: right; }
.template-demo.is-transformed + .template-status { color: var(--success); }
.template-rules { display: grid; grid-template-columns: repeat(3, 1fr); margin-top: 18px; border: 1px solid var(--line-dark); }
.template-rules div { padding: 16px; border-right: 1px solid var(--line-dark); }
.template-rules div:last-child { border-right: 0; }
.template-rules span, .template-rules b, .template-rules small { display: block; }
.template-rules span { color: var(--rust); font: 600 9px/1 var(--font-mono); }
.template-rules b { margin-top: 16px; font-size: 12px; }
.template-rules small { margin-top: 3px; color: var(--ink-soft); font-size: 9px; }

.term-deck { display: grid; grid-template-columns: repeat(5, 1fr); gap: 8px; }
.term-card-v2 { min-width: 0; height: 145px; padding: 0; border: 0; background: transparent; cursor: pointer; perspective: 800px; }
.term-inner { position: relative; display: block; width: 100%; height: 100%; transition: transform .42s ease; transform-style: preserve-3d; }
.term-card-v2.is-flipped .term-inner { transform: rotateY(180deg); }
.term-front, .term-back { position: absolute; inset: 0; display: flex; flex-direction: column; justify-content: space-between; padding: 15px; border: 1px solid var(--line-dark); background: var(--paper-light); backface-visibility: hidden; }
.term-front small { color: var(--rust); font: 600 8px/1 var(--font-mono); }
.term-front b { overflow-wrap: anywhere; font: 600 clamp(12px, 1.3vw, 16px)/1.25 var(--font-mono); }
.term-front em { color: var(--ink-soft); font-size: 9px; font-style: normal; }
.term-back { color: var(--white); background: var(--green); transform: rotateY(180deg); }
.term-back b { font-size: 12px; }
.term-back > span { font-size: 10px; line-height: 1.55; }
.term-back small { color: #c6d9d0; font-size: 8px; }
.term-card-v2:hover .term-front { border-color: var(--green); box-shadow: 3px 3px 0 var(--green-light); }
.flow-strip { display: flex; gap: 8px; align-items: center; justify-content: space-between; margin-top: 20px; padding: 14px; overflow-x: auto; color: var(--ink-soft); border: 1px solid var(--ink); background: var(--paper-deep); white-space: nowrap; }
.flow-strip span { display: inline-flex; gap: 6px; align-items: center; font-size: 10px; }
.flow-strip span b { display: grid; width: 20px; height: 20px; color: var(--white); border-radius: 50%; background: var(--green); font: 600 8px/1 var(--font-mono); place-items: center; }
.flow-strip > i { color: var(--rust); font-style: normal; }

.safety-lab { display: grid; grid-template-columns: 1fr 1fr; border: 1px solid var(--ink); }
.scenario-list { display: grid; padding: 8px; border-right: 1px solid var(--ink); background: var(--paper-deep); }
.scenario-list button { display: grid; gap: 5px; align-content: center; min-height: 96px; padding: 14px; border: 1px solid transparent; border-bottom-color: var(--line); background: transparent; text-align: left; cursor: pointer; }
.scenario-list button:last-child { border-bottom-color: transparent; }
.scenario-list button:hover, .scenario-list button.active { border-color: var(--rust); background: var(--paper-light); box-shadow: inset 4px 0 0 var(--rust); }
.scenario-list button span { color: var(--rust-dark); font: 600 8px/1 var(--font-mono); }
.scenario-list button b { font-size: 11px; line-height: 1.55; }
.response-guide { display: grid; align-content: center; min-height: 330px; padding: 28px; background: var(--paper-light); }
.guide-label { color: var(--green); font: 600 9px/1 var(--font-mono); }
.response-guide h3 { margin: 18px 0 10px; font-size: 19px; line-height: 1.45; }
.response-guide > p { min-height: 78px; margin: 0; color: var(--ink-soft); font-size: 12px; }
.balance-visual { display: grid; gap: 10px; margin-top: 23px; padding-top: 18px; border-top: 1px dashed var(--line-dark); }
.balance-visual div { display: grid; grid-template-columns: 120px 1fr; gap: 10px; align-items: center; }
.balance-visual span { color: var(--ink-soft); font-size: 9px; }
.balance-visual i { height: 7px; border: 1px solid var(--line-dark); background: var(--paper-deep); }
.balance-visual b { display: block; height: 100%; background: var(--green); }
.definition-callout { display: grid; grid-template-columns: 190px 1fr; gap: 18px; margin-top: 13px; padding: 15px; color: var(--white); background: var(--terminal); }
.definition-callout strong { color: #e8d8a8; font: 600 10px/1.5 var(--font-mono); }
.definition-callout span { color: #b7bcae; font-size: 10px; }

.goal-preview { position: relative; min-height: 150px; padding: 25px 28px 25px 110px; overflow: hidden; color: var(--white); background: var(--green); }
.goal-preview::before { position: absolute; top: -28px; left: 15px; color: rgba(255,255,255,.12); content: "“"; font: 160px/1 Georgia, serif; }
.goal-preview span { position: relative; color: #c5d8d0; font: 600 9px/1 var(--font-mono); }
.goal-preview p { position: relative; max-width: 650px; margin: 18px 0 0; font-size: 17px; font-weight: 700; line-height: 1.7; word-break: keep-all; }
.visual-worksheet { margin-top: 10px; }
.visual-worksheet .worksheet-row label { display: flex; gap: 9px; align-items: center; }
.visual-worksheet .worksheet-row label b { display: grid; width: 21px; height: 21px; color: var(--white); border-radius: 50%; background: var(--rust); font: 600 8px/1 var(--font-mono); place-items: center; }

.quiz-section .quiz-question { position: relative; padding-left: 74px; }
.quiz-section .quiz-number { position: absolute; top: 18px; left: 20px; display: grid; width: 35px; height: 35px; color: var(--white); border-radius: 50%; background: var(--rust); place-items: center; }
.takeaway-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 1px; margin: 26px 0; border: 1px solid var(--ink); background: var(--ink); }
.takeaway-grid div { min-height: 120px; padding: 20px; background: var(--paper-light); }
.takeaway-grid span, .takeaway-grid b { display: block; }
.takeaway-grid span { color: var(--rust); font: 600 9px/1 var(--font-mono); }
.takeaway-grid b { margin-top: 30px; font-size: 15px; }
.next-lesson { display: grid; grid-template-columns: 120px 1fr; gap: 20px; margin-top: 20px; padding: 22px; border: 1px solid var(--line-dark); }
.next-lesson > span { color: var(--green); font: 600 9px/1.4 var(--font-mono); }
.next-lesson b { font-size: 14px; }
.next-lesson p { margin: 5px 0 0; color: var(--ink-soft); font-size: 11px; }
.lesson-pager { display: flex; flex-wrap: wrap; gap: 8px; justify-content: space-between; margin: 22px 0 0; }
.lesson-page-link { min-width: 150px; padding: 11px 14px; border: 1px solid var(--line-dark); color: var(--green); font: 600 10px/1.4 var(--font-mono); text-decoration: none; }
.lesson-page-link:last-child { margin-left: auto; text-align: right; }
.lesson-page-link:hover, .lesson-page-link:focus-visible { background: var(--green-light); outline: 2px solid transparent; }
.sources-disclosure { margin-top: 20px; border-top: 1px solid var(--line); }
.sources-disclosure summary { padding: 15px 0; color: var(--green); cursor: pointer; font-size: 11px; font-weight: 700; }
.progress-card { padding: 14px; border: 1px solid var(--green); background: var(--green-light); }
.side-progress-number { display: flex; align-items: end; justify-content: space-between; margin-bottom: 9px; }
.side-progress-number strong { font: 600 22px/1 var(--font-mono); }
.side-progress-number span { color: var(--ink-soft); font-size: 9px; }
.fact-card code { display: block; margin-top: 4px; overflow-wrap: anywhere; font-size: 8px; }

/* Shared visual labs for Days 2–14 */
.concept-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 10px; margin: 22px 0; }
.concept-card, .concept-grid > div { position: relative; min-height: 150px; padding: 20px; overflow: hidden; border: 1px solid var(--line-dark); background: var(--paper-light); }
.concept-card::after, .concept-grid > div::after { position: absolute; right: -8px; bottom: -25px; color: var(--rust); content: attr(data-index); font: 600 74px/1 var(--font-mono); opacity: .08; }
.concept-card > span, .concept-card > b, .concept-card > small, .concept-grid > div > span, .concept-grid > div > b, .concept-grid > div > small { position: relative; z-index: 1; display: block; }
.concept-card > span, .concept-grid > div > span { color: var(--rust); font: 600 9px/1 var(--font-mono); }
.concept-card > b, .concept-grid > div > b { margin-top: 26px; font-size: 16px; line-height: 1.45; }
.concept-card > small, .concept-grid > div > small { margin-top: 7px; color: var(--ink-soft); font-size: 10px; line-height: 1.6; }
.concept-grid > div > p { margin: 7px 0 0; color: var(--ink-soft); font-size: 10px; }

.visual-lab { display: grid; grid-template-columns: minmax(230px, .8fr) minmax(0, 1.2fr); margin: 24px 0; overflow: hidden; border: 1px solid var(--ink); background: var(--paper-light); }
.lab-controls { display: grid; align-content: start; gap: 7px; padding: 22px; border-right: 1px solid var(--ink); background: var(--paper-deep); }
.lab-controls > p { margin: 0 0 9px; color: var(--ink-soft); font-size: 10px; }
.choice-buttons { display: grid; gap: 7px; }
.choice-buttons button, .filter-buttons button { padding: 11px 13px; border: 1px solid var(--line-dark); background: var(--paper-light); text-align: left; cursor: pointer; font-size: 11px; }
.choice-buttons button:hover, .choice-buttons button.active, .filter-buttons button:hover, .filter-buttons button.active { color: var(--white); border-color: var(--green); background: var(--green); }
.choice-result { display: grid; align-content: center; min-height: 280px; padding: 30px; }
.choice-result > span { color: var(--rust); font: 600 9px/1 var(--font-mono); }
.choice-result h3 { margin: 14px 0 8px; font-size: 24px; line-height: 1.35; }
.choice-result p { margin: 0; color: var(--ink-soft); font-size: 13px; }
.choice-result strong { display: inline-block; width: fit-content; margin-top: 24px; padding: 9px 12px; color: var(--white); background: var(--rust); font: 600 12px/1 var(--font-mono); }

.metric-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 8px; margin: 20px 0; }
.metric-card { min-height: 118px; padding: 17px; border: 1px solid var(--line-dark); background: var(--paper-light); }
.metric-card span, .metric-card strong, .metric-card small { display: block; }
.metric-card span { color: var(--ink-soft); font: 600 8px/1 var(--font-mono); }
.metric-card strong { margin-top: 20px; color: var(--green); font: 600 25px/1 var(--font-mono); }
.metric-card small { margin-top: 7px; color: var(--ink-faint); font-size: 9px; }

.range-lab { margin: 22px 0; padding: 24px; border: 1px solid var(--ink); background: var(--paper-light); }
.range-heading { display: flex; gap: 20px; align-items: end; justify-content: space-between; }
.range-heading h3 { margin: 0; font-size: 18px; }
.range-heading strong { color: var(--rust); font: 600 26px/1 var(--font-mono); }
.range-lab input[type="range"] { width: 100%; margin: 24px 0 12px; accent-color: var(--green); }
.range-track { height: 10px; overflow: hidden; border: 1px solid var(--line-dark); background: var(--paper-deep); }
.range-track i { display: block; width: var(--range-progress, 0%); height: 100%; background: var(--green); transition: width .2s ease; }
.range-scale { display: flex; justify-content: space-between; margin-top: 8px; color: var(--ink-faint); font: 500 8px/1 var(--font-mono); }

.pipeline-board { display: flex; gap: 8px; align-items: stretch; margin: 22px 0; overflow-x: auto; }
.pipeline-step { position: relative; flex: 1 0 120px; min-height: 110px; padding: 15px; border: 1px solid var(--line-dark); background: var(--paper-light); }
.pipeline-step:not(:last-child)::after { position: absolute; top: 50%; right: -13px; z-index: 2; display: grid; width: 18px; height: 18px; color: var(--white); border-radius: 50%; content: "›"; background: var(--rust); font: 600 12px/1 var(--font-mono); place-items: center; transform: translateY(-50%); }
.pipeline-step span, .pipeline-step b, .pipeline-step small { display: block; }
.pipeline-step span { color: var(--rust); font: 600 8px/1 var(--font-mono); }
.pipeline-step b { margin-top: 19px; font-size: 12px; }
.pipeline-step small { margin-top: 5px; color: var(--ink-soft); font-size: 9px; line-height: 1.45; }

.code-panel { margin: 22px 0; overflow: hidden; border: 1px solid #080a08; background: var(--terminal); }
.code-panel header { display: flex; justify-content: space-between; padding: 10px 14px; color: #aab2a0; border-bottom: 1px solid #3a4038; font: 500 9px/1.3 var(--font-mono); }
.code-panel pre { margin: 0; padding: 20px; overflow: auto; color: var(--terminal-ink); font: 10px/1.75 var(--font-mono); white-space: pre; }
.code-panel mark { padding: 1px 4px; color: #172019; background: #95c1a8; }

.comparison-table { width: 100%; margin: 22px 0; border-spacing: 0; border-collapse: collapse; background: var(--paper-light); font-size: 11px; }
.comparison-table th, .comparison-table td { padding: 12px; border: 1px solid var(--line-dark); text-align: left; vertical-align: top; }
.comparison-table th { color: var(--white); background: var(--green); font: 600 9px/1.4 var(--font-mono); }
.comparison-table tbody th { color: var(--ink); background: var(--paper-deep); }
.comparison-table td strong, .comparison-table td small { display: block; }
.comparison-table td small { margin-top: 4px; color: var(--ink-soft); }

.filter-buttons { display: flex; flex-wrap: wrap; gap: 6px; margin-bottom: 13px; }
.filter-buttons button { padding: 8px 11px; }
.filter-count { margin-left: auto; align-self: center; color: var(--ink-soft); font: 500 9px/1 var(--font-mono); }
.filter-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 8px; }
.filter-card, .filter-grid > [data-filter-item] { min-height: 120px; padding: 17px; border: 1px solid var(--line-dark); background: var(--paper-light); }
.filter-card[hidden], .filter-grid > [data-filter-item][hidden] { display: none; }
.filter-card span, .filter-card b, .filter-card small, .filter-grid > [data-filter-item] span, .filter-grid > [data-filter-item] b, .filter-grid > [data-filter-item] small { display: block; }
.filter-card span, .filter-grid > [data-filter-item] span { color: var(--rust); font: 600 8px/1 var(--font-mono); }
.filter-card b, .filter-grid > [data-filter-item] b { font-size: 12px; }
.filter-card small, .filter-grid > [data-filter-item] small { margin-top: 5px; color: var(--ink-soft); font-size: 9px; line-height: 1.55; }
.filter-grid > [data-filter-item] p { margin: 8px 0 0; color: var(--ink-soft); font-size: 10px; }

.output-preview { margin: 0; padding: 20px; min-height: 110px; overflow: auto; color: var(--terminal-ink); background: var(--terminal); font: 10px/1.75 var(--font-mono); white-space: pre-wrap; }
.decision-callout { display: grid; grid-template-columns: 110px 1fr; gap: 18px; margin: 20px 0; padding: 18px; border-left: 5px solid var(--rust); background: var(--paper-deep); }
.decision-callout > strong { color: var(--rust-dark); font: 600 10px/1.5 var(--font-mono); }
.decision-callout > p { margin: 0; color: var(--ink-soft); font-size: 11px; }

.focus-mode .course-rail, .focus-mode .notes-rail { display: none; }
.focus-mode .lesson-shell { grid-template-columns: minmax(0, 900px); }
.focus-mode .lesson-main { padding-right: 50px; padding-left: 50px; }

@keyframes instrument-on {
  from { opacity: 1; transform: translateY(8px); }
  to { opacity: 1; transform: translateY(0); }
}
.home-hero > *, .lesson-hero > * { animation: instrument-on .55s ease both; }
.home-hero > *:nth-child(2), .lesson-hero > *:nth-child(2) { animation-delay: .12s; }
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { scroll-behavior: auto !important; animation-duration: .01ms !important; animation-iteration-count: 1 !important; transition-duration: .01ms !important; }
}

@media (max-width: 1120px) {
  .lesson-shell { grid-template-columns: 240px minmax(0, 830px); }
  .notes-rail { display: none; }
  .lesson-header { grid-template-columns: 240px 1fr auto; }
  .phase-lessons { grid-template-columns: repeat(2, 1fr); }
  .method-grid { grid-template-columns: repeat(2, 1fr); }
  .lesson-preview { grid-template-columns: 100px 1fr; }
  .lesson-preview .button { grid-column: 2; justify-self: start; }
}

@media (max-width: 800px) {
  .site-header { min-height: 68px; padding: 10px 18px; }
  .brand small { display: none; }
  .header-gauge { grid-template-columns: auto auto; }
  .header-gauge .gauge-track { display: none; }
  main { width: min(100% - 30px, var(--max)); }
  .home-hero { grid-template-columns: 1fr; gap: 30px; min-height: auto; padding: 44px 0 38px; }
  .hero-copy h1 { font-size: clamp(36px, 10.4vw, 56px); }
  .hero-lede { margin-top: 22px; font-size: 15px; }
  .hero-actions { margin-top: 26px; }
  .instrument-panel { max-width: 500px; animation: none; }
  .course-principle { grid-template-columns: 45px 1fr; }
  .course-principle > p { grid-column: 2; }
  .roadmap-section, .method-section { padding: 65px 0; }
  .section-heading { display: block; }
  .section-heading > p { margin-top: 16px; }
  .phase-header { grid-template-columns: 42px 1fr; }
  .phase-header p { grid-column: 2; }
  .phase-lessons { margin-left: 60px; }
  .lesson-preview { grid-template-columns: 1fr; padding: 30px; }
  .preview-number { font-size: 60px; }
  .lesson-preview .button { grid-column: 1; }

  .lesson-header { grid-template-columns: 1fr auto; min-height: 64px; }
  .lesson-header .brand { padding-left: 15px; }
  .lesson-header-center { display: none; }
  .mobile-course-toggle { display: inline-grid; }
  .focus-toggle { display: none; }
  .lesson-shell { display: block; }
  .course-rail { position: fixed; top: 64px; bottom: 0; left: 0; z-index: 55; width: min(84vw, 330px); height: auto; background: var(--paper); box-shadow: 14px 0 34px rgba(54,45,31,.14); transform: translateX(-105%); transition: transform .22s ease; }
  .course-open .course-rail { transform: translateX(0); }
  .lesson-main { padding: 42px 4px 90px; }
  .lesson-hero h1 { font-size: clamp(39px, 11vw, 58px); }
  .completion-spec { grid-template-columns: 1fr; }
  .worksheet-row { grid-template-columns: 1fr; gap: 5px; }
  .completion-panel { grid-template-columns: 1fr; }

  .lesson-hero-visual::after { right: -55px; width: 145px; height: 145px; opacity: .3; }
  .visual-summary { grid-template-columns: repeat(2, 1fr); }
  .visual-summary li { border-bottom: 1px solid var(--ink); }
  .visual-summary li:nth-child(2n) { border-right: 0; }
  .visual-summary li:last-child { grid-column: 1 / -1; border-bottom: 0; }
  .visual-summary li:not(:last-child)::after { display: none; }
  .station-heading { grid-template-columns: 1fr; gap: 12px; align-items: start; }
  .station-heading > p { max-width: 620px; }
  .section-brief { grid-template-columns: 1fr; margin-top: -10px; }
  .section-brief li { display: grid; grid-template-columns: 120px 1fr; gap: 14px; padding: 13px 15px; border-right: 0; border-bottom: 1px solid var(--line); }
  .section-brief li:last-child { border-bottom: 0; }
  .section-brief b { margin: 2px 0 0; }
  .model-comparison { grid-template-columns: 1fr; gap: 16px; }
  .compare-mark { position: static; margin: -7px auto; transform: none; }
  .output-bubble { min-height: 128px; }
  .two-axis-explainer { grid-template-columns: 1fr; }
  .axis-plus { min-height: 28px; }
  .method-lab { grid-template-columns: 1fr; }
  .method-controls { border-right: 0; border-bottom: 1px solid var(--ink); }
  .weight-grid { max-height: 260px; }
  .inline-checks { grid-template-columns: 1fr; }
  .template-demo { grid-template-columns: 1fr; }
  .transform-button { grid-template-columns: auto auto; gap: 12px; min-height: 52px; }
  .transform-button i { transform: rotate(90deg); }
  .term-deck { grid-template-columns: repeat(2, 1fr); }
  .safety-lab { grid-template-columns: 1fr; }
  .scenario-list { border-right: 0; border-bottom: 1px solid var(--ink); }
  .response-guide { min-height: 280px; }
  .definition-callout { grid-template-columns: 1fr; gap: 7px; }
  .goal-preview { padding-left: 78px; }
  .takeaway-grid { grid-template-columns: 1fr; }
  .next-lesson { grid-template-columns: 90px 1fr; }
  .concept-grid { grid-template-columns: 1fr; }
  .concept-card { min-height: 120px; }
  .visual-lab { grid-template-columns: 1fr; }
  .lab-controls { border-right: 0; border-bottom: 1px solid var(--ink); }
  .choice-result { min-height: 230px; }
  .metric-grid { grid-template-columns: repeat(2, 1fr); }
  .filter-grid { grid-template-columns: 1fr; }
  .comparison-table { display: block; overflow-x: auto; white-space: nowrap; }
}

@media (max-width: 540px) {
  .brand-mark { width: 30px; height: 30px; }
  .brand strong { font-size: 11px; }
  .header-gauge { font-size: 8px; }
  .hero-actions { align-items: stretch; flex-direction: column; }
  .button { width: 100%; }
  .text-link { align-self: center; }
  .course-principle { gap: 18px; }
  .phase-header { grid-template-columns: 35px 1fr; }
  .phase-node { width: 35px; height: 35px; }
  .phase::before { left: 17px; }
  .phase-lessons { grid-template-columns: 1fr; margin-left: 52px; }
  .lesson-card { min-height: 145px; }
  .method-grid { grid-template-columns: 1fr; }
  .method-grid li { min-height: 180px; }
  .method-grid h3 { margin-top: 34px; }
  .site-footer { align-items: flex-start; flex-direction: column; gap: 9px; }
  .metric-grid { grid-template-columns: 1fr; }
  .decision-callout { grid-template-columns: 1fr; gap: 8px; }
  .range-heading { align-items: start; flex-direction: column; }
  .lesson-header-actions .icon-button { min-width: 34px; height: 34px; }
  .lesson-header { min-height: 60px; }
  .course-rail { top: 60px; }
  .lesson-main { padding-top: 32px; }
  .lesson-hero-meta { gap: 5px; }
  .quiz-scorecard { align-items: flex-start; flex-direction: column; }
  .check-row { grid-template-columns: auto 1fr; padding: 13px; }
  .done-stamp { grid-column: 2; justify-self: start; margin-top: 3px; }
  .instrument-panel { padding: 25px 20px 22px; }

  .lesson-hero-visual::after { display: none; }
  .lesson-hero-visual h1 { font-size: clamp(36px, 10vw, 48px); }
  .visual-summary { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); overflow: visible; }
  .visual-summary li { min-height: 136px; border-right: 1px solid var(--ink); border-bottom: 1px solid var(--ink); }
  .visual-summary li:nth-child(2n) { border-right: 0; }
  .visual-summary li:last-child { grid-column: 1 / -1; border-right: 0; border-bottom: 0; }
  .learning-station { padding: 54px 0; }
  .station-heading h2 { font-size: 30px; }
  .section-brief { margin-bottom: 22px; }
  .section-brief li { grid-template-columns: 92px 1fr; gap: 10px; padding: 12px; }
  .prompt-chip { flex: 1 1 100%; }
  .selected-prompt { align-items: flex-start; flex-direction: column; gap: 7px; }
  .model-output header code { white-space: normal; }
  .model-id-note { align-items: start; }
  .method-controls, .weight-visual { padding: 18px; }
  .method-copy { min-height: 108px; }
  .method-metrics div { grid-template-columns: 110px 1fr; }
  .template-panel pre { padding: 16px; font-size: 10px; }
  .template-rules { grid-template-columns: 1fr; }
  .template-rules div { border-right: 0; border-bottom: 1px solid var(--line-dark); }
  .template-rules div:last-child { border-bottom: 0; }
  .term-card-v2 { height: 138px; }
  .term-front, .term-back { padding: 12px; }
  .response-guide { min-height: 260px; padding: 22px; }
  .balance-visual div { grid-template-columns: 105px 1fr; }
  .goal-preview { min-height: 170px; padding: 24px 20px; }
  .goal-preview::before { display: none; }
  .goal-preview p { font-size: 15px; }
  .worksheet-body { padding: 16px; }
  .quiz-section .quiz-question { padding: 64px 16px 18px; }
  .quiz-section .quiz-number { top: 16px; left: 16px; }
  .next-lesson { grid-template-columns: 1fr; gap: 8px; }
}