/* ============================================================
   고등학교 정보과 웹교과서 — 공통 디자인 시스템
   과목 테마: body[data-subject="info" | "ai" | "ds" | "sw"]
   ============================================================ */

/* ---------- 기본 변수 ---------- */
:root {
  --font-sans: "Pretendard Variable", Pretendard, -apple-system, BlinkMacSystemFont,
    "Segoe UI", "Noto Sans KR", "Malgun Gothic", "Apple SD Gothic Neo", sans-serif;
  --font-mono: "JetBrains Mono", "D2Coding", "Cascadia Code", Consolas, monospace;

  --c-bg: #f6f8fb;
  --c-surface: #ffffff;
  --c-text: #1e293b;
  --c-text-soft: #51607a;
  --c-text-faint: #8b97ad;
  --c-border: #e3e9f2;
  --c-shadow: 0 2px 10px rgba(30, 41, 59, .06), 0 8px 30px rgba(30, 41, 59, .05);
  --c-shadow-lg: 0 6px 18px rgba(30, 41, 59, .1), 0 20px 50px rgba(30, 41, 59, .08);

  /* 기본(포털) 테마 = 남색 계열 */
  --c-primary: #3b5bdb;
  --c-primary-deep: #2f4ab8;
  --c-primary-soft: #e7ecfd;
  --c-accent: #0ea5e9;
  --c-accent-soft: #e0f4fe;

  --ok: #16a34a;  --ok-soft: #e6f7ec;
  --warn: #d97706; --warn-soft: #fdf1e0;
  --bad: #dc2626;  --bad-soft: #fdeaea;

  --radius: 16px;
  --radius-sm: 10px;
  --maxw: 1000px;
}

/* 과목별 테마 색 */
body[data-subject="info"] { --c-primary:#2563eb; --c-primary-deep:#1d4ed8; --c-primary-soft:#dbeafe; --c-accent:#0891b2; --c-accent-soft:#dff5f9; }
body[data-subject="ai"]   { --c-primary:#7c3aed; --c-primary-deep:#6d28d9; --c-primary-soft:#ede9fe; --c-accent:#db2777; --c-accent-soft:#fce7f3; }
body[data-subject="ds"]   { --c-primary:#0d9488; --c-primary-deep:#0f766e; --c-primary-soft:#ccfbf1; --c-accent:#2563eb; --c-accent-soft:#dbeafe; }
body[data-subject="sw"]   { --c-primary:#ea580c; --c-primary-deep:#c2410c; --c-primary-soft:#ffedd5; --c-accent:#0d9488; --c-accent-soft:#ccfbf1; }

/* ---------- 리셋 ---------- */
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: var(--font-sans);
  background: var(--c-bg);
  color: var(--c-text);
  line-height: 1.75;
  font-size: 17px;
  word-break: keep-all;
  overflow-wrap: break-word;
  -webkit-font-smoothing: antialiased;
}
img { max-width: 100%; height: auto; display: block; }
a { color: var(--c-primary); text-decoration: none; }
a:hover { text-decoration: underline; }
h1, h2, h3, h4 { line-height: 1.35; font-weight: 800; }
code, pre { font-family: var(--font-mono); }
pre {
  background: #0f172a; color: #e2e8f0; padding: 18px 22px;
  border-radius: var(--radius-sm); overflow-x: auto; font-size: .88em; line-height: 1.7;
}
code:not(pre code) {
  background: var(--c-primary-soft); color: var(--c-primary-deep);
  padding: 2px 7px; border-radius: 6px; font-size: .88em;
}
::selection { background: var(--c-primary); color: #fff; }

/* ---------- 레이아웃 ---------- */
.wrap { max-width: var(--maxw); margin: 0 auto; padding: 0 24px; }

/* ---------- 상단 헤더 ---------- */
.tb-header {
  position: sticky; top: 0; z-index: 100;
  background: rgba(255, 255, 255, .92);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--c-border);
}
.tb-header .bar {
  max-width: var(--maxw); margin: 0 auto; padding: 12px 24px;
  display: flex; align-items: center; gap: 14px;
}
.tb-header .crumb { font-size: .86rem; color: var(--c-text-soft); display: flex; align-items: center; gap: 7px; flex-wrap: wrap; }
.tb-header .crumb a { color: var(--c-text-soft); font-weight: 600; }
.tb-header .crumb a:hover { color: var(--c-primary); text-decoration: none; }
.tb-header .crumb .sep { color: var(--c-text-faint); }
.tb-header .crumb .here { color: var(--c-primary); font-weight: 800; }
.tb-header .spacer { flex: 1; }
.tb-header .home-btn {
  font-size: .82rem; font-weight: 700; color: var(--c-primary);
  border: 1.5px solid var(--c-primary-soft); background: var(--c-primary-soft);
  padding: 6px 14px; border-radius: 99px; white-space: nowrap; transition: all .2s;
}
.tb-header .home-btn:hover { background: var(--c-primary); color: #fff; text-decoration: none; }

/* 읽기 진행 바 */
#scroll-progress {
  position: fixed; top: 0; left: 0; height: 3.5px; width: 0%;
  background: linear-gradient(90deg, var(--c-primary), var(--c-accent));
  z-index: 200; transition: width .1s linear;
}

/* ---------- 히어로 ---------- */
.hero {
  position: relative; overflow: hidden;
  background:
    radial-gradient(1100px 500px at 85% -10%, color-mix(in srgb, var(--c-accent) 38%, transparent), transparent 60%),
    radial-gradient(900px 480px at -10% 110%, color-mix(in srgb, var(--c-primary) 45%, transparent), transparent 55%),
    linear-gradient(135deg, #0b1730, #14224a 55%, #0e1b3a);
  color: #fff;
  padding: 78px 0 70px;
}
.hero .wrap { position: relative; z-index: 2; }
.hero .eyebrow {
  display: inline-flex; align-items: center; gap: 8px;
  font-size: .85rem; font-weight: 700; letter-spacing: .06em;
  color: #cfe0ff; background: rgba(255, 255, 255, .1);
  border: 1px solid rgba(255, 255, 255, .22);
  padding: 7px 16px; border-radius: 99px; margin-bottom: 20px;
}
.hero h1 { font-size: clamp(1.9rem, 4.5vw, 3rem); margin: 0 0 14px; letter-spacing: -.02em; }
.hero p.lead { font-size: clamp(1rem, 2vw, 1.18rem); color: #c6d3ee; max-width: 640px; margin: 0; }
.hero .hero-canvas { position: absolute; inset: 0; z-index: 1; opacity: .65; }

/* ---------- 배지/칩 ---------- */
.std-badge {
  display: inline-flex; align-items: center; gap: 6px;
  font-size: .8rem; font-weight: 800; font-family: var(--font-mono);
  background: var(--c-primary-soft); color: var(--c-primary-deep);
  border: 1px solid color-mix(in srgb, var(--c-primary) 25%, transparent);
  padding: 4px 12px; border-radius: 8px; letter-spacing: .01em;
}
.hero .std-badge { background: rgba(255,255,255,.14); color: #dbe7ff; border-color: rgba(255,255,255,.25); }
.chips { display: flex; flex-wrap: wrap; gap: 9px; margin-top: 22px; }
.chip {
  font-size: .86rem; font-weight: 700; padding: 7px 16px; border-radius: 99px;
  background: rgba(255, 255, 255, .12); color: #e3ecff; border: 1px solid rgba(255, 255, 255, .2);
}
.body-chip { background: var(--c-primary-soft); color: var(--c-primary-deep); border: none; }

/* ---------- 섹션 ---------- */
main { padding: 56px 0 30px; }
.section { margin: 0 0 72px; }
.sec-head { display: flex; align-items: center; gap: 16px; margin-bottom: 26px; }
.sec-num {
  flex: none; width: 46px; height: 46px; border-radius: 14px;
  background: linear-gradient(135deg, var(--c-primary), var(--c-accent));
  color: #fff; font-weight: 900; font-size: 1.25rem;
  display: flex; align-items: center; justify-content: center;
  box-shadow: 0 6px 16px color-mix(in srgb, var(--c-primary) 35%, transparent);
}
.sec-head h2 { margin: 0; font-size: clamp(1.35rem, 3vw, 1.7rem); }
.sec-head .sub { margin: 2px 0 0; color: var(--c-text-soft); font-size: .92rem; }
h3.block-title { font-size: 1.18rem; margin: 38px 0 14px; display: flex; align-items: center; gap: 10px; }
h3.block-title::before {
  content: ""; width: 5px; height: 1.2em; border-radius: 4px;
  background: linear-gradient(180deg, var(--c-primary), var(--c-accent));
}

/* ---------- 카드 ---------- */
.card {
  background: var(--c-surface); border: 1px solid var(--c-border);
  border-radius: var(--radius); padding: 26px 28px; box-shadow: var(--c-shadow);
}
.card-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(230px, 1fr)); gap: 18px; }
/* 카드가 정확히 4개면 3+1·4열 대신 2×2로 정렬(보기 좋게) */
.card-grid:has(> :last-child:nth-child(4)) { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.mini-card {
  background: var(--c-surface); border: 1px solid var(--c-border);
  border-radius: var(--radius); padding: 22px; box-shadow: var(--c-shadow);
  transition: transform .25s, box-shadow .25s;
}
.mini-card:hover { transform: translateY(-4px); box-shadow: var(--c-shadow-lg); }
.mini-card .icon { font-size: 1.9rem; margin-bottom: 10px; }
.mini-card h4 { margin: 0 0 8px; font-size: 1.02rem; }
.mini-card p { margin: 0; font-size: .9rem; color: var(--c-text-soft); line-height: 1.65; }

/* ---------- 정보 박스 ---------- */
.box { border-radius: var(--radius); padding: 22px 26px; margin: 26px 0; border: 1px solid; }
.box .box-label {
  display: inline-flex; align-items: center; gap: 8px; font-weight: 800; font-size: .92rem;
  margin-bottom: 8px;
}
.box p:last-child, .box ul:last-child { margin-bottom: 0; }
.box-tip   { background: var(--c-accent-soft); border-color: color-mix(in srgb, var(--c-accent) 30%, transparent); }
.box-tip .box-label { color: color-mix(in srgb, var(--c-accent) 80%, black); }
.box-warn  { background: var(--warn-soft); border-color: #f3d9ae; }
.box-warn .box-label { color: #b45309; }
.box-think { background: var(--c-primary-soft); border-color: color-mix(in srgb, var(--c-primary) 28%, transparent); }
.box-think .box-label { color: var(--c-primary-deep); }
.box-story { background: #fdf8ef; border-color: #ecdcbe; }
.box-story .box-label { color: #92660a; }

/* 활동 박스 */
.activity {
  border: 2px dashed color-mix(in srgb, var(--c-primary) 45%, transparent);
  background: color-mix(in srgb, var(--c-primary-soft) 45%, white);
  border-radius: var(--radius); padding: 26px 28px; margin: 30px 0;
}
.activity .act-label {
  display: inline-flex; align-items: center; gap: 8px;
  background: var(--c-primary); color: #fff; font-weight: 800; font-size: .88rem;
  padding: 5px 16px; border-radius: 99px; margin-bottom: 14px;
}
.activity ol, .activity ul { padding-left: 22px; }

/* 더 알아보기 (심화) */
details.more-box {
  border: 1.5px solid var(--c-border); border-radius: var(--radius);
  background: var(--c-surface); margin: 22px 0; overflow: hidden; box-shadow: var(--c-shadow);
}
details.more-box > summary {
  cursor: pointer; list-style: none; padding: 18px 24px;
  font-weight: 800; display: flex; align-items: center; gap: 12px;
  transition: background .2s; user-select: none;
}
details.more-box > summary::-webkit-details-marker { display: none; }
details.more-box > summary:hover { background: var(--c-primary-soft); }
details.more-box > summary .plus-tag {
  flex: none; font-size: .76rem; font-weight: 800; color: #fff;
  background: linear-gradient(135deg, var(--c-primary), var(--c-accent));
  padding: 4px 12px; border-radius: 99px;
}
details.more-box > summary::after {
  content: "▾"; margin-left: auto; color: var(--c-text-faint);
  transition: transform .25s; font-size: 1.1rem;
}
details.more-box[open] > summary::after { transform: rotate(180deg); }
details.more-box .more-body { padding: 6px 26px 24px; border-top: 1px dashed var(--c-border); }

/* ---------- 핵심 용어 ---------- */
.term {
  font-weight: 800; color: var(--c-primary-deep);
  border-bottom: 2px dotted color-mix(in srgb, var(--c-primary) 55%, transparent);
  cursor: help; position: relative;
}
.term-pop {
  position: absolute; z-index: 300; max-width: 320px;
  background: #0f172a; color: #e2e8f0; font-size: .85rem; font-weight: 500;
  line-height: 1.6; padding: 12px 16px; border-radius: 12px;
  box-shadow: var(--c-shadow-lg); pointer-events: none;
}
.term-pop strong { color: #93c5fd; display: block; margin-bottom: 2px; }

/* ---------- 그림/도표 ---------- */
figure.img-figure { margin: 30px 0; }
figure.img-figure img {
  width: 100%; border-radius: var(--radius); box-shadow: var(--c-shadow-lg);
  aspect-ratio: 16/9.5; object-fit: cover;
}
figure.img-figure.tall img { aspect-ratio: auto; }
figure.img-figure figcaption {
  margin-top: 12px; font-size: .86rem; color: var(--c-text-soft); text-align: center;
}
figure.img-figure figcaption .src { color: var(--c-text-faint); font-size: .78rem; display: block; margin-top: 2px; }
.fig-row { display: grid; grid-template-columns: 1fr 1fr; gap: 18px; margin: 30px 0; }
.fig-row figure { margin: 0; }
.fig-row figure img { aspect-ratio: 4/3; }

.diagram { margin: 28px 0; text-align: center; }
.diagram svg { max-width: 100%; height: auto; }
.diagram .cap { margin-top: 10px; font-size: .86rem; color: var(--c-text-soft); }

/* ---------- 표 ---------- */
table.tb {
  width: 100%; border-collapse: separate; border-spacing: 0; margin: 26px 0;
  background: var(--c-surface); border: 1px solid var(--c-border);
  border-radius: var(--radius-sm); overflow: hidden; font-size: .94rem;
  box-shadow: var(--c-shadow);
}
table.tb th {
  background: var(--c-primary); color: #fff; font-weight: 800;
  padding: 12px 16px; text-align: left;
}
table.tb td { padding: 12px 16px; border-top: 1px solid var(--c-border); vertical-align: top; }
table.tb tbody tr:nth-child(even) { background: color-mix(in srgb, var(--c-primary-soft) 30%, white); }
table.tb td.hl { font-weight: 800; color: var(--c-primary-deep); white-space: nowrap; }

/* ---------- 탭 ---------- */
.tabs { margin: 26px 0; }
.tabs .tab-btns { display: flex; gap: 8px; flex-wrap: wrap; margin-bottom: -1px; position: relative; z-index: 2; }
.tabs .tab-btn {
  border: 1px solid var(--c-border); border-bottom: none; background: #eef2f8;
  color: var(--c-text-soft); padding: 10px 20px; font: inherit; font-weight: 700; font-size: .92rem;
  border-radius: 12px 12px 0 0; cursor: pointer; transition: all .2s;
}
.tabs .tab-btn.active { background: var(--c-surface); color: var(--c-primary); border-color: var(--c-border); }
.tabs .tab-panel {
  display: none; background: var(--c-surface); border: 1px solid var(--c-border);
  border-radius: 0 var(--radius) var(--radius) var(--radius); padding: 24px 28px;
  box-shadow: var(--c-shadow);
}
.tabs .tab-panel.active { display: block; animation: fadeUp .35s ease; }

/* ---------- 시뮬레이터 패널 ---------- */
.sim-panel {
  background: linear-gradient(180deg, #0f1d3d, #0b1730);
  border-radius: 20px; padding: 0; margin: 34px 0; overflow: hidden;
  box-shadow: var(--c-shadow-lg); border: 1px solid #233358;
}
.sim-panel .sim-head {
  display: flex; align-items: center; gap: 12px; padding: 16px 24px;
  background: rgba(255, 255, 255, .05); border-bottom: 1px solid #233358;
}
.sim-panel .sim-head .dot { width: 11px; height: 11px; border-radius: 50%; }
.sim-panel .sim-head .dot:nth-child(1) { background: #f87171; }
.sim-panel .sim-head .dot:nth-child(2) { background: #fbbf24; }
.sim-panel .sim-head .dot:nth-child(3) { background: #34d399; }
.sim-panel .sim-head .sim-title { color: #dbe7ff; font-weight: 800; font-size: .95rem; margin-left: 6px; }
.sim-panel .sim-head .sim-tag {
  margin-left: auto; font-size: .72rem; font-weight: 800; color: #0b1730;
  background: linear-gradient(90deg, #67e8f9, #a5b4fc); padding: 4px 12px; border-radius: 99px;
}
.sim-panel .sim-body { padding: 24px; color: #cbd5e1; }
.sim-panel .sim-desc { color: #94a3b8; font-size: .88rem; margin: 0 0 16px; }
.sim-controls { display: flex; flex-wrap: wrap; gap: 10px; align-items: center; margin: 14px 0; }
.sim-controls label { font-size: .85rem; color: #94a3b8; font-weight: 700; }
.sim-controls select, .sim-controls input[type="text"], .sim-controls input[type="number"] {
  background: #16254a; color: #e2e8f0; border: 1px solid #2c3f6e;
  border-radius: 8px; padding: 8px 12px; font: inherit; font-size: .9rem;
}
.sim-controls input[type="range"] { accent-color: var(--c-accent); }
.sim-stage { background: #0a1228; border: 1px solid #1d2c54; border-radius: 14px; overflow: hidden; }
.sim-log {
  background: #060d1f; border: 1px solid #1d2c54; border-radius: 10px;
  font-family: var(--font-mono); font-size: .8rem; color: #7dd3fc;
  padding: 12px 16px; margin-top: 14px; max-height: 150px; overflow-y: auto; line-height: 1.8;
}
.sim-log .t { color: #475569; margin-right: 8px; }

/* ---------- 버튼 ---------- */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  background: linear-gradient(135deg, var(--c-primary), var(--c-primary-deep));
  color: #fff; font: inherit; font-weight: 800; font-size: .95rem;
  border: none; padding: 11px 26px; border-radius: 12px; cursor: pointer;
  box-shadow: 0 5px 14px color-mix(in srgb, var(--c-primary) 38%, transparent);
  transition: transform .15s, box-shadow .15s, filter .15s;
}
.btn:hover { transform: translateY(-2px); filter: brightness(1.06); text-decoration: none; }
.btn:active { transform: translateY(0); }
.btn:disabled { opacity: .45; cursor: not-allowed; transform: none; }
.btn.ghost {
  background: transparent; color: var(--c-primary);
  border: 1.5px solid color-mix(in srgb, var(--c-primary) 45%, transparent); box-shadow: none;
}
.btn.ghost:hover { background: var(--c-primary-soft); }
.btn.small { padding: 7px 16px; font-size: .85rem; border-radius: 9px; }
.btn.dark { background: #16254a; border: 1px solid #2c3f6e; box-shadow: none; color: #dbe7ff; }
.btn.dark:hover { background: #1d2f5c; }

/* ---------- 퀴즈 ---------- */
.quiz {
  background: var(--c-surface); border: 1.5px solid var(--c-border);
  border-radius: var(--radius); padding: 28px 30px; margin: 32px 0; box-shadow: var(--c-shadow);
}
.quiz .quiz-head { display: flex; align-items: center; gap: 12px; margin-bottom: 18px; }
.quiz .quiz-head .q-icon {
  width: 40px; height: 40px; flex: none; border-radius: 12px;
  background: linear-gradient(135deg, var(--c-primary), var(--c-accent)); color: #fff;
  display: flex; align-items: center; justify-content: center; font-size: 1.2rem;
}
.quiz .quiz-head h4 { margin: 0; font-size: 1.05rem; }
.quiz .quiz-head .q-sub { font-size: .82rem; color: var(--c-text-soft); margin: 1px 0 0; }
.q-item { padding: 18px 0; border-top: 1px dashed var(--c-border); }
.q-item:first-of-type { border-top: none; }
.q-item .q-text { font-weight: 700; margin: 0 0 13px; }
.q-item .q-text .qno {
  display: inline-flex; align-items: center; justify-content: center;
  min-width: 26px; height: 26px; border-radius: 8px; margin-right: 9px;
  background: var(--c-primary-soft); color: var(--c-primary-deep); font-size: .85rem; font-weight: 900;
}
.q-choices { display: grid; gap: 9px; }
.q-choice {
  text-align: left; font: inherit; font-size: .94rem; cursor: pointer;
  background: #f4f7fb; border: 1.5px solid var(--c-border); border-radius: 12px;
  padding: 11px 18px; transition: all .18s; color: var(--c-text);
}
.q-choice:hover { border-color: var(--c-primary); background: var(--c-primary-soft); }
.q-choice.sel { border-color: var(--c-primary); background: var(--c-primary-soft); font-weight: 800; box-shadow: 0 0 0 3px color-mix(in srgb, var(--c-primary) 18%, transparent); }
.q-choice.picked-right { background: var(--ok-soft); border-color: var(--ok); font-weight: 800; }
.q-choice.picked-wrong { background: var(--bad-soft); border-color: var(--bad); }
.q-choice.show-right { border-color: var(--ok); background: var(--ok-soft); }
.q-choice:disabled { cursor: default; }
.q-feedback {
  display: none; margin-top: 13px; padding: 13px 18px; border-radius: 12px;
  font-size: .9rem; line-height: 1.65;
}
.q-feedback.on { display: block; animation: fadeUp .3s ease; }
.q-feedback.good { background: var(--ok-soft); color: #14532d; border: 1px solid #b3e6c5; }
.q-feedback.bad { background: var(--bad-soft); color: #7f1d1d; border: 1px solid #f5c5c5; }
.q-feedback .verdict { font-weight: 900; display: block; margin-bottom: 3px; }

/* OX 버튼 */
.q-choices.ox { grid-template-columns: 1fr 1fr; }
.q-choices.ox .q-choice { text-align: center; font-size: 1.3rem; font-weight: 900; padding: 14px; }

/* 분류(클릭 게임) */
.classify { margin: 14px 0; }
.classify .pool { display: flex; flex-wrap: wrap; gap: 10px; margin-bottom: 16px; }
.classify .c-item {
  font: inherit; font-size: .9rem; font-weight: 700; cursor: pointer;
  background: var(--c-surface); border: 1.5px solid var(--c-border);
  padding: 9px 18px; border-radius: 99px; transition: all .2s; box-shadow: var(--c-shadow);
}
.classify .c-item.sel { border-color: var(--c-primary); background: var(--c-primary-soft); transform: scale(1.05); }
.classify .c-item.done { opacity: 0; pointer-events: none; transform: scale(.5); }
.classify .bins { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
.classify .bin {
  min-height: 120px; border: 2px dashed var(--c-border); border-radius: var(--radius);
  padding: 14px 16px; cursor: pointer; transition: all .2s; background: #fbfcfe;
}
.classify .bin:hover { border-color: var(--c-primary); background: var(--c-primary-soft); }
.classify .bin h5 { margin: 0 0 10px; font-size: .95rem; color: var(--c-primary-deep); }
.classify .bin .placed { display: flex; flex-wrap: wrap; gap: 7px; }
.classify .bin .placed span {
  font-size: .82rem; font-weight: 700; padding: 5px 13px; border-radius: 99px;
  animation: popIn .3s ease;
}
.classify .bin .placed span.right { background: var(--ok-soft); color: #14532d; border: 1px solid #b3e6c5; }
.classify .bin .placed span.wrong { background: var(--bad-soft); color: #7f1d1d; border: 1px solid #f5c5c5; text-decoration: line-through; }
.classify .c-result { font-weight: 800; margin-top: 14px; min-height: 1.5em; }

/* 서술형 자기 점검 */
.self-check { margin: 16px 0; }
.self-check textarea {
  width: 100%; min-height: 90px; font: inherit; font-size: .93rem;
  border: 1.5px solid var(--c-border); border-radius: 12px; padding: 13px 16px; resize: vertical;
}
.self-check textarea:focus { outline: 2px solid var(--c-primary); border-color: transparent; }
.self-check .model-answer {
  display: none; margin-top: 12px; background: var(--c-primary-soft);
  border: 1px solid color-mix(in srgb, var(--c-primary) 25%, transparent);
  border-radius: 12px; padding: 15px 19px; font-size: .92rem;
}
.self-check .model-answer.on { display: block; animation: fadeUp .3s ease; }
.self-check .model-answer .ma-label { font-weight: 900; color: var(--c-primary-deep); display: block; margin-bottom: 5px; }

/* ---------- 채점 결과 ---------- */
.score-board {
  display: none; margin-top: 22px; text-align: center;
  background: linear-gradient(135deg, var(--c-primary-soft), var(--c-accent-soft));
  border-radius: var(--radius); padding: 26px;
}
.score-board.on { display: block; animation: popIn .4s ease; }
.score-board .score-num { font-size: 2.6rem; font-weight: 900; color: var(--c-primary-deep); }
.score-board .score-msg { font-weight: 700; color: var(--c-text-soft); }

/* ---------- 타임라인 ---------- */
.timeline { position: relative; margin: 30px 0; padding-left: 34px; }
.timeline::before {
  content: ""; position: absolute; left: 11px; top: 6px; bottom: 6px; width: 3px;
  background: linear-gradient(180deg, var(--c-primary), var(--c-accent)); border-radius: 4px;
}
.timeline .tl-item { position: relative; padding: 0 0 26px; }
.timeline .tl-item:last-child { padding-bottom: 0; }
.timeline .tl-item::before {
  content: ""; position: absolute; left: -30px; top: 7px; width: 13px; height: 13px;
  border-radius: 50%; background: #fff; border: 3.5px solid var(--c-primary);
  box-shadow: 0 0 0 4px color-mix(in srgb, var(--c-primary) 18%, transparent);
}
.timeline .tl-when { font-weight: 900; color: var(--c-primary-deep); font-size: .92rem; }
.timeline .tl-item h4 { margin: 2px 0 4px; font-size: 1.02rem; }
.timeline .tl-item p { margin: 0; font-size: .92rem; color: var(--c-text-soft); }

/* ---------- 단계 스텝퍼 ---------- */
.stepper { display: grid; grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); gap: 12px; margin: 28px 0; }
.step-card {
  position: relative; background: var(--c-surface); border: 1.5px solid var(--c-border);
  border-radius: var(--radius); padding: 20px 18px 18px; text-align: center;
  cursor: pointer; transition: all .25s;
}
.step-card:hover, .step-card.active { border-color: var(--c-primary); box-shadow: var(--c-shadow-lg); transform: translateY(-3px); }
.step-card .step-no {
  width: 34px; height: 34px; margin: 0 auto 10px; border-radius: 50%;
  background: var(--c-primary-soft); color: var(--c-primary-deep);
  font-weight: 900; display: flex; align-items: center; justify-content: center;
}
.step-card.active .step-no { background: var(--c-primary); color: #fff; }
.step-card h5 { margin: 0 0 6px; font-size: .97rem; }
.step-card p { margin: 0; font-size: .82rem; color: var(--c-text-soft); line-height: 1.55; }
.step-detail {
  display: none; background: var(--c-primary-soft); border-radius: var(--radius);
  padding: 20px 26px; margin-top: 14px; font-size: .94rem;
}
.step-detail.on { display: block; animation: fadeUp .3s ease; }

/* ---------- 하단 내비게이션 ---------- */
.nav-foot {
  display: grid; grid-template-columns: 1fr 1fr; gap: 16px;
  margin: 60px 0 30px;
}
.nav-foot a {
  display: flex; flex-direction: column; gap: 4px;
  background: var(--c-surface); border: 1.5px solid var(--c-border);
  border-radius: var(--radius); padding: 18px 24px; transition: all .2s;
  box-shadow: var(--c-shadow);
}
.nav-foot a:hover { border-color: var(--c-primary); transform: translateY(-3px); text-decoration: none; box-shadow: var(--c-shadow-lg); }
.nav-foot a .dir { font-size: .8rem; font-weight: 800; color: var(--c-text-faint); }
.nav-foot a .where { font-weight: 800; color: var(--c-text); }
.nav-foot a.next { text-align: right; align-items: flex-end; }
.nav-foot a.disabled { opacity: .4; pointer-events: none; }

footer.tb-footer {
  border-top: 1px solid var(--c-border); background: var(--c-surface);
  padding: 28px 0; text-align: center; font-size: .84rem; color: var(--c-text-faint);
}

/* ---------- 스크롤 리빌 ---------- */
.reveal { opacity: 0; transform: translateY(26px); transition: opacity .7s ease, transform .7s ease; }
.reveal.in { opacity: 1; transform: none; }
.reveal-d1 { transition-delay: .1s; } .reveal-d2 { transition-delay: .2s; } .reveal-d3 { transition-delay: .3s; }

@keyframes fadeUp { from { opacity: 0; transform: translateY(12px); } to { opacity: 1; transform: none; } }
@keyframes popIn { 0% { opacity: 0; transform: scale(.6); } 70% { transform: scale(1.06); } 100% { opacity: 1; transform: scale(1); } }
@keyframes pulse-glow { 0%,100% { box-shadow: 0 0 0 0 color-mix(in srgb, var(--c-primary) 45%, transparent); } 50% { box-shadow: 0 0 0 12px transparent; } }
@keyframes floaty { 0%,100% { transform: translateY(0); } 50% { transform: translateY(-9px); } }
@keyframes spin { to { transform: rotate(360deg); } }

/* ---------- 목차(단원 로드맵) ---------- */
.roadmap { display: grid; gap: 16px; margin: 28px 0; }
.roadmap a.rm-item {
  display: flex; align-items: center; gap: 18px;
  background: var(--c-surface); border: 1.5px solid var(--c-border);
  border-radius: var(--radius); padding: 20px 24px; transition: all .22s; box-shadow: var(--c-shadow);
}
.roadmap a.rm-item:hover { border-color: var(--c-primary); transform: translateX(6px); text-decoration: none; box-shadow: var(--c-shadow-lg); }
.roadmap .rm-no {
  flex: none; width: 50px; height: 50px; border-radius: 16px;
  background: linear-gradient(135deg, var(--c-primary), var(--c-accent)); color: #fff;
  display: flex; align-items: center; justify-content: center; font-weight: 900; font-size: 1.05rem;
}
.roadmap .rm-body { flex: 1; }
.roadmap .rm-body h4 { margin: 0 0 3px; font-size: 1.05rem; }
.roadmap .rm-body p { margin: 0; font-size: .86rem; color: var(--c-text-soft); }
.roadmap .rm-arrow { color: var(--c-text-faint); font-size: 1.3rem; }

/* ---------- 포털/인덱스 페이지 ---------- */
.subject-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); gap: 22px; margin: 40px 0; }
.subject-card {
  position: relative; overflow: hidden; border-radius: 22px; padding: 30px 28px;
  color: #fff; min-height: 230px; display: flex; flex-direction: column;
  transition: transform .25s, box-shadow .25s; box-shadow: var(--c-shadow-lg);
}
.subject-card:hover { transform: translateY(-6px) scale(1.01); text-decoration: none; }
.subject-card .sc-type { font-size: .8rem; font-weight: 800; opacity: .85; letter-spacing: .05em; }
.subject-card h3 { margin: 6px 0 10px; font-size: 1.5rem; }
.subject-card p { margin: 0; font-size: .9rem; opacity: .92; line-height: 1.6; }
.subject-card .sc-meta { margin-top: auto; padding-top: 18px; display: flex; gap: 8px; flex-wrap: wrap; }
.subject-card .sc-meta span {
  font-size: .78rem; font-weight: 700; background: rgba(255,255,255,.18);
  border: 1px solid rgba(255,255,255,.25); padding: 4px 12px; border-radius: 99px;
}
.subject-card .sc-deco {
  position: absolute; right: -40px; bottom: -40px; width: 170px; height: 170px;
  border-radius: 50%; background: rgba(255,255,255,.12); pointer-events: none;
}
.subject-card .sc-deco::after {
  content: ""; position: absolute; inset: 28px; border-radius: 50%; background: rgba(255,255,255,.12);
}

.unit-list { display: grid; gap: 18px; margin: 36px 0; }
.unit-card {
  display: flex; gap: 20px; align-items: center;
  background: var(--c-surface); border: 1.5px solid var(--c-border);
  border-radius: var(--radius); padding: 24px 28px; box-shadow: var(--c-shadow);
  transition: all .22s;
}
a.unit-card:hover { border-color: var(--c-primary); transform: translateY(-3px); text-decoration: none; box-shadow: var(--c-shadow-lg); }
.unit-card .u-no {
  flex: none; width: 58px; height: 58px; border-radius: 18px; font-size: 1.15rem;
  background: linear-gradient(135deg, var(--c-primary), var(--c-accent)); color: #fff;
  display: flex; align-items: center; justify-content: center; font-weight: 900;
}
.unit-card.locked .u-no { background: #cbd5e1; }
.unit-card .u-body { flex: 1; }
.unit-card .u-body h3 { margin: 0 0 5px; font-size: 1.15rem; }
.unit-card .u-body p { margin: 0; font-size: .87rem; color: var(--c-text-soft); }
.unit-card .u-stds { margin-top: 9px; display: flex; gap: 6px; flex-wrap: wrap; }
.unit-card .u-stds .std-badge { font-size: .7rem; padding: 2px 8px; }
.unit-card .u-state { flex: none; font-size: .82rem; font-weight: 800; padding: 7px 16px; border-radius: 99px; white-space: nowrap; }
.unit-card .u-state.open { background: var(--ok-soft); color: #15803d; animation: pulse-glow 2.5s infinite; }
.unit-card .u-state.lock { background: #eef1f6; color: var(--c-text-faint); }
.unit-card.locked { opacity: .72; }

/* ---------- 비교 카드(VS) ---------- */
.vs-grid { display: grid; grid-template-columns: 1fr auto 1fr; gap: 14px; align-items: stretch; margin: 28px 0; }
.vs-grid .vs-side {
  background: var(--c-surface); border: 1.5px solid var(--c-border);
  border-radius: var(--radius); padding: 22px 24px; box-shadow: var(--c-shadow);
}
.vs-grid .vs-side h4 { margin: 0 0 12px; display: flex; align-items: center; gap: 9px; }
.vs-grid .vs-side ul { margin: 0; padding-left: 20px; font-size: .92rem; }
.vs-grid .vs-side li { margin-bottom: 7px; }
.vs-grid .vs-mid {
  align-self: center; font-weight: 900; font-size: 1.1rem; color: #fff;
  background: linear-gradient(135deg, var(--c-primary), var(--c-accent));
  width: 52px; height: 52px; border-radius: 50%;
  display: flex; align-items: center; justify-content: center;
  box-shadow: 0 6px 16px color-mix(in srgb, var(--c-primary) 35%, transparent);
}

/* ---------- 자가평가 ---------- */
.self-assess { display: grid; gap: 14px; margin: 26px 0; }
.sa-item {
  background: var(--c-surface); border: 1.5px solid var(--c-border);
  border-radius: var(--radius); padding: 20px 24px; box-shadow: var(--c-shadow);
}
.sa-item .sa-q { font-weight: 700; margin: 0 0 12px; }
.sa-item .sa-opts { display: flex; gap: 9px; flex-wrap: wrap; }
.sa-item .sa-opt {
  font: inherit; font-size: .87rem; font-weight: 700; cursor: pointer;
  border: 1.5px solid var(--c-border); background: #f4f7fb; color: var(--c-text-soft);
  padding: 8px 20px; border-radius: 99px; transition: all .18s;
}
.sa-item .sa-opt:hover { border-color: var(--c-primary); }
.sa-item .sa-opt.on { background: var(--c-primary); border-color: var(--c-primary); color: #fff; }

/* ---------- 파이썬 실행기 ---------- */
.pyrun {
  border-radius: var(--radius); overflow: hidden; border: 1px solid #233358;
  margin: 26px 0; box-shadow: var(--c-shadow-lg); background: #0f1d3d;
}
.pyrun .py-cap {
  display: flex; align-items: center; gap: 10px; padding: 12px 18px;
  color: #dbe7ff; font-weight: 800; font-size: .9rem;
  background: rgba(255, 255, 255, .05); border-bottom: 1px solid #233358;
}
.pyrun .py-cap::before { content: "🐍"; }
.pyrun .py-cap .py-tag {
  margin-left: auto; font-size: .7rem; font-weight: 800; color: #0b1730;
  background: linear-gradient(90deg, #4ade80, #67e8f9); padding: 3px 11px; border-radius: 99px;
}
.pyrun textarea.py-code {
  display: block; width: 100%; border: none; background: #0a1228; color: #e2e8f0;
  font-family: var(--font-mono); font-size: .88rem; line-height: 1.75;
  padding: 14px 18px; resize: vertical; min-height: 100px; outline: none; tab-size: 4;
}
.pyrun textarea.py-code:focus { background: #0c1530; }
.pyrun .py-bar { display: flex; gap: 8px; align-items: center; padding: 10px 14px; flex-wrap: wrap; }
.pyrun .py-status { font-size: .78rem; color: #7c93c4; font-weight: 700; }
.pyrun .py-out {
  margin: 0; background: #060d1f; color: #7dd3fc; font-size: .85rem; line-height: 1.7;
  padding: 12px 18px; border-top: 1px dashed #233358; max-height: 280px; overflow: auto;
  white-space: pre-wrap; word-break: break-all; border-radius: 0; font-family: var(--font-mono);
}
.pyrun .py-out .err { color: #fca5a5; }
.pyrun .py-out .sys { color: #475569; }

/* ---------- 인쇄 ---------- */
@media print {
  .tb-header, #scroll-progress, .nav-foot, .btn, footer.tb-footer { display: none !important; }
  body { background: #fff; }
  .sim-panel { display: none; }
}

/* ---------- 반응형 ---------- */
@media (max-width: 760px) {
  body { font-size: 16px; }
  .hero { padding: 54px 0 48px; }
  .fig-row { grid-template-columns: 1fr; }
  .vs-grid { grid-template-columns: 1fr; }
  .vs-grid .vs-mid { justify-self: center; }
  .classify .bins { grid-template-columns: 1fr; }
  .nav-foot { grid-template-columns: 1fr; }
  .card-grid:has(> :last-child:nth-child(4)) { grid-template-columns: 1fr; }
  .card, .quiz { padding: 22px 20px; }
  .sec-head { gap: 12px; }
  .tb-header .crumb { font-size: .78rem; }
}