/* ============================================================
   ResNet 인터랙티브 가이드 — 스타일
   팔레트: 검증된 데이터비주얼라이제이션 기본 팔레트 (light/dark)
   ============================================================ */

:root {
  color-scheme: light;
  --page:           #f9f9f7;
  --surface-1:      #fcfcfb;
  --text-primary:   #0b0b0b;
  --text-secondary: #52514e;
  --text-muted:     #898781;
  --grid:           #e1e0d9;
  --baseline:       #c3c2b7;
  --border:         rgba(11,11,11,0.10);
  --series-1:       #2a78d6;   /* residual (blue) */
  --series-2:       #eb6834;   /* plain (orange) */
  --seq-250:        #86b6ef;
  --seq-350:        #5598e7;
  --seq-450:        #2a78d6;
  --seq-550:        #1c5cab;
  --accent-soft:    rgba(42,120,214,0.10);
  --warn-soft:      rgba(235,104,52,0.12);
  --code-bg:        #f4f3ef;
  --shadow:         0 1px 3px rgba(11,11,11,0.06), 0 4px 16px rgba(11,11,11,0.05);
}
@media (prefers-color-scheme: dark) {
  :root:where(:not([data-theme="light"])) {
    color-scheme: dark;
    --page:           #0d0d0d;
    --surface-1:      #1a1a19;
    --text-primary:   #ffffff;
    --text-secondary: #c3c2b7;
    --text-muted:     #898781;
    --grid:           #2c2c2a;
    --baseline:       #383835;
    --border:         rgba(255,255,255,0.10);
    --series-1:       #3987e5;
    --series-2:       #d95926;
    --seq-250:        #86b6ef;
    --seq-350:        #5598e7;
    --seq-450:        #3987e5;
    --seq-550:        #1c5cab;
    --accent-soft:    rgba(57,135,229,0.16);
    --warn-soft:      rgba(217,89,38,0.18);
    --code-bg:        #141413;
    --shadow:         0 1px 3px rgba(0,0,0,0.4), 0 4px 16px rgba(0,0,0,0.3);
  }
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 64px; }
body {
  margin: 0;
  background: var(--page);
  color: var(--text-primary);
  font-family: system-ui, -apple-system, "Segoe UI", "Apple SD Gothic Neo", "Noto Sans KR", sans-serif;
  line-height: 1.75;
  font-size: 16.5px;
  -webkit-font-smoothing: antialiased;
}

/* ---------- 상단 내비게이션 ---------- */
.topnav {
  position: sticky; top: 0; z-index: 50;
  background: color-mix(in srgb, var(--page) 88%, transparent);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
}
.topnav-inner {
  max-width: 920px; margin: 0 auto; padding: 10px 20px;
  display: flex; align-items: center; gap: 18px;
}
.brand { font-weight: 800; color: var(--text-primary); text-decoration: none; letter-spacing: -0.01em; }
.brand-accent { color: var(--series-1); }
.navlinks { display: flex; gap: 2px; flex-wrap: wrap; margin-left: auto; }
.navlinks a {
  color: var(--text-secondary); text-decoration: none; font-size: 13.5px;
  padding: 4px 9px; border-radius: 7px;
}
.navlinks a:hover { background: var(--accent-soft); color: var(--text-primary); }

/* ---------- 히어로 ---------- */
.hero { max-width: 780px; margin: 0 auto; padding: 72px 20px 30px; text-align: center; }
.hero-kicker {
  font-size: 13px; font-weight: 700; letter-spacing: 0.12em; text-transform: uppercase;
  color: var(--series-1); margin: 0 0 10px;
}
.hero h1 { font-size: clamp(30px, 5.5vw, 46px); line-height: 1.2; margin: 0 0 14px; letter-spacing: -0.02em; }
.hero-lede { font-size: 19px; color: var(--text-secondary); margin: 0 auto 26px; max-width: 560px; }
.hero-formula {
  display: inline-flex; align-items: baseline; gap: 14px;
  font-size: clamp(34px, 7vw, 54px); font-weight: 700; font-style: italic;
  padding: 18px 38px; border-radius: 18px;
  background: var(--surface-1); border: 1px solid var(--border); box-shadow: var(--shadow);
  margin-bottom: 26px;
}
.hf-f { color: var(--series-2); }
.hf-x { color: var(--series-1); }
.hf-plus, .hf-eq { color: var(--text-muted); font-style: normal; font-weight: 400; }
.hero-sub { font-size: 15.5px; color: var(--text-secondary); max-width: 640px; margin: 0 auto; text-align: left; }

/* ---------- 본문 레이아웃 ---------- */
main { max-width: 780px; margin: 0 auto; padding: 0 20px 40px; }
section { padding: 44px 0 10px; border-bottom: 1px solid var(--border); }
section:last-of-type { border-bottom: none; }
h2 { font-size: 27px; line-height: 1.3; letter-spacing: -0.015em; margin: 0 0 18px; display: flex; align-items: center; gap: 12px; }
.secno {
  flex: none; width: 34px; height: 34px; border-radius: 10px;
  background: var(--series-1); color: #fff; font-size: 17px;
  display: inline-flex; align-items: center; justify-content: center;
}
h3 { font-size: 20px; margin: 34px 0 12px; letter-spacing: -0.01em; }
p { margin: 0 0 16px; }
a { color: var(--series-1); }
em { font-style: italic; }

/* ---------- 콜아웃 ---------- */
.callout {
  background: var(--accent-soft); border-left: 3px solid var(--series-1);
  border-radius: 0 12px 12px 0; padding: 14px 18px; margin: 0 0 18px;
}
.callout.analogy { background: var(--warn-soft); border-left-color: var(--series-2); }
.callout-title { font-weight: 700; margin-bottom: 6px; }
.callout p:last-child { margin-bottom: 0; }
.callout ul { margin: 6px 0 0; padding-left: 20px; }
.callout li { margin-bottom: 5px; }

/* ---------- 수식 블록 ---------- */
.formula-block {
  background: var(--surface-1); border: 1px solid var(--border); border-radius: 14px;
  box-shadow: var(--shadow); padding: 18px 22px; margin: 0 0 18px;
  font-size: 18px; overflow-x: auto;
}
.fline { margin: 6px 0; white-space: nowrap; }
.fline em, .fpart { font-style: italic; }
.fsum { font-size: 24px; vertical-align: -2px; }
.fnote { font-size: 13px; color: var(--text-muted); font-style: normal; margin-left: 12px; white-space: normal; }
.hl-one {
  color: var(--series-1); font-size: 1.25em; font-style: normal;
  padding: 0 4px; border-radius: 6px; background: var(--accent-soft);
}

/* ---------- 시각화 카드 ---------- */
.viz-card, .code-card {
  background: var(--surface-1); border: 1px solid var(--border); border-radius: 16px;
  box-shadow: var(--shadow); padding: 18px 20px 16px; margin: 0 0 22px;
}
figure { margin: 0 0 22px; }
figcaption { margin-bottom: 12px; font-size: 15px; }
figcaption strong { display: block; font-size: 16px; }
.cap-note { color: var(--text-muted); font-size: 13px; }
.viz-note { font-size: 14px; color: var(--text-secondary); margin: 12px 0 0; }
.chart { width: 100%; }
.chart svg { display: block; width: 100%; height: auto; }

/* ---------- 컨트롤 ---------- */
.controls {
  display: flex; flex-wrap: wrap; align-items: center; gap: 10px 14px;
  margin-bottom: 14px; font-size: 14px;
}
.ctrl { display: flex; flex-direction: column; gap: 2px; color: var(--text-secondary); min-width: 150px; }
.ctrl output { font-weight: 700; color: var(--text-primary); display: inline; }
.ctrl-label { color: var(--text-secondary); font-weight: 600; }
.ctrl-sep { width: 1px; height: 22px; background: var(--border); }
input[type="range"] { accent-color: var(--series-1); width: 160px; }
.btn {
  font: inherit; font-size: 13.5px; font-weight: 600;
  color: var(--text-primary); background: var(--surface-1);
  border: 1px solid var(--baseline); border-radius: 9px;
  padding: 6px 13px; cursor: pointer;
}
.btn:hover { border-color: var(--series-1); }
.btn.seg.active { background: var(--series-1); border-color: var(--series-1); color: #fff; }
.btn.primary { background: var(--series-1); border-color: var(--series-1); color: #fff; }
.btn.primary:disabled { opacity: 0.55; cursor: default; }

/* ---------- 테이블 ---------- */
.table-wrap { overflow-x: auto; margin: 0 0 18px; }
table {
  border-collapse: collapse; width: 100%; font-size: 14.5px;
  background: var(--surface-1); border: 1px solid var(--border); border-radius: 12px;
  overflow: hidden; box-shadow: var(--shadow);
}
th, td { text-align: left; padding: 9px 14px; border-bottom: 1px solid var(--grid); }
th { font-size: 13px; color: var(--text-muted); font-weight: 600; }
tbody tr:last-child td { border-bottom: none; }
td { font-variant-numeric: tabular-nums; }
.row-best td { background: var(--accent-soft); }
.worse { color: var(--series-2); font-size: 12px; font-weight: 700; }

/* ---------- 블록 애니메이션 (2절) ---------- */
.block-anim { display: flex; justify-content: center; }
.block-anim svg { max-width: 460px; width: 100%; height: auto; }
.ba-box { fill: var(--page); stroke: var(--baseline); stroke-width: 1.2; rx: 8; }
.ba-box-label { fill: var(--text-primary); font-size: 13px; font-weight: 600; }
.ba-sub { fill: var(--text-muted); font-size: 11px; }
.ba-path { stroke: var(--baseline); stroke-width: 1.6; fill: none; }
.ba-skip { stroke: var(--series-1); stroke-width: 2; fill: none; }
.ba-plus { fill: var(--surface-1); stroke: var(--text-secondary); stroke-width: 1.5; }
.ba-formula { font-size: 15px; font-style: italic; fill: var(--text-primary); }

/* ---------- 훈련 데모 (4절) ---------- */
.train-panels { display: flex; gap: 16px; flex-wrap: wrap; margin-top: 14px; justify-content: center; }
.train-panel { text-align: center; }
.tp-head { font-size: 14px; font-weight: 600; margin-bottom: 6px; display: flex; align-items: center; gap: 7px; justify-content: center; }
.tp-acc { color: var(--text-secondary); font-weight: 400; font-variant-numeric: tabular-nums; }
.dot { width: 10px; height: 10px; border-radius: 50%; display: inline-block; }
.dot-res { background: var(--series-1); }
.dot-plain { background: var(--series-2); }
.train-panel canvas {
  border: 1px solid var(--border); border-radius: 12px; background: var(--page);
  width: 240px; height: 240px; display: block;
}

/* ---------- 아키텍처 탐색기 (5절) ---------- */
.arch-view { overflow-x: auto; padding: 6px 0 10px; }
.arch-flow { display: flex; align-items: center; gap: 4px; min-width: max-content; padding: 4px 2px; }
.arch-stem {
  flex: none; border-radius: 8px; padding: 7px 9px; font-size: 11.5px; font-weight: 600;
  background: var(--page); border: 1px solid var(--baseline); color: var(--text-primary);
  text-align: center; line-height: 1.35;
}
.arch-stem small { display: block; color: var(--text-muted); font-weight: 400; font-size: 10.5px; }
.arch-stage { flex: none; display: flex; flex-direction: column; gap: 4px; }
.arch-stage-label { font-size: 11px; color: var(--text-muted); text-align: center; }
.arch-blocks { display: flex; gap: 2px; }
.arch-block {
  width: 14px; height: 44px; border-radius: 4px; cursor: default;
  border: 1px solid transparent;
}
.arch-block.ds { outline: 2px dashed var(--text-muted); outline-offset: -2px; }
.arch-block:hover { border-color: var(--text-primary); }
.arch-arrow { flex: none; color: var(--text-muted); font-size: 13px; padding: 0 2px; }
.arch-stats { display: flex; flex-wrap: wrap; gap: 10px 26px; margin-top: 12px; font-size: 14px; color: var(--text-secondary); }
.arch-stats b { color: var(--text-primary); font-variant-numeric: tabular-nums; }

/* ---------- 병목 비교 (5절) ---------- */
.bottleneck-compare { display: flex; gap: 16px; flex-wrap: wrap; justify-content: center; }
.bnc-col {
  flex: 1 1 240px; max-width: 300px; background: var(--page);
  border: 1px solid var(--border); border-radius: 12px; padding: 14px;
}
.bnc-title { font-weight: 700; font-size: 14.5px; margin-bottom: 3px; }
.bnc-sub { font-size: 12.5px; color: var(--text-muted); margin-bottom: 10px; }
.bnc-layer {
  border-radius: 7px; padding: 6px 10px; margin-bottom: 6px; font-size: 13px;
  background: var(--surface-1); border: 1px solid var(--baseline);
  display: flex; justify-content: space-between; gap: 8px; cursor: default;
  font-variant-numeric: tabular-nums;
}
.bnc-layer:hover { border-color: var(--series-1); }
.bnc-layer .k { color: var(--text-secondary); }
.bnc-total { font-size: 14px; font-weight: 700; margin-top: 10px; display: flex; justify-content: space-between; }
.bnc-total .k { color: var(--text-secondary); font-weight: 600; }

/* ---------- pre-activation 비교 (6절) ---------- */
.preact-compare { display: flex; gap: 16px; flex-wrap: wrap; margin: 0 0 18px; }
.preact-col {
  flex: 1 1 250px; background: var(--surface-1); border: 1px solid var(--border);
  border-radius: 14px; padding: 14px 16px; box-shadow: var(--shadow);
}
.pc-title { font-weight: 700; font-size: 14.5px; margin-bottom: 10px; }
.pc-stack { display: flex; flex-direction: column; gap: 5px; }
.pc-op {
  font-size: 13px; padding: 5px 11px; border-radius: 7px;
  background: var(--page); border: 1px solid var(--baseline);
}
.pc-op.conv { border-left: 3px solid var(--series-1); font-weight: 600; }
.pc-op.add { font-weight: 600; }
.pc-op.warn { border-color: var(--series-2); color: var(--series-2); }
.pc-op.good { border-color: var(--series-1); color: var(--series-1); }

/* ---------- 경로 펼쳐보기 (6절) ---------- */
.up-legend { display: flex; gap: 18px; flex-wrap: wrap; font-size: 13px; color: var(--text-secondary); margin: 0 0 12px; }
.up-legend span { display: inline-flex; align-items: center; gap: 7px; }
.up-chip, .up-cell {
  display: inline-block; text-align: center; padding: 2px 8px; border-radius: 7px;
  border: 1px solid var(--baseline); background: var(--page); color: var(--text-muted); font-size: 12.5px;
}
.up-chip.on, .up-cell.on { background: var(--warn-soft); border-color: var(--series-2); color: var(--series-2); font-weight: 700; }
.up-chip.off, .up-cell.off { border-style: dashed; }
.unravel-head { font-size: 14px; color: var(--text-secondary); margin: 0 0 12px; }
.unravel-head b { color: var(--text-primary); }
.unravel { display: flex; flex-direction: column; gap: 14px; overflow-x: auto; }
.up-group-title { font-size: 12.5px; color: var(--text-muted); margin-bottom: 6px; }
.up-rows { display: flex; flex-direction: column; gap: 5px; }
.up-path { display: flex; align-items: center; gap: 6px; width: max-content; }
.up-path .up-cell { min-width: 34px; }
.up-node { font-style: italic; font-weight: 700; color: var(--text-secondary); font-size: 13px; }

/* ---------- 코드 ---------- */
.code-card { padding: 14px 0 4px; overflow: hidden; }
.code-card figcaption { padding: 0 20px; }
pre {
  margin: 0; padding: 14px 20px 18px; overflow-x: auto;
  background: var(--code-bg); font-size: 13.2px; line-height: 1.6;
}
code { font-family: ui-monospace, "SF Mono", Menlo, Consolas, monospace; }
p code, li code { background: var(--code-bg); padding: 1px 6px; border-radius: 6px; font-size: 0.88em; }
.tok-kw { color: var(--series-1); font-weight: 600; }
.tok-str { color: #1baf7a; }
.tok-com { color: var(--text-muted); font-style: italic; }
.tok-num { color: var(--series-2); }
.tok-star { background: var(--warn-soft); border-radius: 4px; }

/* ---------- 요약 · 참고문헌 ---------- */
.summary-list { padding-left: 22px; margin: 0 0 18px; }
.summary-list li { margin-bottom: 10px; }
.refs { padding-left: 22px; font-size: 14.5px; color: var(--text-secondary); }
.refs li { margin-bottom: 8px; }

/* ---------- 툴팁 ---------- */
.tooltip {
  position: fixed; z-index: 100; pointer-events: none; opacity: 0;
  background: var(--surface-1); color: var(--text-primary);
  border: 1px solid var(--border); border-radius: 10px; box-shadow: var(--shadow);
  padding: 8px 12px; font-size: 12.5px; line-height: 1.5;
  max-width: 260px; transition: opacity 0.08s;
  font-variant-numeric: tabular-nums;
}
.tooltip.show { opacity: 1; }
.tooltip .tt-title { font-weight: 700; margin-bottom: 2px; }
.tooltip .tt-row { display: flex; align-items: center; gap: 6px; }
.tooltip .tt-swatch { width: 8px; height: 8px; border-radius: 2px; flex: none; }

footer {
  border-top: 1px solid var(--border); padding: 24px 20px 40px;
  text-align: center; font-size: 13.5px; color: var(--text-muted);
}

@media (max-width: 560px) {
  body { font-size: 15.5px; }
  .navlinks { display: none; }
  .hero { padding-top: 48px; }
  .hero-formula { padding: 12px 22px; }
}