/**
 * InkField Tech Series — 共用基礎樣式
 * 明亮當代藝廊風格（2026-03-10 redesign）
 */

/* ── Variables ── */
:root {
  --bg: #fafafa;
  --card: #ffffff;
  --accent: #1a1a1a;
  --accent2: #e0e0e0;
  --text: #2a2a2a;
  --muted: #888888;
  --green: #2d6a4f;
  --yellow: #b8860b;
  --blue: #1a5276;
  --purple: #6c3483;
  --orange: #a0522d;
  --pink: #c0392b;
  --red: #c0392b;
  --hero-banner-h: 320px;
}

/* ── Reset ── */
* { margin: 0; padding: 0; box-sizing: border-box; }

/* ── Body ── */
body {
  font-family: "Noto Sans TC", "PingFang TC", "Microsoft JhengHei", -apple-system, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.9;
  overflow-x: hidden;
}

/* ── Hero / Banner ── */
.hero {
  position: relative;
  text-align: center;
  padding: 80px 20px 40px;
  /* 確保導覽列有足夠空間在 banner 下方的白色區域 */
  min-height: 570px;
  background: #fff;
  overflow: hidden;
}
.hero::before {
  content: "";
  position: absolute; top: 0; left: 0; right: 0;
  height: var(--hero-banner-h);
  background: url('assets/banner.png') center/cover no-repeat;
  filter: none;
  opacity: 0.85;
  filter: contrast(1.08) saturate(1.08);
  pointer-events: none;
}
.hero::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  top: var(--hero-banner-h);
  border-bottom: 4px solid rgba(0,0,0,0.85);
  pointer-events: none;
}
.hero-back {
  position: absolute; top: 16px;
  left: 16px;
  display: inline-flex; align-items: center;
  padding: 8px 14px 8px 20px;
  background: transparent;
  text-decoration: none; border-radius: 8px;
  font-size: 0.9em; transition: opacity 0.2s;
}
.hero-back:hover { opacity: 0.6; }
.hero-back-logo {
  height: calc(4.3em * 1.5 * 1.2 * 1.2); vertical-align: middle;
  transition: opacity 0.2s;
  mix-blend-mode: multiply;
}
.hero-lang {
  position: absolute; top: 20px; right: 20px;
  font-size: 0.9em; z-index: 10;
  padding: 6px 12px 8px;
  background: #ffffff;
}
.hero-lang a {
  color: var(--text); text-decoration: none;
  padding: 4px 8px; border-radius: 4px;
}
.hero-lang a:hover { background: rgba(0,0,0,0.06); }
.hero-lang .active { font-weight: bold; }
.hero h1 {
  font-family: "Noto Serif TC", "Source Han Serif TC", Georgia, "Times New Roman", serif;
  font-size: 2.08em; margin-bottom: 10px;
  font-weight: 700; color: var(--accent);
  letter-spacing: 0.02em;
  position: relative;
  /* 僅有 span 的頁（如藝廊）也保留一行主標高度，與其他頁一致 */
  min-height: 1.9em;
  text-shadow: none;
  display: inline-block;
  padding: 8px 22px 10px;
  background: #ffffff;
  /* 寬螢幕並排時，與說明字卡保留至少 50px 間距 */
  margin-right: 50px;
}
.hero h1 span {
  display: block;
  font-weight: 400;
  font-size: 0.55em;
  letter-spacing: 0.15em;
  margin-top: 4px;
  color: var(--accent);
}
.hero p {
  color: var(--accent); font-size: 0.88em;
  max-width: 600px; margin: 0 auto;
  font-style: italic;
  position: relative;
  /* 固定兩行高度，避免一行時版面壓縮、下方按鈕離開白色區 */
  min-height: 4.2em;
  text-shadow: none;
  display: inline-block;
  padding: 6px 18px 10px;
  background: #ffffff;
  margin-top: 10px;
}

/* ── Series Navigation ── */
.series-nav {
  max-width: 800px;
  /* 固定在 banner 底線下方，不受標題長短影響 */
  margin: 0 auto;
  padding: 0 20px;
  position: absolute;
  left: 50%;
  transform: translateX(-50%);
  bottom: 20px;
  text-align: left;
}
:lang(en) .series-nav { bottom: 20px; }
.series-grid {
  display: grid;
  grid-template-columns: repeat(3, auto);
  gap: 0 56px;
  justify-content: start;
}
.series-col { display: block; }
.series-col-label {
  font-family: "Noto Serif TC", "Source Han Serif TC", Georgia, "Times New Roman", serif;
  font-size: 1.35em; color: var(--accent);
  letter-spacing: 0.04em;
  font-weight: 400;
  margin-bottom: 8px;
  display: flex;
  align-items: center;
  gap: 14px;
}
.series-col-label::after {
  content: "";
  flex: 1 1 auto;
  border-bottom: 2px solid rgba(0,0,0,0.55);
  transform: translateY(1px);
}
.series-link {
  display: block; padding: 3px 0;
  background: transparent;
  text-decoration: none; color: var(--muted);
  font-family: "Noto Serif TC", "Source Han Serif TC", Georgia, "Times New Roman", serif;
  font-size: 1.1em;
  letter-spacing: 0.02em;
  transition: color 0.2s;
}
.series-link:hover {
  color: var(--accent);
}
.series-link.active {
  color: var(--accent);
  font-weight: 600;
}

/* ── Table of Contents ── */
.toc {
  max-width: 700px; margin: 48px auto;
  padding: 36px 44px;
  background: var(--card); border-radius: 4px;
  border-left: 3px solid var(--accent);
  box-shadow: 0 1px 4px rgba(0,0,0,0.04);
}
.toc h2 {
  margin-bottom: 16px; font-size: 1.2em;
  font-family: "Noto Serif TC", "Source Han Serif TC", Georgia, serif;
  font-weight: 600; letter-spacing: 0.05em;
  display: flex;
  align-items: center;
  gap: 16px;
}
.toc h2::after {
  content: "";
  flex: 1 1 auto;
  border-bottom: 2px solid rgba(0,0,0,0.55);
  transform: translateY(1px);
}
.toc p {
  font-family: "Noto Serif TC", "Source Han Serif TC", Georgia, serif;
  letter-spacing: 0.08em;
}
.toc p + ol { margin-top: 10px; }
.toc p[style*="Part"] {
  padding-bottom: 10px;
  border-bottom: 1px solid rgba(0,0,0,0.18);
}
.toc ol { padding-left: 24px; }
.toc li { margin: 6px 0; }
.toc a { color: var(--text); text-decoration: none; }
.toc a:hover { text-decoration: underline; }

/* ── Content Area ── */
.content { max-width: 800px; margin: 0 auto; padding: 0 20px 80px; }

/* ── Chapters ── */
.chapter { margin-top: 72px; scroll-margin-top: 30px; }
.chapter-header {
  display: flex;
  align-items: flex-end;
  gap: 16px;
  margin-bottom: 24px;
}
.chapter-num {
  width: 44px; height: 44px;
  background: var(--accent); color: #fff; border-radius: 50%;
  display: flex; align-items: center; justify-content: center;
  font-weight: bold; font-size: 1.15em; flex-shrink: 0;
}
.chapter-header h2 {
  font-family: "Noto Serif TC", "Source Han Serif TC", Georgia, serif;
  font-size: 1.5em; font-weight: 600;
  letter-spacing: 0.02em;
  line-height: 1.25;
  margin: 0;
}
/* 分隔設計：標題右側延伸線段（參考附圖） */
.chapter-header h2::after {
  content: "";
  display: inline-block;
  vertical-align: middle;
  width: clamp(120px, 22vw, 360px);
  margin-left: 18px;
  border-bottom: 1px solid rgba(0,0,0,0.55);
}

/* ── Cards ── */
.card {
  background: var(--card); border-radius: 4px;
  padding: 24px 28px; margin: 20px 0;
  border-left: 3px solid var(--accent2);
  box-shadow: 0 1px 3px rgba(0,0,0,0.04);
}
.card h3 {
  font-family: "Noto Serif TC", "Source Han Serif TC", Georgia, serif;
  font-weight: 600;
}
.card.green  { border-left-color: var(--green); }
.card.yellow { border-left-color: var(--yellow); }
.card.blue   { border-left-color: var(--blue); }
.card.purple { border-left-color: var(--purple); }
.card.orange { border-left-color: var(--orange); }
.card.pink   { border-left-color: var(--pink); }
.card.red    { border-left-color: var(--red); }

/* ── Analogy Box ── */
.analogy {
  background: #f4f9f6;
  border: 1px solid #d5e8dc; border-radius: 4px;
  padding: 20px 24px; margin: 16px 0;
}
.analogy::before {
  content: "生活比喻";
  display: inline-block; background: var(--green); color: #fff;
  font-size: 0.72em; font-weight: 600;
  padding: 2px 10px; border-radius: 3px; margin-bottom: 10px;
}

/* ── Code Block ── */
.code {
  background: #f6f8fa; border-radius: 4px;
  padding: 16px 20px;
  font-family: "SF Mono", "Fira Code", "Consolas", monospace;
  font-size: 0.88em; line-height: 1.6;
  overflow-x: auto; margin: 14px 0;
  color: #24292f;
  border: 1px solid #d0d7de;
}
.code .comment { color: #6a737d; }
.code .keyword { color: #cf222e; }
.code .val { color: #0550ae; }

/* ── Tables ── */
.summary-table { width: 100%; border-collapse: collapse; margin: 16px 0; font-size: 0.92em; }
.summary-table th {
  background: #f6f8fa; padding: 10px 14px;
  text-align: left; font-weight: 600;
  border-bottom: 2px solid var(--accent2);
}
.summary-table td {
  padding: 10px 14px;
  border-bottom: 1px solid #eee;
  vertical-align: top;
}
.summary-table tr:hover td { background: rgba(0,0,0,0.015); }

/* ── Tags ── */
.tag { display: inline-block; padding: 2px 10px; border-radius: 3px; font-size: 0.78em; font-weight: 600; }
.tag.shader { background: var(--purple); color: #fff; }
.tag.concept { background: var(--orange); color: #fff; }

/* ── Image Grids ── */
.img-grid { display: grid; gap: 12px; margin: 20px 0; }
.img-grid.cols-2 { grid-template-columns: repeat(2, 1fr); }
.img-grid.cols-3 { grid-template-columns: repeat(3, 1fr); }
.img-grid.cols-4 { grid-template-columns: repeat(4, 1fr); }
.img-grid figure { margin: 0; text-align: center; }
.img-grid img { width: 100%; border-radius: 4px; display: block; }
.img-grid figcaption { font-size: 0.82em; color: var(--muted); margin-top: 6px; }

/* ── Footer ── */
footer { text-align: center; padding: 40px 20px; color: var(--muted); font-size: 0.9em; }
footer a { color: var(--text); text-decoration: none; }

/* ── Scroll-to-top Button ── */
.scroll-to-top {
  position: fixed; right: 24px; bottom: 32px;
  width: 44px; height: 44px; border: 1px solid var(--accent2); border-radius: 50%;
  background: var(--card); color: var(--accent);
  font-size: 1.3em; line-height: 1; cursor: pointer;
  box-shadow: 0 2px 8px rgba(0,0,0,0.08);
  transition: transform 0.2s, box-shadow 0.2s; z-index: 1000;
}
.scroll-to-top:hover { transform: translateY(-2px); box-shadow: 0 4px 12px rgba(0,0,0,0.12); }

/* ── Responsive ── */
@media (max-width: 600px) {
  :root { --hero-banner-h: 200px; }
  .hero {
    /* 用 padding-top 把所有內容推到 banner 下方，不再重疊 */
    padding: calc(var(--hero-banner-h) + 16px) 16px 24px;
    min-height: auto;
  }
  .hero-back { top: 8px; left: 8px; }
  .hero-back-logo { height: 3.5em; }
  .hero h1 {
    font-size: 1.2em; min-height: auto;
    padding: 6px 14px 8px; margin-right: 0; margin-top: 0;
  }
  .hero p {
    font-size: 0.78em; min-height: auto;
    padding: 4px 12px 8px; margin-top: 6px;
  }
  .hero-lang { top: 10px; right: 10px; font-size: 0.8em; padding: 4px 8px 6px; }
  /* 手機上導覽列回歸正常文件流，不用 absolute */
  .series-nav {
    position: relative;
    left: auto; bottom: auto;
    transform: none;
    margin-top: 20px;
    padding: 0 4px;
  }
  :lang(en) .series-nav { bottom: auto; }
  .series-grid { grid-template-columns: 1fr 1fr; gap: 16px 20px; }
  .series-col-label { font-size: 1.2em; }
  .series-link { font-size: 0.82em; }
  .chapter-header h2 { font-size: 1.2em; }
  .img-grid.cols-3 { grid-template-columns: 1fr; }
  .img-grid.cols-4 { grid-template-columns: repeat(2, 1fr); }
  .scroll-to-top { right: 16px; bottom: 24px; width: 40px; height: 40px; font-size: 1.2em; }
}