/* ============================================================
   步天台 · 设计系统
   主题：夜观（深色，默认） / 澄心（浅色）
   与观象斋的米黄朱红古典风刻意区分：深空底 + 天青辉光 + 编辑式栅格
   ============================================================ */

:root {
  --font-serif: "Songti SC", "Source Han Serif SC", "Noto Serif SC", "STSong", "SimSun", Georgia, serif;
  --font-sans: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB",
    "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  --font-mono: "SF Mono", "JetBrains Mono", Menlo, Consolas, monospace;

  --maxw: 1240px;
  --radius: 14px;
  --radius-sm: 8px;
  --speed: .28s cubic-bezier(.4, 0, .2, 1);
}

/* ---------- 夜观（深色） ---------- */
html[data-theme="dark"] {
  --bg: #080b14;
  --bg-1: #0d1220;
  --bg-2: #121a2c;
  --bg-3: #18223a;
  --line: #1e2942;
  --line-2: #2a3757;
  --ink: #e8eefc;
  --ink-2: #a9b6d4;
  --ink-3: #6d7c9e;
  --accent: #6cc6e8;
  --accent-2: #8d7bff;
  --gold: #d9b26a;
  --cinnabar: #e0685c;
  --jade: #5fcf9a;
  --shadow: 0 18px 48px rgba(0, 0, 0, .55);
  --glow: 0 0 0 1px rgba(108, 198, 232, .28), 0 8px 32px rgba(108, 198, 232, .12);
  --star: rgba(255, 255, 255, .55);
  --paper-tex: none;
}

/* ---------- 澄心（浅色） ---------- */
html[data-theme="light"] {
  --bg: #f6f4ef;
  --bg-1: #fffefb;
  --bg-2: #fffdf8;
  --bg-3: #f0ece2;
  --line: #e2ddd0;
  --line-2: #d2cbba;
  --ink: #1d2433;
  --ink-2: #4a5468;
  --ink-3: #7b8497;
  --accent: #1f7a8c;
  --accent-2: #5b4bd6;
  --gold: #a8791f;
  --cinnabar: #c0453a;
  --jade: #2f8f63;
  --shadow: 0 12px 32px rgba(60, 50, 30, .10);
  --glow: 0 0 0 1px rgba(31, 122, 140, .25), 0 8px 24px rgba(31, 122, 140, .10);
  --star: rgba(30, 40, 60, .25);
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--font-sans);
  font-size: 15px;
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
  transition: background var(--speed), color var(--speed);
  overflow-x: hidden;
}

/* 星空背景（深色主题才显示） */
html[data-theme="dark"] body::before {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 0;
  background-image:
    radial-gradient(1.4px 1.4px at 12% 18%, var(--star) 50%, transparent 51%),
    radial-gradient(1.1px 1.1px at 78% 12%, var(--star) 50%, transparent 51%),
    radial-gradient(1.6px 1.6px at 34% 62%, var(--star) 50%, transparent 51%),
    radial-gradient(1px 1px at 62% 82%, var(--star) 50%, transparent 51%),
    radial-gradient(1.3px 1.3px at 88% 58%, var(--star) 50%, transparent 51%),
    radial-gradient(1px 1px at 22% 88%, var(--star) 50%, transparent 51%),
    radial-gradient(1.2px 1.2px at 52% 34%, var(--star) 50%, transparent 51%),
    radial-gradient(900px 520px at 80% -8%, rgba(108, 198, 232, .10), transparent 60%),
    radial-gradient(700px 460px at 8% 8%, rgba(141, 123, 255, .09), transparent 60%);
  opacity: .85;
}

body > * { position: relative; z-index: 1; }

a { color: inherit; text-decoration: none; }

h1, h2, h3, h4 {
  font-family: var(--font-serif);
  font-weight: 600;
  letter-spacing: .02em;
  margin: 0;
  line-height: 1.3;
}

p { margin: 0 0 1em; }

.serif { font-family: var(--font-serif); }
.mono { font-family: var(--font-mono); }
.muted { color: var(--ink-3); }
.center { text-align: center; }

.wrap { width: min(var(--maxw), calc(100% - 48px)); margin-inline: auto; }

/* ======================= 顶栏 ======================= */
.topbar {
  position: sticky;
  top: 0;
  z-index: 60;
  backdrop-filter: blur(14px) saturate(1.4);
  background: color-mix(in srgb, var(--bg) 82%, transparent);
  border-bottom: 1px solid var(--line);
}

.topbar-in {
  display: flex;
  align-items: center;
  gap: 22px;
  height: 62px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-serif);
  font-size: 19px;
  letter-spacing: .18em;
  flex-shrink: 0;
}

.brand-mark {
  width: 30px; height: 30px;
  display: grid; place-items: center;
  border: 1px solid var(--line-2);
  border-radius: 50%;
  color: var(--accent);
  font-size: 15px;
  position: relative;
  flex-shrink: 0;
}

.brand-mark::after {
  content: "";
  position: absolute; inset: -5px;
  border: 1px dashed color-mix(in srgb, var(--accent) 40%, transparent);
  border-radius: 50%;
  animation: spin 26s linear infinite;
}

@keyframes spin { to { transform: rotate(360deg); } }

.nav { display: flex; gap: 4px; margin-left: auto; align-items: center; }

.nav a {
  padding: 7px 14px;
  border-radius: 999px;
  font-size: 14px;
  color: var(--ink-2);
  transition: var(--speed);
  white-space: nowrap;
}

.nav a:hover { color: var(--ink); background: var(--bg-2); }

.nav a.on {
  color: var(--accent);
  background: color-mix(in srgb, var(--accent) 12%, transparent);
}

.icon-btn {
  width: 34px; height: 34px;
  display: grid; place-items: center;
  border: 1px solid var(--line);
  background: transparent;
  color: var(--ink-2);
  border-radius: 50%;
  cursor: pointer;
  transition: var(--speed);
  flex-shrink: 0;
}

.icon-btn:hover { color: var(--accent); border-color: var(--accent); }

.burger { display: none; }

/* ======================= 通用块 ======================= */
section { padding: 76px 0; }

.eyebrow {
  font-size: 12px;
  letter-spacing: .3em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 14px;
}

.sec-head { margin-bottom: 38px; max-width: 720px; }
.sec-head h2 { font-size: clamp(26px, 3.4vw, 40px); margin-bottom: 12px; }
.sec-head p { color: var(--ink-2); font-size: 15.5px; margin: 0; }

.card {
  background: var(--bg-1);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 24px;
  transition: var(--speed);
}

.card.hover:hover {
  transform: translateY(-4px);
  border-color: color-mix(in srgb, var(--accent) 45%, var(--line));
  box-shadow: var(--glow);
}

.grid { display: grid; gap: 18px; }
.g2 { grid-template-columns: repeat(2, 1fr); }
.g3 { grid-template-columns: repeat(3, 1fr); }
.g4 { grid-template-columns: repeat(4, 1fr); }

.tag {
  display: inline-block;
  font-size: 12px;
  padding: 3px 10px;
  border-radius: 999px;
  border: 1px solid var(--line-2);
  color: var(--ink-3);
}

.tag.a { color: var(--accent); border-color: color-mix(in srgb, var(--accent) 42%, transparent); }
.tag.g { color: var(--gold); border-color: color-mix(in srgb, var(--gold) 42%, transparent); }
.tag.c { color: var(--cinnabar); border-color: color-mix(in srgb, var(--cinnabar) 42%, transparent); }

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 11px 22px;
  border-radius: 999px;
  border: 1px solid var(--line-2);
  background: var(--bg-2);
  color: var(--ink);
  font-size: 14px;
  cursor: pointer;
  transition: var(--speed);
  font-family: inherit;
}

.btn:hover { border-color: var(--accent); color: var(--accent); transform: translateY(-1px); }

.btn.primary {
  background: linear-gradient(120deg, var(--accent), var(--accent-2));
  color: #fff;
  border-color: transparent;
}

.btn.primary:hover { filter: brightness(1.1); color: #fff; }

.btn.sm { padding: 7px 15px; font-size: 13px; }

.arrow { transition: transform var(--speed); }
a:hover .arrow { transform: translateX(4px); }

/* ======================= 首页 Hero ======================= */
.hero { padding: 92px 0 64px; position: relative; }

.hero-in { display: grid; grid-template-columns: 1.05fr .95fr; gap: 56px; align-items: center; }

.hero h1 {
  font-size: clamp(38px, 6vw, 68px);
  line-height: 1.16;
  letter-spacing: .04em;
  margin-bottom: 22px;
}

.hero h1 em {
  font-style: normal;
  background: linear-gradient(100deg, var(--accent), var(--accent-2) 60%, var(--gold));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.hero p.lead { font-size: 16.5px; color: var(--ink-2); max-width: 520px; margin-bottom: 30px; }

.hero-cta { display: flex; gap: 12px; flex-wrap: wrap; }

.stats {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
  margin-top: 42px;
}

.stat { background: var(--bg-1); padding: 18px 20px; }
.stat b { display: block; font-family: var(--font-serif); font-size: 30px; color: var(--accent); line-height: 1.2; }
.stat span { font-size: 13px; color: var(--ink-3); }

/* 星盘装饰 */
.orrery { width: 100%; max-width: 420px; margin-inline: auto; display: block; }
.orrery .ring { animation: spin 60s linear infinite; transform-origin: 150px 150px; }
.orrery .ring.r2 { animation-duration: 38s; animation-direction: reverse; }
.orrery .ring.r3 { animation-duration: 22s; }

@media (prefers-reduced-motion: reduce) {
  .orrery .ring, .brand-mark::after { animation: none; }
}

/* ======================= 每日一卦 ======================= */
.daily {
  display: grid;
  grid-template-columns: 260px 1fr;
  gap: 34px;
  align-items: center;
  background: linear-gradient(140deg, var(--bg-2), var(--bg-1));
  border: 1px solid var(--line);
  border-radius: 20px;
  padding: 34px;
}

.hexagram { display: grid; gap: 11px; justify-items: center; }

.yao {
  width: 178px; height: 22px;
  display: flex; justify-content: space-between; align-items: center;
  position: relative;
}

.yao i {
  height: 7px;
  border-radius: 2px;
  background: linear-gradient(90deg, var(--accent), var(--accent-2));
  box-shadow: 0 0 14px color-mix(in srgb, var(--accent) 55%, transparent);
}

.yao.yang i { width: 100%; }
.yao.yin i { width: 43%; }
.yao.yin i:last-child { width: 43%; }
.yao.ch-yang i, .yao.ch-yin i { background: linear-gradient(90deg, var(--gold), var(--cinnabar)); }

.yao small {
  position: absolute; right: -34px;
  font-size: 11px; color: var(--cinnabar);
  font-family: var(--mono, var(--font-mono));
}

/* ======================= 术语 / 词条 ======================= */
.term-list { display: grid; gap: 12px; }

.term {
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  background: var(--bg-1);
  overflow: hidden;
}

.term summary {
  padding: 14px 18px;
  cursor: pointer;
  font-family: var(--font-serif);
  font-size: 16px;
  list-style: none;
  display: flex;
  align-items: center;
  gap: 10px;
  transition: var(--speed);
}

.term summary::-webkit-details-marker { display: none; }
.term summary:hover { background: var(--bg-2); }
.term summary::after { content: "+"; margin-left: auto; color: var(--ink-3); font-size: 18px; }
.term[open] summary::after { content: "−"; }
.term .body { padding: 0 18px 18px; color: var(--ink-2); font-size: 14.5px; border-top: 1px solid var(--line); padding-top: 14px; }
.term .body .quote { color: var(--gold); font-family: var(--font-serif); }

/* ======================= 书籍卡 ======================= */
.book-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(196px, 1fr)); gap: 20px; }

.book { cursor: pointer; transition: var(--speed); }

.book:hover { transform: translateY(-6px); }

.book-spine {
  height: 214px;
  border-radius: 10px 12px 12px 10px;
  background: linear-gradient(160deg, var(--bg-3), var(--bg-2));
  border: 1px solid var(--line-2);
  border-left: 4px solid var(--accent);
  display: flex; flex-direction: column; align-items: center; justify-content: center;
  gap: 10px;
  position: relative;
  overflow: hidden;
  box-shadow: var(--shadow);
}

.book:hover .book-spine { border-left-color: var(--gold); }

.book-spine .seal {
  width: 54px; height: 54px;
  display: grid; place-items: center;
  border: 1px solid color-mix(in srgb, var(--cinnabar) 60%, transparent);
  color: var(--cinnabar);
  border-radius: 6px;
  font-family: var(--font-serif);
  font-size: 13px;
  line-height: 1.1;
  text-align: center;
  letter-spacing: .04em;
  writing-mode: vertical-rl;
  padding: 4px;
}

.book-spine .t {
  font-family: var(--font-serif);
  font-size: 15px;
  color: var(--ink);
  text-align: center;
  padding: 0 12px;
}

.book-spine .d { font-size: 11.5px; color: var(--ink-3); letter-spacing: .12em; }

.book .meta { margin-top: 11px; }
.book .meta .n { font-family: var(--font-serif); font-size: 15px; display: block; }
.book .meta .c { font-size: 12px; color: var(--ink-3); }

/* ======================= 阅读器 ======================= */
.reader-wrap { display: grid; grid-template-columns: 232px 1fr; gap: 34px; align-items: start; }

.reader-body {
  background: var(--bg-1);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 44px 40px;
  min-height: 60vh;
}

.reader-body.vertical {
  writing-mode: vertical-rl;
  text-orientation: upright;
  height: 66vh;
  overflow-x: auto;
  overflow-y: hidden;
  font-size: var(--fs, 19px);
  line-height: 2.1;
  letter-spacing: .12em;
}

.reader-body.horizontal { font-size: var(--fs, 18px); line-height: 2.15; }

.reader-body h2.rd-title {
  font-size: calc(var(--fs, 18px) + 6px);
  margin-bottom: .9em;
  letter-spacing: .1em;
}

.reader-body.vertical h2.rd-title { margin-bottom: 0; margin-left: .9em; }

.rd-p { margin-bottom: 1.1em; text-indent: 2em; color: var(--ink); }
.reader-body.vertical .rd-p { text-indent: 0; margin-bottom: 0; }

.zi {
  color: var(--cinnabar);
  cursor: help;
  border-bottom: 1px dotted color-mix(in srgb, var(--cinnabar) 60%, transparent);
}

/* ======================= 表格 / 排盘 ======================= */
.panels { display: grid; grid-template-columns: 300px 1fr; gap: 26px; align-items: start; }

.panel {
  background: var(--bg-1);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 22px;
}

.field { margin-bottom: 15px; }
.field label { display: block; font-size: 12.5px; color: var(--ink-3); margin-bottom: 6px; letter-spacing: .05em; }

.field input, .field select, .field textarea {
  width: 100%;
  padding: 9px 12px;
  background: var(--bg-2);
  border: 1px solid var(--line-2);
  border-radius: var(--radius-sm);
  color: var(--ink);
  font-family: inherit;
  font-size: 14px;
  outline: none;
  transition: var(--speed);
}

.field input:focus, .field select:focus, .field textarea:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px color-mix(in srgb, var(--accent) 15%, transparent);
}

.pillar-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 12px; margin-bottom: 22px; }

.pillar {
  background: var(--bg-2);
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  padding: 16px 10px;
  text-align: center;
}

.pillar .lb { font-size: 11.5px; color: var(--ink-3); letter-spacing: .2em; margin-bottom: 8px; }

.pillar .gz {
  font-family: var(--font-serif);
  font-size: 27px;
  line-height: 1.25;
  letter-spacing: .06em;
}

.pillar .gz .t { color: var(--ink); }
.pillar .gz .b { color: var(--accent); }

.pillar .ss { margin-top: 9px; font-size: 13px; color: var(--gold); }
.pillar .cx { font-size: 11.5px; color: var(--ink-3); margin-top: 3px; }

table.tb { width: 100%; border-collapse: collapse; font-size: 14px; }
table.tb th, table.tb td { border: 1px solid var(--line); padding: 9px 11px; text-align: center; }
table.tb th { background: var(--bg-2); color: var(--ink-2); font-weight: 500; font-size: 13px; }
table.tb td.hl { color: var(--accent); font-family: var(--font-serif); font-size: 15px; }

.kv { display: grid; grid-template-columns: auto 1fr; gap: 8px 16px; font-size: 14px; }
.kv dt { color: var(--ink-3); }
.kv dd { margin: 0; }

/* 紫微命盘 */
.zw-pan { display: grid; grid-template-columns: repeat(4, 1fr); grid-template-rows: repeat(4, 1fr); gap: 4px; aspect-ratio: 1; max-width: 620px; margin-inline: auto; }

.zw-gong {
  border: 1px solid var(--line);
  background: var(--bg-1);
  padding: 7px;
  font-size: 11.5px;
  line-height: 1.6;
  position: relative;
  min-height: 108px;
}

.zw-gong .gn { position: absolute; top: 5px; left: 7px; font-size: 11px; color: var(--ink-3); }
.zw-gong .gx { position: absolute; top: 5px; right: 7px; font-size: 11px; color: var(--accent); }
.zw-gong .st { margin-top: 20px; text-align: center; font-family: var(--font-serif); font-size: 13px; }
.zw-gong .st .s { display: block; }
.zw-gong .st .s.mj { color: var(--gold); }
.zw-gong .st .s.hua-lu { color: var(--jade); }
.zw-gong .st .s.hua-ji { color: var(--cinnabar); }
.zw-gong.ming { border-color: var(--accent); background: color-mix(in srgb, var(--accent) 8%, var(--bg-1)); }
.zw-gong.shen { border-color: var(--cinnabar); }

/* 奇门盘 */
.qm-pan { display: grid; grid-template-columns: repeat(3, 1fr); gap: 6px; max-width: 560px; margin-inline: auto; }

.qm-gong {
  border: 1px solid var(--line);
  background: var(--bg-1);
  border-radius: var(--radius-sm);
  padding: 10px;
  min-height: 108px;
  font-size: 12px;
  line-height: 1.7;
}

.qm-gong .num { color: var(--ink-3); font-size: 11px; }
.qm-gong .shen { color: var(--accent-2); }
.qm-gong .star { color: var(--gold); font-family: var(--font-serif); }
.qm-gong .door { color: var(--jade); }
.qm-gong .qi { color: var(--ink); font-family: var(--font-serif); font-size: 14px; }

/* ======================= 图解卡 ======================= */
.chart-card {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--bg-1);
  padding: 20px;
  transition: var(--speed);
}

.chart-card:hover { transform: translateY(-4px); box-shadow: var(--glow); }
.chart-card svg { width: 100%; height: auto; display: block; }
.chart-card h3 { font-size: 16px; margin: 14px 0 6px; }
.chart-card p { font-size: 13px; color: var(--ink-3); margin: 0 0 10px; }

.tabs { display: flex; gap: 6px; flex-wrap: wrap; margin-bottom: 22px; }

.tab {
  padding: 7px 16px;
  border-radius: 999px;
  border: 1px solid var(--line-2);
  background: transparent;
  color: var(--ink-2);
  cursor: pointer;
  font-size: 13.5px;
  font-family: inherit;
  transition: var(--speed);
}

.tab:hover { color: var(--ink); border-color: var(--accent); }
.tab.on { background: var(--accent); color: #fff; border-color: transparent; }

.live { font-size: 12.5px; color: var(--accent); font-family: var(--font-mono); }

/* ======================= 文章 / 论坛 ======================= */
.post-row {
  display: grid;
  grid-template-columns: 92px 1fr auto;
  gap: 20px;
  padding: 22px 0;
  border-top: 1px solid var(--line);
  align-items: center;
  transition: var(--speed);
}

.post-row:hover { padding-left: 10px; }
.post-row .date { font-family: var(--font-mono); font-size: 12.5px; color: var(--ink-3); }
.post-row .date b { display: block; font-family: var(--font-serif); font-size: 22px; color: var(--ink); }
.post-row h3 { font-size: 19px; margin-bottom: 5px; }
.post-row p { font-size: 13.5px; color: var(--ink-3); margin: 0; }

.thread { border: 1px solid var(--line); border-radius: var(--radius); padding: 18px 20px; background: var(--bg-1); }
.thread h4 { font-size: 16px; margin-bottom: 6px; }
.thread .m { font-size: 12px; color: var(--ink-3); display: flex; gap: 12px; margin-top: 10px; }

.empty { text-align: center; padding: 54px 20px; color: var(--ink-3); border: 1px dashed var(--line-2); border-radius: var(--radius); }

/* ======================= 页脚 ======================= */
footer {
  border-top: 1px solid var(--line);
  padding: 54px 0 40px;
  margin-top: 40px;
  background: var(--bg-1);
}

.foot-brand {
  font-family: var(--font-serif);
  font-size: 30px;
  letter-spacing: .5em;
  text-align: center;
  color: var(--ink-3);
  margin-bottom: 26px;
}

.foot-note { font-size: 12.5px; color: var(--ink-3); line-height: 1.9; max-width: 780px; margin-inline: auto; text-align: center; }

.disclaimer {
  margin-top: 22px;
  padding: 14px 18px;
  border: 1px solid color-mix(in srgb, var(--cinnabar) 30%, var(--line));
  border-radius: var(--radius-sm);
  font-size: 12.5px;
  color: var(--ink-2);
  background: color-mix(in srgb, var(--cinnabar) 6%, transparent);
}

/* ======================= 响应式 ======================= */
@media (max-width: 980px) {
  .hero-in { grid-template-columns: 1fr; gap: 34px; }
  .orrery { max-width: 300px; }
  .daily { grid-template-columns: 1fr; }
  .panels, .reader-wrap { grid-template-columns: 1fr; }
  .g4 { grid-template-columns: repeat(2, 1fr); }
  .g3 { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 720px) {
  .wrap { width: calc(100% - 32px); }
  section { padding: 54px 0; }
  .burger { display: grid; }

  .nav {
    position: fixed;
    inset: 62px 0 auto 0;
    flex-direction: column;
    align-items: stretch;
    background: var(--bg-1);
    border-bottom: 1px solid var(--line);
    padding: 14px 20px 20px;
    gap: 2px;
    transform: translateY(-130%);
    transition: transform var(--speed);
    margin: 0;
  }

  .nav.open { transform: none; }
  .nav a { padding: 11px 14px; border-radius: var(--radius-sm); }
  .g2, .g3, .g4 { grid-template-columns: 1fr; }
  .stats { grid-template-columns: 1fr; }
  .pillar-grid { grid-template-columns: repeat(2, 1fr); }
  .book-grid { grid-template-columns: repeat(auto-fill, minmax(150px, 1fr)); }
  .post-row { grid-template-columns: 1fr; gap: 8px; }
  .zw-pan { max-width: 100%; }
}

.reveal { opacity: 0; transform: translateY(18px); transition: opacity .7s ease, transform .7s ease; }
.reveal.in { opacity: 1; transform: none; }