/* =========================================================
   深潜智力 deepdive intelligence — 官网样式 V1.0
   两套主题：浅湾 Shallows（默认浅色）/ 深海 Abyss（深色）
   主题由 <html data-theme="light|dark"> 控制；无脚本时跟随系统设置。
   ========================================================= */

/* ---------- 1. 设计变量 ---------- */
:root {
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB",
    "Microsoft YaHei UI", "Microsoft YaHei", "Noto Sans SC", "Noto Sans CJK SC", "Source Han Sans SC",
    "Helvetica Neue", Arial, sans-serif;
  --maxw: 1120px;
  --gutter: clamp(20px, 4vw, 40px);
  --header-h: 64px;
  --ease: cubic-bezier(.2, .7, .2, 1);

  /* 浅湾 Shallows */
  color-scheme: light;
  --bg: #f6fafc;
  --bg-alt: #edf5f8;
  --surface: #ffffff;
  --line: #d6e5ec;
  --line-strong: #b4ccd8;
  --text: #0b2236;
  --text-2: #3f5b74;
  --text-3: #577286;
  --accent: #077a7d;
  --accent-ink: #ffffff;
  --accent-tint: rgba(7, 122, 125, .08);
  --accent-soft: rgba(7, 122, 125, .32);
  --warn: #8a5d0c;
  --warn-tint: rgba(176, 124, 24, .12);
  --risk: #a83f32;
  --risk-tint: rgba(180, 72, 58, .10);
  --header-bg: rgba(246, 250, 252, .84);
  --veil: 246, 250, 252;
  --ray: rgba(255, 255, 255, .55);
}

/* 深海 Abyss：无脚本时跟随系统 */
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    color-scheme: dark;
    --bg: #031423;
    --bg-alt: #05192b;
    --surface: #0a2539;
    --line: rgba(130, 190, 215, .16);
    --line-strong: rgba(130, 190, 215, .30);
    --text: #e4eef4;
    --text-2: #a7bdcc;
    --text-3: #8aa3b4;
    --accent: #4cc9c4;
    --accent-ink: #02202a;
    --accent-tint: rgba(76, 201, 196, .10);
    --accent-soft: rgba(76, 201, 196, .40);
    --warn: #e6b862;
    --warn-tint: rgba(230, 184, 98, .13);
    --risk: #f09a8a;
    --risk-tint: rgba(240, 154, 138, .12);
    --header-bg: rgba(3, 20, 35, .80);
    --veil: 3, 20, 35;
    --ray: rgba(110, 222, 232, .22);
  }
}

/* 深海 Abyss：手动选择 */
:root[data-theme="dark"] {
  color-scheme: dark;
  --bg: #031423;
  --bg-alt: #05192b;
  --surface: #0a2539;
  --line: rgba(130, 190, 215, .16);
  --line-strong: rgba(130, 190, 215, .30);
  --text: #e4eef4;
  --text-2: #a7bdcc;
  --text-3: #8aa3b4;
  --accent: #4cc9c4;
  --accent-ink: #02202a;
  --accent-tint: rgba(76, 201, 196, .10);
  --accent-soft: rgba(76, 201, 196, .40);
  --warn: #e6b862;
  --warn-tint: rgba(230, 184, 98, .13);
  --risk: #f09a8a;
  --risk-tint: rgba(240, 154, 138, .12);
  --header-bg: rgba(3, 20, 35, .80);
  --veil: 3, 20, 35;
  --ray: rgba(110, 222, 232, .22);
}

/* ---------- 2. 基础 ---------- */
*, *::before, *::after { box-sizing: border-box; }

html {
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--header-h) + 16px);
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-sans);
  font-size: 17px;
  line-height: 1.8;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
  overflow-x: hidden;
}

/* 切换主题时的短暂过渡（由脚本添加，约 0.6 秒后移除） */
html.theme-fade, html.theme-fade *, html.theme-fade *::before, html.theme-fade *::after {
  transition: background-color .6s var(--ease), color .6s var(--ease), border-color .6s var(--ease) !important;
}

h1, h2, h3, h4 { margin: 0; font-weight: 600; color: var(--text); }
p { margin: 0; text-wrap: pretty; }
ul, ol { margin: 0; padding: 0; list-style: none; }
a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
  border-radius: 4px;
}

.skip-link {
  position: absolute;
  left: 16px;
  top: -48px;
  z-index: 100;
  padding: 8px 14px;
  background: var(--accent);
  color: var(--accent-ink);
  border-radius: 6px;
  font-size: 14px;
}
.skip-link:focus { top: 12px; }

.wrap {
  width: 100%;
  max-width: calc(var(--maxw) + var(--gutter) * 2);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.visually-hidden {
  position: absolute !important;
  width: 1px; height: 1px;
  overflow: hidden; clip: rect(0 0 0 0);
  white-space: nowrap;
}

/* ---------- 3. 页眉 ---------- */
.site-header {
  position: fixed;
  inset: 0 0 auto 0;
  z-index: 50;
  height: var(--header-h);
  border-bottom: 1px solid transparent;
  transition: background-color .3s var(--ease), border-color .3s var(--ease);
}
.site-header.is-scrolled,
.site-header.is-open {
  background: var(--header-bg);
  -webkit-backdrop-filter: saturate(1.3) blur(14px);
  backdrop-filter: saturate(1.3) blur(14px);
  border-bottom-color: var(--line);
}

.header-inner {
  height: 100%;
  display: flex;
  align-items: center;
  gap: 32px;
}

/* 文字标志（临时）。正式 Logo 到位后替换 .brand 内部即可。 */
.brand {
  display: inline-flex;
  align-items: baseline;
  gap: 12px;
  white-space: nowrap;
  margin-right: auto;
}
.brand-cn {
  font-size: 18px;
  font-weight: 700;
  letter-spacing: .12em;
  color: var(--text);
}
.brand-en {
  font-size: 13px;
  letter-spacing: .02em;
  color: var(--text-2);
}

.site-nav ul {
  display: flex;
  gap: 28px;
}
.site-nav a {
  font-size: 15px;
  color: var(--text-2);
  padding: 6px 0;
  border-bottom: 1px solid transparent;
  transition: color .2s, border-color .2s;
}
.site-nav a:hover { color: var(--text); }
.site-nav a[aria-current="true"] {
  color: var(--text);
  border-bottom-color: var(--accent);
}

/* 主题切换：浅湾 / 深海 */
.theme-switch {
  display: none;
  padding: 3px;
  border: 1px solid var(--line-strong);
  border-radius: 999px;
  background: rgba(var(--veil), .62);
  -webkit-backdrop-filter: blur(10px);
  backdrop-filter: blur(10px);
}
.js .theme-switch { display: inline-flex; }
.theme-switch button {
  appearance: none;
  border: 0;
  background: transparent;
  color: var(--text-2);
  font: inherit;
  font-size: 13px;
  line-height: 1;
  padding: 7px 12px;
  border-radius: 999px;
  cursor: pointer;
  transition: background-color .2s, color .2s;
}
.theme-switch button:hover { color: var(--text); }
.theme-switch button[aria-pressed="true"] {
  background: var(--accent-tint);
  color: var(--text);
  box-shadow: inset 0 0 0 1px var(--accent-soft);
}

.menu-toggle {
  display: none;
  appearance: none;
  border: 0;
  background: transparent;
  color: var(--text);
  width: 40px;
  height: 40px;
  margin-right: -8px;
  border-radius: 8px;
  cursor: pointer;
}
.menu-toggle span,
.menu-toggle span::before,
.menu-toggle span::after {
  display: block;
  width: 20px;
  height: 1.5px;
  margin-inline: auto;
  background: currentColor;
  border-radius: 1px;
  transition: transform .25s var(--ease), opacity .2s;
  position: relative;
}
.menu-toggle span::before,
.menu-toggle span::after { content: ""; position: absolute; left: 0; }
.menu-toggle span::before { top: -6px; }
.menu-toggle span::after { top: 6px; }
.is-open .menu-toggle span { background: transparent; }
.is-open .menu-toggle span::before { transform: translateY(6px) rotate(45deg); background: var(--text); }
.is-open .menu-toggle span::after { transform: translateY(-6px) rotate(-45deg); background: var(--text); }

/* ---------- 4. 按钮、标签、通用文字 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  height: 48px;
  padding: 0 24px;
  border-radius: 8px;
  font-size: 16px;
  font-weight: 500;
  letter-spacing: .02em;
  transition: background-color .2s, border-color .2s, color .2s, transform .2s;
}
.btn-primary {
  background: var(--accent);
  color: var(--accent-ink);
}
.btn-primary:hover { filter: brightness(1.08); }
.btn-ghost {
  border: 1px solid var(--line-strong);
  color: var(--text);
  background: rgba(var(--veil), .35);
}
.btn-ghost:hover { border-color: var(--accent); }

.tag {
  display: inline-block;
  font-size: 12.5px;
  line-height: 1;
  padding: 6px 10px;
  border: 1px solid var(--accent-soft);
  color: var(--accent);
  border-radius: 999px;
  letter-spacing: .04em;
  white-space: nowrap;
}

.chip {
  display: inline-block;
  font-size: 13px;
  line-height: 1;
  padding: 6px 9px;
  border-radius: 6px;
  font-weight: 500;
  white-space: nowrap;
}
.chip--ok { color: var(--accent); background: var(--accent-tint); }
.chip--warn { color: var(--warn); background: var(--warn-tint); }
.chip--risk { color: var(--risk); background: var(--risk-tint); }

/* ---------- 5. 首屏 ---------- */
.hero {
  position: relative;
  isolation: isolate;
  min-height: clamp(600px, 88vh, 820px);
  display: flex;
  align-items: center;
  padding: calc(var(--header-h) + 48px) 0 96px;
  overflow: hidden;
}

.hero-media {
  position: absolute;
  inset: 0;
  z-index: -1;
  pointer-events: none;
}
.hero-photo {
  position: absolute;
  inset: 0;
  background-size: cover;
  background-position: 72% 0%;
  background-repeat: no-repeat;
  opacity: 0;
  transition: opacity 1.2s var(--ease);
}
.hero-photo--shallows { background-image: url("../img/hero-shallows-1920.webp"); opacity: 1; }
.hero-photo--abyss { background-image: url("../img/hero-abyss-1920.webp"); }

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) .hero-photo--shallows { opacity: 0; }
  :root:not([data-theme="light"]) .hero-photo--abyss { opacity: 1; }
}
:root[data-theme="dark"] .hero-photo--shallows { opacity: 0; }
:root[data-theme="dark"] .hero-photo--abyss { opacity: 1; }

/* 让文字始终落在平静的底色上：左侧加纱，底部渐隐到页面底色 */
.hero-media::after {
  content: "";
  position: absolute;
  inset: 0;
  background:
    linear-gradient(180deg, rgba(var(--veil), .55) 0, rgba(var(--veil), 0) 150px),
    linear-gradient(90deg, rgba(var(--veil), .90) 0%, rgba(var(--veil), .66) 40%, rgba(var(--veil), 0) 74%),
    linear-gradient(180deg, rgba(var(--veil), 0) 52%, rgba(var(--veil), .7) 82%, rgb(var(--veil)) 100%);
}

/* 入射光：极缓慢地明暗呼吸 */
.hero-light {
  position: absolute;
  top: -30%;
  right: -12%;
  width: 72%;
  height: 110%;
  background: radial-gradient(closest-side, var(--ray), transparent 72%);
  animation: breathe 18s ease-in-out infinite;
}
@keyframes breathe {
  0%, 100% { opacity: .55; transform: translate3d(0, 0, 0); }
  50% { opacity: 1; transform: translate3d(-2%, 2%, 0); }
}

.hero-inner { position: relative; }
.hero h1 .keep { display: inline-block; }
.hero h1 {
  font-size: clamp(2.375rem, 1.2rem + 4.4vw, 4rem);
  line-height: 1.18;
  letter-spacing: .015em;
  max-width: 12em;
}
.hero-sub {
  margin-top: 28px;
  max-width: 33em;
  font-size: clamp(1.0625rem, .98rem + .4vw, 1.25rem);
  line-height: 1.8;
  color: var(--text-2);
}
.hero-sub .br-wide { display: none; }
@media (min-width: 900px) { .hero-sub .br-wide { display: inline; } }
.hero-actions {
  margin-top: 44px;
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}
.hero-focus {
  margin-top: 64px;
  font-size: 14px;
  color: var(--text-3);
  letter-spacing: .02em;
}

/* ---------- 6. 区块通用 ---------- */
.section {
  padding-block: clamp(72px, 9vw, 112px);
  border-top: 1px solid var(--line);
}
.section--flush { border-top: 0; padding-top: clamp(32px, 4vw, 48px); }

.section-head {
  max-width: 42em;
  margin-bottom: clamp(40px, 5vw, 64px);
}
.section-head h2 {
  font-size: clamp(1.75rem, 1.15rem + 2vw, 2.375rem);
  line-height: 1.3;
  letter-spacing: .01em;
}
.section-head p {
  margin-top: 18px;
  font-size: 1.0625rem;
  color: var(--text-2);
  text-wrap: balance;
}

.note {
  margin-top: 48px;
  font-size: 13.5px;
  color: var(--text-3);
}

/* ---------- 7. 01 问题：四个追问 ---------- */
.checks {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 0 32px;
  counter-reset: check;
}
.checks li {
  position: relative;
  padding-top: 28px;
  border-top: 1px solid var(--line-strong);
}
/* 追问按“对象 → 依据 → 规则 → 动作”递进，线上的刻度标出顺序 */
.checks li::before {
  counter-increment: check;
  content: counter(check);
  position: absolute;
  top: -13px;
  left: 0;
  width: 26px;
  height: 26px;
  border-radius: 50%;
  background: var(--bg);
  border: 1px solid var(--accent-soft);
  color: var(--accent);
  font-size: 13px;
  line-height: 24px;
  text-align: center;
  font-variant-numeric: tabular-nums;
}
.checks h3 {
  font-size: 1.1875rem;
  line-height: 1.5;
}
.checks p {
  margin-top: 10px;
  color: var(--text-2);
  font-size: 15.5px;
  line-height: 1.75;
}

.statement {
  margin-top: clamp(56px, 7vw, 88px);
  max-width: 30em;
  padding-left: 22px;
  border-left: 2px solid var(--accent);
  font-size: clamp(1.1875rem, 1rem + .9vw, 1.5rem);
  line-height: 1.7;
  font-weight: 500;
}

/* ---------- 8. 02 能力 ---------- */
.caps {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 48px;
}
.cap {
  padding-top: 28px;
  border-top: 1px solid var(--line-strong);
}
.cap h3 {
  font-size: 1.25rem;
  line-height: 1.5;
}
.cap > p {
  margin-top: 14px;
  color: var(--text-2);
  font-size: 16px;
}

.more-info { margin-top: 20px; }
.more-info summary {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  list-style: none;
  cursor: pointer;
  font-size: 14px;
  color: var(--accent);
  user-select: none;
}
.more-info summary::-webkit-details-marker { display: none; }
.more-info summary::after {
  content: "";
  width: 7px;
  height: 7px;
  border-right: 1.5px solid currentColor;
  border-bottom: 1.5px solid currentColor;
  transform: translateY(-2px) rotate(45deg);
  transition: transform .25s var(--ease);
}
.more-info[open] summary::after { transform: translateY(1px) rotate(-135deg); }
.more-info p {
  margin-top: 12px;
  padding: 14px 16px;
  background: var(--accent-tint);
  border-radius: 8px;
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--text-2);
}

/* ---------- 9. 03 实践 ---------- */
.case {
  display: grid;
  grid-template-columns: minmax(0, 5fr) minmax(0, 6fr);
  gap: clamp(32px, 5vw, 72px);
  align-items: start;
  padding-block: clamp(40px, 5vw, 56px);
  border-top: 1px solid var(--line);
}
.case:first-of-type { border-top: 0; padding-top: 0; }

.case-title {
  margin-top: 16px;
  font-size: clamp(1.375rem, 1.1rem + .9vw, 1.75rem);
  line-height: 1.4;
}
.case-text > p { margin-top: 16px; font-size: 16px; }
.case-text .lbl {
  font-weight: 600;
  color: var(--text);
  margin-right: .5em;
}
.case-approach { color: var(--text-2); }

.points {
  margin-top: 24px;
  display: grid;
  gap: 14px;
}
.points li {
  position: relative;
  padding-left: 20px;
  font-size: 15.5px;
  line-height: 1.75;
  color: var(--text-2);
}
.points li::before {
  content: "";
  position: absolute;
  left: 2px;
  top: .72em;
  width: 7px;
  height: 7px;
  border-radius: 50%;
  border: 1.5px solid var(--accent);
}
.points strong { color: var(--text); font-weight: 600; }

.case-text > p.case-bound {
  margin-top: 24px;
  padding-top: 16px;
  border-top: 1px dashed var(--line-strong);
  font-size: 15px;
  color: var(--text-2);
}

/* 示意面板：带边框的“展品”，左上角固定标注其性质 */
.demo {
  margin: 0;
  padding: 24px;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 12px;
  font-size: 15px;
  line-height: 1.7;
}
.demo-head {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
  padding-bottom: 16px;
  border-bottom: 1px dashed var(--line-strong);
}
.demo-title { font-weight: 600; font-size: 15px; }
.demo-flag {
  font-size: 12px;
  color: var(--text-3);
  border: 1px dashed var(--line-strong);
  padding: 3px 8px;
  border-radius: 4px;
  white-space: nowrap;
}
.demo-query {
  margin-top: 18px;
  color: var(--text);
}
.demo-qlabel {
  display: inline-block;
  margin-right: 10px;
  font-size: 12.5px;
  color: var(--text-3);
}
.demo-foot {
  margin-top: 18px;
  padding-top: 14px;
  border-top: 1px dashed var(--line-strong);
  font-size: 13px;
  line-height: 1.7;
  color: var(--text-3);
}

/* 资金路径：竖向，像一页对账单 */
.flow {
  margin-top: 20px;
  display: grid;
}
.flow-node {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 12px;
  padding: 10px 14px;
  border: 1px solid var(--line-strong);
  border-radius: 8px;
  background: var(--bg);
}
.node-name { font-weight: 600; }
.node-meta { font-size: 12.5px; color: var(--text-3); white-space: nowrap; }
.flow-node--end { border-style: dashed; }

.flow-edge {
  position: relative;
  display: flex;
  gap: 14px;
  align-items: center;
  min-height: 46px;
  padding-left: 46px;
  font-size: 14px;
  color: var(--text-2);
  font-variant-numeric: tabular-nums;
}
/* 竖线 + 箭头 */
.flow-edge::before {
  content: "";
  position: absolute;
  left: 26px;
  top: 0;
  bottom: 6px;
  width: 1.5px;
  background: var(--line-strong);
}
.flow-edge::after {
  content: "";
  position: absolute;
  left: 22.5px;
  bottom: 4px;
  width: 8px;
  height: 8px;
  border-right: 1.5px solid var(--line-strong);
  border-bottom: 1.5px solid var(--line-strong);
  transform: rotate(45deg);
}
.edge-time {
  font-weight: 600;
  color: var(--text);
  min-width: 3em;
}
.flow-edge--key::before { background: var(--accent); }
.flow-edge--key::after { border-color: var(--accent); }
.flow-edge--key .edge-time { color: var(--accent); }

.demo-result {
  margin: 20px 0 0;
  display: grid;
  gap: 10px;
}
.demo-result > div {
  display: grid;
  grid-template-columns: 3em 1fr;
  gap: 12px;
  align-items: baseline;
}
.demo-result dt { font-size: 12.5px; color: var(--text-3); }
.demo-result dd { margin: 0; }
.demo-result .chip { margin-left: 8px; vertical-align: 1px; }

/* 评标核查表 */
.bid-table {
  width: 100%;
  margin-top: 18px;
  border-collapse: collapse;
  font-size: 14.5px;
  line-height: 1.65;
}
.bid-table th {
  text-align: left;
  font-weight: 500;
  font-size: 12.5px;
  color: var(--text-3);
  padding: 0 12px 8px 0;
  border-bottom: 1px solid var(--line);
}
.bid-table td {
  padding: 14px 12px 14px 0;
  border-bottom: 1px solid var(--line);
  vertical-align: top;
}
.bid-table tr:last-child td { border-bottom: 0; }
.bid-table td:first-child { font-weight: 600; width: 30%; }
.bid-table td:nth-child(2) { color: var(--text-2); }
.bid-table td:last-child { padding-right: 0; text-align: right; white-space: nowrap; }

/* 可复用的能力方向 */
.more {
  margin-top: clamp(48px, 6vw, 72px);
  padding-top: clamp(40px, 5vw, 56px);
  border-top: 1px solid var(--line);
}
.more-head {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px 14px;
}
.more-head h3 { font-size: 1.25rem; }
.more-head p {
  flex-basis: 100%;
  color: var(--text-2);
  font-size: 15.5px;
}
.more-grid {
  margin-top: 32px;
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 32px;
}
.more-grid li {
  padding-top: 20px;
  border-top: 1px solid var(--line-strong);
}
.more-grid h4 { font-size: 1.0625rem; line-height: 1.5; }
.more-grid p {
  margin-top: 10px;
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--text-2);
}

/* ---------- 10. 04 方法 ---------- */
.arch {
  margin: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr) 176px;
  gap: 16px;
}
.arch-stack { display: grid; }

.layer {
  display: grid;
  grid-template-columns: 13em minmax(0, 1fr);
  gap: 8px 24px;
  align-items: baseline;
  padding: 16px 20px;
  border: 1px solid var(--line-strong);
  border-radius: 10px;
  background: var(--surface);
}
.layer h3 { font-size: 16px; line-height: 1.5; }
.layer p { font-size: 14.5px; color: var(--text-2); line-height: 1.7; }
/* 业务对象层是整张图的锚点，唯一的强调 */
.layer--core {
  border: 1.5px solid var(--accent);
  background: var(--accent-tint);
}
.layer--core h3 { color: var(--accent); }

.arch-group {
  position: relative;
  display: grid;
  padding: 36px 16px 16px;
  border: 1px dashed var(--line-strong);
  border-radius: 14px;
}
.arch-group-label {
  position: absolute;
  top: 9px;
  left: 18px;
  font-size: 12.5px;
  color: var(--text-3);
}

.arch-arrow {
  position: relative;
  height: 28px;
}
.arch-arrow::before {
  content: "";
  position: absolute;
  left: 50%;
  top: 4px;
  bottom: 4px;
  width: 1.5px;
  margin-left: -.75px;
  background: var(--line-strong);
}
.arch-arrow::after {
  content: "";
  position: absolute;
  left: 50%;
  bottom: 4px;
  width: 7px;
  height: 7px;
  margin-left: -3.5px;
  border-right: 1.5px solid var(--line-strong);
  border-bottom: 1.5px solid var(--line-strong);
  transform: rotate(45deg);
}
.arch-arrow--both > span {
  position: absolute;
  left: 50%;
  top: 4px;
  width: 7px;
  height: 7px;
  margin-left: -3.5px;
  border-left: 1.5px solid var(--line-strong);
  border-top: 1.5px solid var(--line-strong);
  transform: rotate(45deg);
}

.arch-rail {
  display: flex;
  flex-direction: column;
  padding: 18px 16px;
  border-radius: 10px;
  background: var(--bg-alt);
  border: 1px solid var(--line);
}
.arch-rail h3 {
  font-size: 13px;
  font-weight: 500;
  color: var(--text-3);
}
.arch-rail ul {
  flex: 1;
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 28px;
  margin-top: 12px;
}
.arch-rail li {
  font-size: 15px;
  font-weight: 500;
  padding-left: 14px;
  border-left: 2px solid var(--line-strong);
}
.arch figcaption {
  grid-column: 1 / -1;
  margin-top: 8px;
  font-size: 13.5px;
  color: var(--text-3);
}

.method-lower {
  margin-top: clamp(56px, 7vw, 88px);
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  gap: clamp(40px, 6vw, 80px);
}
.method-lower h3 { font-size: 1.25rem; }
.method-lower > div > p {
  margin-top: 20px;
  font-size: 15.5px;
  color: var(--text-2);
}

.chains { margin-top: 20px; display: grid; gap: 20px; }
.chains > li {
  padding-top: 16px;
  border-top: 1px solid var(--line);
}
.chains h4 { font-size: 16px; }
.chain-steps {
  margin-top: 6px;
  display: flex;
  flex-wrap: wrap;
  gap: 2px 0;
  font-size: 14.5px;
  color: var(--text-2);
}
.chain-steps li { white-space: nowrap; }
.chain-steps li:not(:last-child)::after {
  content: "→";
  margin: 0 .55em;
  color: var(--accent);
}

.fit-table {
  width: 100%;
  margin-top: 20px;
  border-collapse: collapse;
  font-size: 14.5px;
  line-height: 1.7;
}
.fit-table th, .fit-table td {
  text-align: left;
  vertical-align: top;
  padding: 14px 16px 14px 0;
  border-top: 1px solid var(--line);
}
.fit-table thead th {
  border-top: 0;
  padding-top: 0;
  padding-bottom: 8px;
  font-size: 12.5px;
  font-weight: 500;
  color: var(--text-3);
}
.fit-table tbody th { font-weight: 600; width: 38%; }
.fit-table td { color: var(--text-2); padding-right: 0; }

/* ---------- 11. 05 思考 ---------- */
.insights {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0 clamp(40px, 6vw, 80px);
}
.insights article {
  padding-block: 32px;
  border-top: 1px solid var(--line-strong);
}
.insights h3 {
  font-size: clamp(1.1875rem, 1rem + .6vw, 1.375rem);
  line-height: 1.55;
}
.insights p {
  margin-top: 12px;
  font-size: 15.5px;
  color: var(--text-2);
}

/* ---------- 12. 06 关于 ---------- */
.about {
  display: grid;
  grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
  gap: clamp(40px, 6vw, 88px);
}
.about-text p + p { margin-top: 20px; }
.about-text p { font-size: 16.5px; color: var(--text-2); }
.about-text p:first-child { color: var(--text); }
.about-name {
  margin-top: 36px !important;
  padding-top: 20px;
  border-top: 1px solid var(--line);
  font-size: 15px !important;
}
.principles h3 {
  font-size: 13px;
  font-weight: 500;
  color: var(--text-3);
}
.principles ul { margin-top: 8px; }
.principles li {
  padding-block: 18px;
  border-bottom: 1px solid var(--line);
}
.principles li:last-child { border-bottom: 0; }
.principles h4 { font-size: 17px; }
.principles p {
  margin-top: 6px;
  font-size: 15px;
  color: var(--text-2);
}

/* ---------- 13. 07 联系 ---------- */
.contact {
  background: var(--bg-alt);
}
.contact-inner {
  display: grid;
  grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
  gap: clamp(40px, 6vw, 88px);
  align-items: end;
}
.contact h2 {
  font-size: clamp(1.75rem, 1.15rem + 2vw, 2.375rem);
  line-height: 1.3;
}
.contact-inner > div > p {
  margin-top: 18px;
  color: var(--text-2);
  max-width: 34em;
}
.contact-list { margin: 0; display: grid; gap: 18px; }
.contact-list > div {
  padding-top: 14px;
  border-top: 1px solid var(--line-strong);
}
.contact-list dt { font-size: 13px; color: var(--text-3); }
.contact-list dd { margin: 4px 0 0; font-size: 17px; font-weight: 500; }

/* 联系方式占位：上线前必须替换，故意做得醒目 */
.tbd {
  display: inline-block;
  padding: 1px 8px;
  border: 1px dashed var(--warn);
  border-radius: 4px;
  color: var(--warn);
  font-size: .9em;
  font-weight: 500;
}

/* ---------- 14. 页脚 ---------- */
.site-footer {
  padding-block: 36px;
  border-top: 1px solid var(--line);
  font-size: 13.5px;
  color: var(--text-3);
}
.footer-inner {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 12px 32px;
}
.footer-brand { color: var(--text-2); }
.footer-brand b { font-weight: 600; color: var(--text); letter-spacing: .08em; margin-right: 10px; }

/* ---------- 15. 文章与详情页（模板使用） ---------- */
.page-head {
  padding: calc(var(--header-h) + 72px) 0 48px;
  border-bottom: 1px solid var(--line);
}
.page-head h1 {
  margin-top: 16px;
  font-size: clamp(2rem, 1.3rem + 2.6vw, 2.875rem);
  line-height: 1.3;
  max-width: 18em;
}
.page-head p { margin-top: 18px; max-width: 36em; color: var(--text-2); font-size: 1.0625rem; }
.page-head .page-tag { margin-top: 24px; }
.prose { max-width: 40em; padding-block: 56px 96px; }
.prose h2 { font-size: 1.5rem; margin-top: 56px; line-height: 1.4; }
.prose h3 { font-size: 1.1875rem; margin-top: 36px; }
.prose p, .prose ul, .prose ol { margin-top: 18px; color: var(--text); }
.prose ul { list-style: disc; padding-left: 1.4em; }
.prose ol { list-style: decimal; padding-left: 1.4em; }
.prose a { color: var(--accent); border-bottom: 1px solid var(--accent-soft); }
.back-link { font-size: 14px; color: var(--accent); }

.not-found {
  min-height: 100vh;
  display: grid;
  place-content: center;
  text-align: left;
  padding: var(--header-h) var(--gutter);
}
.not-found h1 { font-size: clamp(1.75rem, 1.2rem + 2vw, 2.5rem); }
.not-found p { margin-top: 14px; color: var(--text-2); }
.not-found .btn { margin-top: 32px; }

/* ---------- 16. 响应式 ---------- */
@media (max-width: 1080px) {
  .site-nav ul { gap: 22px; }
  .brand-en { display: none; }
  .checks { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 48px 32px; }
  .more-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (max-width: 960px) {
  .case { grid-template-columns: minmax(0, 1fr); }
  .caps { grid-template-columns: minmax(0, 1fr); gap: 40px; }
  .method-lower, .about, .contact-inner { grid-template-columns: minmax(0, 1fr); }
  .arch { grid-template-columns: minmax(0, 1fr); }
  .arch-rail ul { flex-direction: row; flex-wrap: wrap; justify-content: flex-start; gap: 10px 20px; }
  .layer { grid-template-columns: minmax(0, 1fr); gap: 4px; }
}

@media (max-width: 860px) {
  .menu-toggle { display: inline-flex; align-items: center; justify-content: center; }
  .header-inner { gap: 12px; }
  .site-nav {
    position: absolute;
    top: var(--header-h);
    left: 0;
    right: 0;
    display: none;
    background: var(--bg);
    border-bottom: 1px solid var(--line);
    box-shadow: 0 24px 48px -24px rgba(0, 0, 0, .25);
  }
  .is-open .site-nav { display: block; }
  .site-nav ul {
    flex-direction: column;
    gap: 0;
    padding: 8px var(--gutter) 16px;
  }
  .site-nav a {
    display: block;
    padding: 14px 0;
    font-size: 17px;
    color: var(--text);
    border-bottom: 1px solid var(--line);
  }
  .site-nav li:last-child a { border-bottom: 0; }
  .site-nav a[aria-current="true"] { border-bottom-color: var(--line); color: var(--accent); }
  /* 无脚本时直接展示导航，保证可用 */
  html:not(.js) .site-nav { position: static; display: block; background: none; border: 0; box-shadow: none; }
}

@media (max-width: 760px) {
  body { font-size: 16px; }
  .hero {
    min-height: auto;
    align-items: flex-end;
    padding: calc(var(--header-h) + 120px) 0 72px;
  }
  .hero-photo--shallows { background-image: url("../img/hero-shallows-1000.webp"); }
  .hero-photo--abyss { background-image: url("../img/hero-abyss-1000.webp"); }
  .hero-photo { background-position: 80% 0%; }
  .hero-media::after {
    background: linear-gradient(180deg, rgba(var(--veil), .15) 0%, rgba(var(--veil), .78) 38%, rgba(var(--veil), .94) 70%, rgb(var(--veil)) 100%);
  }
  .hero h1 { font-size: clamp(2.125rem, 1.3rem + 5vw, 2.75rem); }
  .hero-actions { flex-direction: column; align-items: stretch; }
  .hero-focus { margin-top: 40px; }
  .checks { grid-template-columns: minmax(0, 1fr); gap: 40px; }
  .more-grid, .insights { grid-template-columns: minmax(0, 1fr); }
  .more-grid { gap: 28px; }
  .demo { padding: 18px; }
  .demo-head { flex-wrap: wrap; }

  /* 评标表在手机上改为逐条卡片 */
  .bid-table thead { display: none; }
  .bid-table, .bid-table tbody, .bid-table tr, .bid-table td { display: block; width: auto; }
  .bid-table tr { padding: 14px 0; border-bottom: 1px solid var(--line); }
  .bid-table tr:last-child { border-bottom: 0; }
  .bid-table td { padding: 2px 0; border: 0; text-align: left !important; }
  .bid-table td:first-child { width: auto; }
  .bid-table td:last-child { margin-top: 8px; }

  .fit-table thead { display: none; }
  .fit-table, .fit-table tbody, .fit-table tr, .fit-table th, .fit-table td { display: block; width: auto !important; }
  .fit-table tr { padding: 14px 0; border-top: 1px solid var(--line); }
  .fit-table th, .fit-table td { border: 0; padding: 0; }
  .fit-table td { margin-top: 4px; }
}

@media (max-width: 400px) {
  .theme-switch button { padding: 7px 9px; }
  .brand-cn { font-size: 17px; letter-spacing: .08em; }
}

/* ---------- 17. 减少动态效果 ---------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .hero-light { animation: none; opacity: .8; }
  .hero-photo { transition: none; }
  html.theme-fade, html.theme-fade *, html.theme-fade *::before, html.theme-fade *::after { transition: none !important; }
}

/* ---------- 18. 打印 ---------- */
@media print {
  .site-header, .hero-media, .theme-switch, .menu-toggle { display: none !important; }
  .hero { min-height: auto; padding: 0 0 24px; }
  .section { padding-block: 24px; }
  .more-info p { background: none; padding: 0; }
  details.more-info > p { display: block; }
}