/* ============================================================
   焕新科技 · 项目站
   设计参考：Altitude — 深色单色阶 + 单一蓝色 accent + 衬线标题
   ------------------------------------------------------------
   颜色只有一档色阶（#111 → #323232），蓝色 #2b7fff 仅用于链接与
   焦点环。标题用衬线、永不加粗；正文绝不用纯白 #ffffff。
   圆角只用 4 / 8 / 16。栅格 1200px，节奏 8/12/24/32/64/80。
   ============================================================ */

:root {
  /* 深色表面阶梯 */
  --obsidian: #111111;
  --canvas:   #181818;
  --card:     #1f1f1f;
  --slate:    #262626;
  --iron:     #323232;

  /* 唯一的强调色 */
  --accent: #2b7fff;

  /* 文字 */
  --text:  #eeeeee;
  --muted: #a4a19b;
  --faint: #5e5d59;

  /* 描边与阴影 */
  --line:        rgba(164, 161, 155, .16);
  --line-strong: rgba(164, 161, 155, .28);
  --whisper:     0 1px 2px rgba(0, 0, 0, .05);

  /* 字体：留了 Libre Baskerville / Inter 的位置，未加载时回落到系统衬线 / 无衬线 */
  --serif: "Libre Baskerville", Georgia, "Iowan Old Style", "Palatino Linotype",
           "Songti SC", SimSun, "Noto Serif CJK SC", serif;
  --sans:  "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
           "Hiragino Sans GB", "Microsoft YaHei", Arial, sans-serif;
  --mono:  "SFMono-Regular", "Cascadia Mono", Consolas, "Liberation Mono", Menlo, monospace;

  --maxw: 1200px;
  --r-sm: 4px;
  --r-md: 8px;
  --r-lg: 16px;

  /* 正文可读宽度：中文一行约 48 个汉字 */
  --measure: 760px;
}

/* 英文行太长不好读，收窄一些；标题同理，22ch 对英文太窄 */
:lang(en) { --measure: 640px; }
:lang(en) h1 { max-width: 18em; letter-spacing: -.02em; }

* { box-sizing: border-box; }

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  background: var(--canvas);
  color: var(--text);
  font-family: var(--sans);
  font-size: 15px;
  line-height: 1.85;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

a { color: inherit; text-decoration: none; }
a.link { color: var(--accent); }
a.link:hover { text-decoration: underline; text-underline-offset: 3px; }

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

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

.sr-only {
  position: absolute; width: 1px; height: 1px;
  padding: 0; margin: -1px; overflow: hidden;
  clip: rect(0 0 0 0); white-space: nowrap; border: 0;
}

/* 空占位符隐藏：某些板块某个语言没有那一句时，模板里留的是空元素 */
.stack > :empty,
.features > :empty { display: none; }

/* ------------------------------------------------------------
   导航
   ------------------------------------------------------------ */

.nav {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(24, 24, 24, .72);
  -webkit-backdrop-filter: blur(14px) saturate(1.2);
  backdrop-filter: blur(14px) saturate(1.2);
  border-bottom: 1px solid transparent;
  transition: border-color .35s ease, background .35s ease;
}
.nav.is-scrolled {
  border-bottom-color: var(--line);
  background: rgba(24, 24, 24, .92);
}

.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  height: 64px;
}

.brand { display: flex; align-items: center; gap: 10px; min-width: 0; }
.brand svg { display: block; flex: none; }
.brand-name {
  font-size: 14px;
  letter-spacing: .02em;
  white-space: nowrap;
}
.brand-sub {
  font-family: var(--mono);
  font-size: 10.5px;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--faint);
  padding-left: 10px;
  border-left: 1px solid var(--line-strong);
  white-space: nowrap;
}

.nav-links { display: flex; align-items: center; gap: 28px; }
.nav-links a {
  font-size: 14px;
  color: var(--muted);
  transition: color .2s ease;
}
.nav-links a:hover { color: var(--text); }

.lang {
  display: flex;
  gap: 2px;
  padding: 2px;
  border: 1px solid var(--line);
  border-radius: var(--r-sm);
}
.lang .lang-btn {
  appearance: none;
  border: 0;
  background: transparent;
  color: var(--faint);
  font-family: inherit;
  font-size: 12px;
  letter-spacing: .06em;
  padding: 4px 9px;
  border-radius: 3px;
  cursor: pointer;
  transition: background .2s ease, color .2s ease;
}
.lang .lang-btn:hover { color: var(--muted); }
.lang .lang-btn.is-active { background: var(--slate); color: var(--text); }

/* ------------------------------------------------------------
   Hero
   ------------------------------------------------------------ */

.hero { position: relative; overflow: hidden; padding: 104px 0 0; }
.hero .wrap { position: relative; z-index: 2; }

/* 山影 + 1px 山脊线：替代参考站里的山水摄影 */
.hero-ridge {
  position: absolute;
  inset: 0;
  z-index: 0;
  pointer-events: none;
}
.hero-ridge svg { position: absolute; inset: 0; width: 100%; height: 100%; }

.eyebrow {
  margin: 0 0 28px;
  font-family: var(--mono);
  font-size: 11.5px;
  letter-spacing: .16em;
  color: var(--muted);
}

h1 {
  margin: 0 0 28px;
  font-family: var(--serif);
  font-weight: 400;
  font-size: clamp(32px, 4.8vw, 58px);
  line-height: 1.22;
  letter-spacing: -.01em;
  max-width: 22ch;
}

.lede {
  margin: 0 0 36px;
  max-width: 62ch;
  font-size: 16.5px;
  line-height: 1.9;
  color: var(--muted);
}
.lede p { margin: 0 0 12px; }
.lede p:last-child { margin-bottom: 0; }

.cta-row { display: flex; flex-wrap: wrap; align-items: center; gap: 20px; }

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 18px;
  border: 1px solid var(--line-strong);
  border-radius: var(--r-sm);
  font-size: 14px;
  color: var(--text);
  transition: background .2s ease, border-color .2s ease, transform .2s ease;
}
.btn:hover { background: var(--card); border-color: var(--muted); }
.btn .arrow { transition: transform .25s ease; }
.btn:hover .arrow { transform: translateX(3px); }

.btn-text {
  display: inline-block;
  font-size: 14px;
  color: var(--muted);
  border-bottom: 1px solid var(--line-strong);
  padding-bottom: 2px;
  transition: color .2s ease, border-color .2s ease;
}
.btn-text:hover { color: var(--text); border-color: var(--muted); }

/* ------------------------------------------------------------
   区块骨架
   ------------------------------------------------------------ */

.section { padding: 104px 0; border-top: 1px solid var(--line); scroll-margin-top: 88px; }
.project,
.previews { scroll-margin-top: 88px; }

.section-head { max-width: var(--measure); margin-bottom: 56px; }
.section-eyebrow {
  margin: 0 0 18px;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: .2em;
  text-transform: uppercase;
  color: var(--faint);
}

h2 {
  margin: 0 0 20px;
  font-family: var(--serif);
  font-weight: 400;
  font-size: clamp(26px, 3.2vw, 38px);
  line-height: 1.3;
  letter-spacing: -.005em;
}

.section-head p { margin: 0 0 14px; color: var(--muted); font-size: 15.5px; }
.section-head p:last-child { margin-bottom: 0; }
.section-claim { color: var(--text) !important; font-size: 16.5px !important; }

/* 段落堆叠：模板里可能留有空元素，靠 :empty 隐藏 */
.stack { max-width: var(--measure); }
.stack p { margin: 0 0 16px; color: var(--muted); font-size: 15px; }
.stack p:last-child { margin-bottom: 0; }

.quote {
  font-family: var(--serif);
  font-size: 18px !important;
  line-height: 1.7;
  color: var(--text) !important;
}

.emphasis {
  color: var(--text) !important;
  padding-left: 18px;
  border-left: 1px solid var(--line-strong);
}

/* ------------------------------------------------------------
   三个产品预览
   ------------------------------------------------------------ */

.previews { padding-top: 88px; }

.preview-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 16px;
}

.preview {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--r-md);
  padding: 28px 28px 30px;
  transition: background .25s ease, border-color .25s ease;
}
.preview:hover { background: var(--slate); border-color: var(--line-strong); }

.preview-index {
  margin: 0 0 18px;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: .2em;
  color: var(--faint);
}

.preview-name {
  margin: 0 0 10px;
  font-family: var(--serif);
  font-size: 22px;
  line-height: 1.3;
}

.preview-claim {
  margin: 0 0 14px;
  font-size: 15px;
  line-height: 1.7;
  color: var(--text);
}

.preview-body {
  margin: 0;
  font-size: 14px;
  line-height: 1.85;
  color: var(--muted);
}

/* ------------------------------------------------------------
   产品区块（单栏）
   ------------------------------------------------------------ */

.project-head { margin-bottom: 64px; }

.proj-index {
  margin: 0 0 14px;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: .2em;
  color: var(--faint);
}

.proj-name {
  margin: 0 0 18px;
  font-family: var(--serif);
  font-weight: 400;
  font-size: clamp(30px, 3.8vw, 44px);
  line-height: 1.2;
}

.proj-claim {
  margin: 0 0 24px;
  max-width: 48ch;
  font-size: 17px;
  line-height: 1.8;
  color: var(--text);
}

.proj-intro { max-width: var(--measure); }

.project-body { max-width: var(--measure); }

.block { padding-top: 28px; border-top: 1px solid var(--line); }
.block + .block { margin-top: 40px; }

.block-title {
  margin: 0 0 20px;
  font-family: var(--serif);
  font-weight: 400;
  font-size: 21px;
  line-height: 1.5;
}

.block-cta { margin: 40px 0 0; }

/* 步骤（01–05） */
.steps { margin: 0; padding: 0; list-style: none; counter-reset: step; }
.steps li {
  display: grid;
  grid-template-columns: 40px minmax(0, 1fr);
  gap: 0 16px;
  padding: 18px 0;
  border-top: 1px solid var(--line);
}
.steps li:first-child { border-top: 0; padding-top: 0; }

.step-num {
  font-family: var(--mono);
  font-size: 11.5px;
  letter-spacing: .12em;
  color: var(--faint);
  padding-top: 3px;
}
.step-text { display: block; }
.step-title {
  display: block;
  font-size: 15.5px;
  color: var(--text);
  margin-bottom: 4px;
}
.step-body {
  display: block;
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--muted);
}

/* 特点列表 */
.features { margin: 0; padding: 0; list-style: none; }
.features li {
  position: relative;
  padding: 10px 0 10px 26px;
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--muted);
}
.features li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 21px;
  width: 12px;
  height: 1px;
  background: var(--line-strong);
}

/* ------------------------------------------------------------
   产品原则
   ------------------------------------------------------------ */

.principle-list {
  margin: 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--line);
}

.principle {
  display: grid;
  grid-template-columns: 40px minmax(0, 1fr);
  gap: 4px 16px;
  padding: 28px 0;
  border-bottom: 1px solid var(--line);
}

.principle-num {
  font-family: var(--mono);
  font-size: 11.5px;
  letter-spacing: .12em;
  color: var(--faint);
  padding-top: 6px;
}

.principle-title {
  margin: 0;
  font-family: var(--serif);
  font-weight: 400;
  font-size: 20px;
  line-height: 1.5;
}

.principle-claim {
  grid-column: 2;
  margin: 8px 0 0;
  font-size: 15px;
  line-height: 1.8;
  color: var(--text);
}

.principle-body {
  grid-column: 2;
  margin: 10px 0 0;
  max-width: var(--measure);
  font-size: 14.5px;
  line-height: 1.85;
  color: var(--muted);
}

/* ------------------------------------------------------------
   研发记录
   ------------------------------------------------------------ */

.record-list { border-top: 1px solid var(--line); }

.record {
  padding: 28px 0;
  border-bottom: 1px solid var(--line);
}

.record-title {
  margin: 0 0 16px;
  font-family: var(--serif);
  font-weight: 400;
  font-size: 20px;
  line-height: 1.5;
}

/* ------------------------------------------------------------
   联系
   ------------------------------------------------------------ */

.contact .wrap { max-width: var(--maxw); }
.contact-inner { max-width: 60ch; }
.contact h2 { margin-bottom: 22px; }
.contact .stack { margin-bottom: 24px; }
.contact .emphasis { margin: 0 0 32px; font-size: 16px; line-height: 1.8; }

/* ------------------------------------------------------------
   页脚
   ------------------------------------------------------------ */

.footer { border-top: 1px solid var(--line); padding: 72px 0 56px; }
.footer-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 40px;
  justify-content: space-between;
  align-items: flex-start;
}
.footer .brand { margin-bottom: 16px; }
.footer-tag { margin: 0 0 14px; max-width: 34ch; color: var(--muted); font-size: 14px; }
.footer-projects {
  margin: 0;
  font-family: var(--mono);
  font-size: 11.5px;
  letter-spacing: .16em;
  color: var(--faint);
  text-transform: uppercase;
}
.footer-links { display: flex; flex-wrap: wrap; gap: 12px 28px; }
.footer-links a { font-size: 14px; color: var(--muted); transition: color .2s ease; }
.footer-links a:hover { color: var(--text); }
.footer-meta {
  margin: 48px 0 0;
  padding-top: 24px;
  border-top: 1px solid var(--line);
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: .08em;
  color: var(--faint);
}

/* ------------------------------------------------------------
   内容列：统一限宽并居中，避免右侧空掉一大块
   ------------------------------------------------------------ */

.section-head,
.project-head,
.project-body,
.principle-list,
.record-list,
.contact-inner,
.block {
  max-width: var(--measure);
  margin-left: auto;
  margin-right: auto;
}

/* ------------------------------------------------------------
   入场动效（无 JS 时完全不动，内容照常可见）
   ------------------------------------------------------------ */

.js .reveal {
  opacity: 0;
  transform: translateY(14px);
  transition: opacity .8s ease, transform .8s cubic-bezier(.2, .6, .2, 1);
}
.js .reveal.is-in { opacity: 1; transform: none; }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .js .reveal { opacity: 1; transform: none; transition: none; }
  .preview, .btn, .btn .arrow { transition: none; }
}

/* ------------------------------------------------------------
   响应式
   ------------------------------------------------------------ */

@media (max-width: 900px) {
  .preview-grid { grid-template-columns: minmax(0, 1fr); }
}

@media (max-width: 860px) {
  .brand-sub { display: none; }
  .nav-links { gap: 18px; }
  .nav-links a { font-size: 13px; }
}

/* 窄屏：导航链接一个都不砍，靠收紧字距腾地方 */
@media (max-width: 560px) {
  .brand-name { display: none; }
  .nav-inner { gap: 12px; }
  .nav-links { gap: 12px; }
  .nav-links a { font-size: 12px; }
  .lang .lang-btn { padding: 4px 7px; }
}

@media (max-width: 720px) {
  .hero { padding-top: 72px; }
  .section { padding: 72px 0; }
  .previews { padding-top: 64px; }
  .section-head { margin-bottom: 40px; }
  .project-head { margin-bottom: 44px; }
  .preview { padding: 22px 20px 24px; }
  .steps li { grid-template-columns: 32px minmax(0, 1fr); gap: 0 12px; }
  .principle { grid-template-columns: 32px minmax(0, 1fr); gap: 4px 12px; }
  .footer { padding: 56px 0 40px; }
  .quote { font-size: 16.5px !important; }
}

/* 打印：白底黑字，别浪费纸 */
@media print {
  .nav, .hero-ridge { display: none; }
  body { background: #fff; color: #000; }
  .preview, .block, .record { border-color: #ddd; background: #fff; }
}