:root {
  --black: #1d1d1f;
  --white: #ffffff;
  --gray-bg: #f5f5f7;
  --gray-line: #d2d2d7;
  --gray-text: #6e6e73;
  --blue: #0a3d91;
  --red: #8c1c13;
  --radius: 18px;
  --maxw: 980px;
  --sidebar-w: 220px;
}

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

html { scroll-behavior: smooth; }

body {
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Display", "SF Pro Text",
    "PingFang SC", "Microsoft YaHei", "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  color: var(--black);
  background: var(--white);
  line-height: 1.5;
  display: flex;
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

.container { max-width: var(--maxw); margin: 0 auto; padding: 0 22px; }

/* ---------- 左侧导航 ---------- */
.sidebar {
  position: sticky; top: 0; align-self: flex-start; z-index: 100;
  width: var(--sidebar-w); flex: 0 0 var(--sidebar-w); height: 100vh;
  background: rgba(255, 255, 255, 0.9);
  backdrop-filter: saturate(180%) blur(18px);
  -webkit-backdrop-filter: saturate(180%) blur(18px);
  border-right: 1px solid var(--gray-line);
  padding: 30px 20px 24px;
  display: flex; flex-direction: column; gap: 4px;
  overflow-y: auto;
}
.side-brand {
  font-size: 24px; font-weight: 700; letter-spacing: -0.5px;
  color: var(--black); text-decoration: none; margin-bottom: 14px;
}
.lang-toggle {
  align-self: flex-start;
  border: 1px solid var(--gray-line); background: transparent; color: var(--gray-text);
  font-size: 12px; font-weight: 600; padding: 5px 13px; border-radius: 980px;
  cursor: pointer; transition: all 0.2s ease; margin-bottom: 22px;
}
.lang-toggle:hover { color: var(--black); border-color: var(--black); }

.side-nav { display: flex; flex-direction: column; gap: 2px; }
.side-nav a {
  position: relative; font-size: 14px; color: var(--gray-text);
  text-decoration: none; padding: 8px 10px; border-radius: 8px;
  transition: color 0.2s ease, background 0.2s ease;
}
.side-nav a:hover { color: var(--black); background: var(--gray-bg); }
.side-nav a.active { color: var(--blue); font-weight: 600; }
.side-nav a.active::before {
  content: ""; position: absolute; left: 0; top: 50%; transform: translateY(-50%);
  width: 3px; height: 16px; border-radius: 2px; background: var(--blue);
}
.side-root { font-weight: 600; color: var(--black) !important; }

/* 项目子导航 */
.side-sub { display: flex; flex-direction: column; gap: 0; margin: 2px 0 6px 10px; border-left: 1px solid var(--gray-line); }
.side-sub a {
  font-size: 12.5px; color: var(--gray-text); text-decoration: none;
  padding: 5px 0 5px 12px; line-height: 1.35; border-radius: 0;
  transition: color 0.2s ease;
}
.side-sub a:hover { color: var(--black); background: transparent; }
.side-sub a.active { color: var(--blue); font-weight: 600; }
.side-sub a.active::before { display: none; }

/* ---------- 主内容 ---------- */
.main { flex: 1 1 auto; min-width: 0; min-height: 100vh; }

/* ---------- HERO ---------- */
.hero { padding: 96px 0 88px; text-align: center; }
.monogram {
  width: 84px; height: 84px; margin: 0 auto 30px;
  border-radius: 50%; background: var(--blue); color: #fff;
  display: flex; align-items: center; justify-content: center;
  font-size: 40px; font-weight: 600;
}
.eyebrow { font-size: 14px; font-weight: 600; color: var(--red); letter-spacing: 0.4px; margin-bottom: 10px; }
.hero-name { font-size: clamp(56px, 8vw, 84px); font-weight: 700; letter-spacing: -1px; line-height: 1; }
.hero-title { font-size: clamp(19px, 3vw, 26px); font-weight: 600; margin-top: 16px; color: var(--black); }
.hero-sub { font-size: 16px; color: var(--gray-text); margin-top: 8px; }
.hero-tags { display: flex; flex-wrap: wrap; gap: 10px; justify-content: center; margin-top: 26px; }
.tag {
  font-size: 13px; font-family: "SF Mono", ui-monospace, "Cascadia Code", Menlo, Consolas, monospace;
  background: var(--gray-bg); color: var(--black);
  padding: 7px 14px; border-radius: 980px; border: 1px solid var(--gray-line);
}
.hero-cta { display: flex; gap: 14px; justify-content: center; margin-top: 34px; }

/* ---------- 按钮 ---------- */
.btn {
  display: inline-block; font-size: 15px; font-weight: 500;
  padding: 11px 24px; border-radius: 980px; text-decoration: none;
  transition: all 0.2s ease; cursor: pointer; border: 1px solid transparent;
}
.btn-primary { background: var(--blue); color: #fff; }
.btn-primary:hover { background: #08306f; }
.btn-ghost { background: transparent; color: var(--blue); border-color: var(--blue); }
.btn-ghost:hover { background: rgba(10, 61, 145, 0.06); }

/* ---------- 区块 ---------- */
.section { padding: 84px 0; scroll-margin-top: 24px; }
.section-alt { background: var(--gray-bg); }
.section-title { font-size: clamp(30px, 4.5vw, 42px); font-weight: 700; letter-spacing: -0.8px; text-align: center; margin-bottom: 40px; }
.lead { font-size: 19px; line-height: 1.7; max-width: 760px; margin: 0 auto; text-align: center; color: #333; }

/* ---------- 关于：特质 ---------- */
.traits { list-style: none; display: flex; flex-wrap: wrap; gap: 12px; justify-content: center; margin-top: 30px; }
.traits li {
  font-size: 14px; color: var(--gray-text);
  background: #fff; border: 1px solid var(--gray-line); padding: 8px 16px; border-radius: 980px;
}

/* ---------- 时间线 ---------- */
.timeline { max-width: 720px; margin: 0 auto; }
.tl-item { position: relative; padding: 0 0 34px 28px; border-left: 2px solid var(--gray-line); }
.tl-item:last-child { padding-bottom: 0; border-left-color: transparent; }
.tl-dot { position: absolute; left: -7px; top: 4px; width: 12px; height: 12px; border-radius: 50%; background: var(--blue); }
.tl-period { font-size: 13px; font-weight: 600; color: var(--red); letter-spacing: 0.3px; margin-bottom: 4px; }
.tl-head { font-size: 19px; font-weight: 600; margin-bottom: 4px; }
.tl-desc { font-size: 15px; color: var(--gray-text); }

/* ---------- 项目卡片 ---------- */
.proj-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 22px; }
.proj-card {
  background: #fff; border: 1px solid var(--gray-line); border-radius: var(--radius);
  overflow: hidden; display: flex; flex-direction: column;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
  scroll-margin-top: 24px;
}
.proj-card:hover { transform: translateY(-3px); box-shadow: 0 14px 34px rgba(0, 0, 0, 0.1); }
.proj-thumb { aspect-ratio: 16 / 10; background: #111; overflow: hidden; }
.proj-thumb img { width: 100%; height: 100%; object-fit: cover; display: block; transition: transform 0.4s ease; }
.proj-card:hover .proj-thumb img { transform: scale(1.04); }
.proj-body { padding: 24px 26px 26px; display: flex; flex-direction: column; gap: 12px; flex: 1; }
.proj-meta { font-size: 12.5px; font-weight: 600; color: var(--gray-text); letter-spacing: 0.2px; }
.proj-name { font-size: 21px; font-weight: 700; letter-spacing: -0.4px; }
.proj-desc { font-size: 15px; color: #38383d; line-height: 1.65; }
.proj-tags { display: flex; flex-wrap: wrap; gap: 8px; }
.proj-tags span {
  font-size: 12px; font-family: "SF Mono", ui-monospace, Menlo, Consolas, monospace;
  background: var(--gray-bg); color: var(--black); padding: 5px 11px; border-radius: 980px;
}
.proj-metric {
  margin-top: auto; font-size: 14px; font-weight: 600; color: var(--blue);
  border-top: 1px solid var(--gray-line); padding-top: 14px;
}

/* 突出项目：横向布局 */
.proj-card.feature { grid-column: 1 / -1; flex-direction: row; }
.proj-card.feature .proj-thumb { flex: 1.05; aspect-ratio: auto; min-height: 280px; }
.proj-card.feature .proj-body { flex: 1; justify-content: center; }

/* ---------- 技术栈 ---------- */
.skill-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 22px; }
.skill-card { background: #fff; border: 1px solid var(--gray-line); border-radius: var(--radius); padding: 26px; }
.skill-card h3 { font-size: 18px; font-weight: 700; margin-bottom: 14px; }
.skill-card ul { list-style: none; display: flex; flex-direction: column; gap: 9px; }
.skill-card li { font-size: 14px; color: #38383d; padding-left: 16px; position: relative; }
.skill-card li::before { content: ""; position: absolute; left: 0; top: 9px; width: 6px; height: 6px; border-radius: 50%; background: var(--blue); }

/* ---------- 联系 ---------- */
.contact-inner { text-align: center; }
.contact-list { list-style: none; margin: 30px auto; max-width: 460px; display: flex; flex-direction: column; gap: 14px; }
.contact-list li { display: flex; align-items: center; justify-content: center; gap: 12px; font-size: 17px; }
.c-label { color: var(--gray-text); font-size: 14px; }
.contact-list a { color: var(--blue); text-decoration: none; font-weight: 500; }
.contact-list a:hover { text-decoration: underline; }

.downloads { display: flex; gap: 14px; justify-content: center; flex-wrap: wrap; margin-top: 26px; }

/* ---------- 页脚 ---------- */
.footer { border-top: 1px solid var(--gray-line); padding: 26px 0; }
.footer span { font-size: 13px; color: var(--gray-text); display: block; text-align: center; }

/* ---------- 口令弹窗 ---------- */
.modal { position: fixed; inset: 0; z-index: 300; display: none; align-items: center; justify-content: center; padding: 20px; }
.modal.open { display: flex; }
.modal-backdrop { position: absolute; inset: 0; background: rgba(0, 0, 0, 0.5); }
.modal-card {
  position: relative; background: #fff; border-radius: 18px;
  padding: 30px; width: min(400px, 100%); box-shadow: 0 24px 60px rgba(0, 0, 0, 0.25);
}
.modal-card h3 { font-size: 19px; font-weight: 700; margin-bottom: 8px; }
.modal-hint { font-size: 13.5px; color: var(--gray-text); margin-bottom: 16px; line-height: 1.5; }
.modal-card input {
  width: 100%; font-size: 15px; padding: 11px 14px; border-radius: 10px;
  border: 1px solid var(--gray-line); outline: none; transition: border 0.2s ease;
  font-family: inherit;
}
.modal-card input:focus { border-color: var(--blue); }
.modal-error { color: var(--red); font-size: 13px; min-height: 18px; margin-top: 8px; }
.modal-actions { display: flex; gap: 12px; justify-content: flex-end; margin-top: 8px; }
.modal-actions .btn { padding: 9px 20px; font-size: 14px; }

/* ---------- 响应式 ---------- */
@media (max-width: 900px) {
  .proj-grid { grid-template-columns: 1fr; }
  .skill-grid { grid-template-columns: 1fr; }
}
@media (max-width: 600px) {
  body { flex-direction: column; }
  .sidebar {
    position: sticky; top: 0;
    flex: 0 0 auto; width: 100%; height: auto; align-self: stretch;
    flex-direction: row; align-items: center; gap: 14px;
    border-right: none; border-bottom: 1px solid var(--gray-line);
    padding: 12px 16px; overflow-x: auto; overflow-y: hidden;
  }
  .side-brand { font-size: 18px; margin: 0; flex-shrink: 0; }
  .lang-toggle { margin: 0; flex-shrink: 0; }
  .side-nav { flex-direction: row; gap: 4px; align-items: center; }
  .side-nav a { white-space: nowrap; padding: 6px 10px; }
  .side-nav a.active::before { display: none; }
  .side-sub { display: none; }
  .main { margin-left: 0; min-height: auto; }
  .section, .proj-card { scroll-margin-top: 76px; }
  .proj-card.feature { flex-direction: column; }
  .proj-card.feature .proj-thumb { min-height: 0; aspect-ratio: 16 / 10; }
}
@media (max-width: 768px) {
  .section { padding: 60px 0; }
  .hero { padding: 72px 0 64px; }
  .lead { font-size: 17px; }
}