/* ═══════════════════════════════════════════════════════════════
   stevenszk.com — 全站共享样式（零外部依赖）
   ═══════════════════════════════════════════════════════════════ */

/* ═══════════ 设计变量（浅色 / 深色两套）═══════════ */
:root {
  --bg: #ffffff;
  --bg-soft: #f5f7fa;
  --card: #ffffff;
  --text: #171c26;
  --muted: #5b6472;
  --accent: #2563eb;
  --accent-strong: #1d4ed8;
  --accent-soft: rgba(37, 99, 235, 0.09);
  --border: #e4e8ef;
  --shadow: 0 1px 2px rgba(23, 28, 38, .04), 0 8px 24px rgba(23, 28, 38, .06);
  --shadow-lg: 0 4px 8px rgba(23, 28, 38, .06), 0 16px 40px rgba(23, 28, 38, .12);
  --nav-bg: rgba(255, 255, 255, .82);
}
:root[data-theme="dark"] {
  --bg: #0e1116;
  --bg-soft: #141922;
  --card: #161c26;
  --text: #e8ebf1;
  --muted: #99a3b1;
  --accent: #6aa9ff;
  --accent-strong: #8ab8ff;
  --accent-soft: rgba(106, 169, 255, 0.12);
  --border: #262e3b;
  --shadow: 0 1px 2px rgba(0, 0, 0, .25), 0 8px 24px rgba(0, 0, 0, .25);
  --shadow-lg: 0 4px 8px rgba(0, 0, 0, .3), 0 16px 40px rgba(0, 0, 0, .4);
  --nav-bg: rgba(14, 17, 22, .82);
}

/* ═══════════ 基础 ═══════════ */
* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial,
               "PingFang SC", "Microsoft YaHei", sans-serif;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  transition: background .3s ease, color .3s ease;
}
a { color: var(--accent); text-decoration: none; }
a:hover { color: var(--accent-strong); }
img { max-width: 100%; display: block; }
.container { max-width: 1060px; margin: 0 auto; padding: 0 24px; }
section { padding: 76px 0 88px; scroll-margin-top: 70px; }
.section-alt { background: var(--bg-soft); }

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

.skip-link {
  position: absolute; left: -9999px; top: 0; z-index: 100;
  background: var(--accent); color: #fff; padding: 10px 18px; border-radius: 0 0 8px 0;
}
.skip-link:focus { left: 0; }

/* ═══════════ 区块 / 页面标题 ═══════════ */
.section-head { margin-bottom: 44px; }
.section-head .kicker {
  display: inline-block; font-size: .78rem; font-weight: 700;
  letter-spacing: .14em; text-transform: uppercase; color: var(--accent);
  margin-bottom: 8px;
}
.section-head h2 { font-size: clamp(1.7rem, 3.2vw, 2.15rem); line-height: 1.25; letter-spacing: -.01em; }
.section-head h1 { font-size: clamp(2.1rem, 4.5vw, 2.75rem); line-height: 1.15; letter-spacing: -.02em; }
.section-head .sub { color: var(--muted); margin-top: 10px; max-width: 620px; }

/* ═══════════ 导航栏 ═══════════ */
nav {
  position: sticky; top: 0; z-index: 50;
  background: var(--nav-bg);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
}
.nav-inner { display: flex; align-items: center; justify-content: space-between; height: 62px; }
.logo { font-weight: 800; font-size: 1.05rem; color: var(--text); letter-spacing: -.01em; }
.logo span { color: var(--accent); }
.nav-right { display: flex; align-items: center; gap: 6px; }
.nav-links { display: flex; align-items: center; gap: 2px; }
.nav-links a {
  color: var(--muted); font-size: .92rem; font-weight: 500;
  padding: 7px 13px; border-radius: 8px; transition: color .2s, background .2s;
}
.nav-links a:hover { color: var(--text); background: var(--accent-soft); }
.nav-links a.active { color: var(--accent-strong); background: var(--accent-soft); font-weight: 600; }
.nav-links a.cv-link {
  color: var(--accent-strong); border: 1px solid var(--accent);
  margin-left: 8px; padding: 6px 16px; border-radius: 999px; font-weight: 600;
}
.nav-links a.cv-link:hover, .nav-links a.cv-link.active { background: var(--accent); color: #fff; }

.icon-btn {
  display: inline-flex; align-items: center; justify-content: center;
  width: 38px; height: 38px; border-radius: 9px;
  border: 1px solid var(--border); background: transparent; color: var(--muted);
  cursor: pointer; transition: color .2s, border-color .2s, background .2s;
}
.icon-btn:hover { color: var(--accent); border-color: var(--accent); }
.icon-btn svg { width: 18px; height: 18px; }
#themeToggle .sun { display: none; }
:root[data-theme="dark"] #themeToggle .sun { display: block; }
:root[data-theme="dark"] #themeToggle .moon { display: none; }
.menu-btn { display: none; }

@media (max-width: 900px) {
  .menu-btn { display: inline-flex; }
  .nav-links {
    display: none; position: absolute; top: 100%; left: 0; right: 0;
    flex-direction: column; align-items: stretch; gap: 4px;
    background: var(--nav-bg); backdrop-filter: blur(14px); -webkit-backdrop-filter: blur(14px);
    border-bottom: 1px solid var(--border); padding: 14px 20px 20px;
  }
  .nav-links.open { display: flex; }
  .nav-links a { padding: 11px 14px; }
  .nav-links a.cv-link { margin-left: 0; text-align: center; }
}

/* ═══════════ Hero（首页）═══════════ */
.hero {
  position: relative; overflow: hidden;
  display: flex; align-items: center;
  min-height: min(78vh, 720px);
  padding: 80px 0;
}
.hero::before {
  content: ""; position: absolute; inset: 0; pointer-events: none;
  background:
    radial-gradient(600px 320px at 85% 8%, var(--accent-soft), transparent 70%),
    radial-gradient(500px 300px at 8% 95%, var(--accent-soft), transparent 70%);
}
.hero .container { position: relative; }
.hero .kicker { color: var(--accent); font-weight: 600; font-size: 1.02rem; margin-bottom: 14px; }
.hero h1 {
  font-size: clamp(2.5rem, 6.5vw, 4rem); line-height: 1.08;
  letter-spacing: -.025em; margin-bottom: 14px;
}
.hero h1 .grad {
  background: linear-gradient(100deg, var(--accent), #7c3aed);
  -webkit-background-clip: text; background-clip: text; color: transparent;
}
.hero .tagline {
  font-size: clamp(1.3rem, 3vw, 1.7rem); font-weight: 600;
  color: var(--muted); letter-spacing: -.01em; margin-bottom: 22px;
}
.hero .intro { max-width: 600px; color: var(--muted); font-size: 1.05rem; margin-bottom: 34px; }
.hero-cta { display: flex; gap: 14px; flex-wrap: wrap; align-items: center; margin-bottom: 34px; }

.btn {
  display: inline-flex; align-items: center; gap: 9px;
  padding: 12px 24px; border-radius: 10px;
  font-size: .95rem; font-weight: 600; cursor: pointer;
  border: 1px solid transparent;
  transition: transform .18s ease, box-shadow .18s ease, background .2s, color .2s, border-color .2s;
}
.btn svg { width: 17px; height: 17px; }
.btn-primary { background: var(--accent); color: #fff; }
.btn-primary:hover { background: var(--accent-strong); color: #fff; transform: translateY(-2px); box-shadow: var(--shadow-lg); }
.btn-ghost { border-color: var(--border); color: var(--text); background: var(--card); }
.btn-ghost:hover { border-color: var(--accent); color: var(--accent); transform: translateY(-2px); }

.social-row { display: flex; gap: 10px; }
.social-row a {
  display: inline-flex; align-items: center; justify-content: center;
  width: 42px; height: 42px; border-radius: 10px;
  border: 1px solid var(--border); color: var(--muted); background: var(--card);
  transition: color .2s, border-color .2s, transform .18s ease;
}
.social-row a:hover { color: var(--accent); border-color: var(--accent); transform: translateY(-2px); }
.social-row svg { width: 19px; height: 19px; }

/* ═══════════ 首页快捷入口卡片 ═══════════ */
.quick { padding: 0 0 96px; }
.quick-grid {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(185px, 1fr)); gap: 16px;
}
.quick-card {
  display: flex; flex-direction: column; gap: 5px;
  background: var(--card); border: 1px solid var(--border); border-radius: 16px;
  padding: 22px 22px 18px; color: var(--text); box-shadow: var(--shadow);
  transition: transform .18s ease, box-shadow .18s ease, border-color .2s;
}
.quick-card:hover { transform: translateY(-4px); border-color: var(--accent); box-shadow: var(--shadow-lg); color: var(--text); }
.quick-card .q-emoji { font-size: 1.55rem; margin-bottom: 4px; }
.quick-card h2 { font-size: 1.02rem; letter-spacing: -.01em; }
.quick-card p { color: var(--muted); font-size: .85rem; line-height: 1.55; flex: 1; }
.quick-card .q-arrow { color: var(--accent); font-weight: 700; margin-top: 8px; transition: transform .18s ease; }
.quick-card:hover .q-arrow { transform: translateX(4px); }

/* ═══════════ About ═══════════ */
.about-grid { display: grid; grid-template-columns: 190px 1fr; gap: 44px; align-items: start; }
@media (max-width: 760px) {
  .about-grid { grid-template-columns: 1fr; }
  .avatar-wrap { margin: 0 auto; }
}
.avatar-wrap { text-align: center; }
.avatar {
  width: 170px; height: 170px; border-radius: 26px;
  background: linear-gradient(135deg, var(--accent), #7c3aed);
  color: #fff; font-size: 3.4rem; font-weight: 800; letter-spacing: .02em;
  display: flex; align-items: center; justify-content: center;
  box-shadow: var(--shadow-lg);
}
.avatar-img { width: 170px; height: 170px; border-radius: 26px; object-fit: cover; box-shadow: var(--shadow-lg); }
.about-text p { margin-bottom: 16px; color: var(--muted); font-size: 1.02rem; }
.about-text p strong { color: var(--text); }
.facts { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 22px; }
.fact {
  display: inline-flex; align-items: center; gap: 7px;
  font-size: .88rem; font-weight: 500; color: var(--text);
  background: var(--card); border: 1px solid var(--border);
  border-radius: 999px; padding: 7px 15px;
}

/* ═══════════ Projects ═══════════ */
.project-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 22px; }
@media (max-width: 760px) { .project-grid { grid-template-columns: 1fr; } }
.project {
  display: flex; flex-direction: column;
  background: var(--card); border: 1px solid var(--border); border-radius: 16px;
  overflow: hidden; box-shadow: var(--shadow);
  transition: transform .2s ease, box-shadow .2s ease, border-color .2s;
}
.project:hover { transform: translateY(-4px); box-shadow: var(--shadow-lg); border-color: var(--accent); }
.project-banner { height: 118px; display: flex; align-items: center; justify-content: center; font-size: 2.9rem; }
.g1 { background: linear-gradient(135deg, #2563eb, #7c3aed); }
.g2 { background: linear-gradient(135deg, #0891b2, #059669); }
.g3 { background: linear-gradient(135deg, #d97706, #dc2626); }
.g4 { background: linear-gradient(135deg, #7c3aed, #db2777); }
.g5 { background: linear-gradient(135deg, #0ea5e9, #6366f1); }
.g6 { background: linear-gradient(135deg, #475569, #94a3b8); }
.award {
  display: inline-flex; align-items: center; gap: 5px;
  font-size: .74rem; font-weight: 700; letter-spacing: .02em;
  color: #92400e; background: rgba(245, 158, 11, .18);
  padding: 4px 11px; border-radius: 999px;
}
:root[data-theme="dark"] .award { color: #fbbf24; background: rgba(245, 158, 11, .14); }
.pub-note {
  margin-top: 22px; display: flex; gap: 14px; align-items: baseline;
  background: var(--card); border: 1px solid var(--border); border-radius: 14px;
  padding: 18px 24px; box-shadow: var(--shadow);
}
.pub-note .pub-icon { font-size: 1.3rem; }
.pub-note p { color: var(--muted); font-size: .93rem; }
.pub-note strong { color: var(--text); }
.project-body { display: flex; flex-direction: column; flex: 1; padding: 22px 24px 20px; }
.project h3 { font-size: 1.12rem; margin-bottom: 8px; letter-spacing: -.01em; }
.project .desc { color: var(--muted); font-size: .94rem; margin-bottom: 16px; flex: 1; }
.tags { display: flex; flex-wrap: wrap; gap: 7px; margin-bottom: 16px; }
.tag {
  font-size: .74rem; font-weight: 600; letter-spacing: .02em;
  color: var(--accent-strong); background: var(--accent-soft);
  padding: 4px 11px; border-radius: 999px;
}
.project-links { display: flex; gap: 16px; border-top: 1px solid var(--border); padding-top: 14px; }
.project-links a { display: inline-flex; align-items: center; gap: 6px; font-size: .86rem; font-weight: 600; }
.project-links svg { width: 15px; height: 15px; }

/* ═══════════ Skills ═══════════ */
.skills-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 22px; }
@media (max-width: 860px) { .skills-grid { grid-template-columns: 1fr; } }
.skill-card {
  background: var(--card); border: 1px solid var(--border); border-radius: 16px;
  padding: 26px 26px 24px; box-shadow: var(--shadow);
}
.skill-card .skill-icon {
  width: 46px; height: 46px; border-radius: 12px;
  background: var(--accent-soft); color: var(--accent);
  display: flex; align-items: center; justify-content: center;
  font-size: 1.4rem; margin-bottom: 16px;
}
.skill-card h3 { font-size: 1.05rem; margin-bottom: 14px; }
.chips { display: flex; flex-wrap: wrap; gap: 8px; }
.chip {
  font-size: .84rem; font-weight: 500; color: var(--text);
  background: var(--bg-soft); border: 1px solid var(--border);
  padding: 5px 13px; border-radius: 999px;
}
.section-alt .chip { background: var(--bg); }

/* ═══════════ Experience / Education 时间线 ═══════════ */
.timeline { position: relative; margin-left: 7px; padding-left: 34px; border-left: 2px solid var(--border); }
.t-item { position: relative; padding-bottom: 44px; }
.t-item:last-child { padding-bottom: 6px; }
.t-item::before {
  content: ""; position: absolute; left: -42px; top: 7px;
  width: 12px; height: 12px; border-radius: 50%;
  background: var(--accent); box-shadow: 0 0 0 4px var(--accent-soft);
}
.t-date {
  font-size: .8rem; font-weight: 700; letter-spacing: .08em; text-transform: uppercase;
  color: var(--accent); margin-bottom: 5px;
}
.t-item h3 { font-size: 1.12rem; letter-spacing: -.01em; }
.t-org { color: var(--muted); font-weight: 500; font-size: .95rem; margin-bottom: 10px; }
.t-item ul { list-style: none; }
.t-item li {
  position: relative; padding-left: 22px;
  color: var(--muted); font-size: .95rem; margin-bottom: 7px;
}
.t-item li::before { content: "▹"; position: absolute; left: 0; color: var(--accent); }
.t-item li strong { color: var(--text); }
.t-note { color: var(--muted); font-size: .95rem; }

/* ═══════════ CV ═══════════ */
.cv-box {
  text-align: center; max-width: 620px; margin: 0 auto;
  background: var(--card); border: 1px solid var(--border); border-radius: 20px;
  padding: 52px 36px; box-shadow: var(--shadow);
}
.cv-box .cv-emoji { font-size: 2.6rem; margin-bottom: 14px; }
.cv-box h2 { font-size: 1.6rem; margin-bottom: 10px; letter-spacing: -.01em; }
.cv-box p { color: var(--muted); margin-bottom: 28px; }
.cv-actions { display: flex; gap: 14px; justify-content: center; flex-wrap: wrap; }

/* ═══════════ Footer / Contact ═══════════ */
footer { background: var(--bg-soft); border-top: 1px solid var(--border); padding: 64px 0 40px; text-align: center; }
footer .kicker {
  display: inline-block; font-size: .78rem; font-weight: 700;
  letter-spacing: .14em; text-transform: uppercase; color: var(--accent); margin-bottom: 8px;
}
footer h2 { font-size: 1.7rem; margin-bottom: 12px; letter-spacing: -.01em; }
footer .contact-note { color: var(--muted); max-width: 460px; margin: 0 auto 26px; }
footer .email-link { font-size: 1.08rem; font-weight: 600; }
footer .social-row { justify-content: center; margin: 30px 0 44px; }
.copyright { color: var(--muted); font-size: .85rem; border-top: 1px solid var(--border); padding-top: 28px; }
.copyright a { color: var(--muted); }
.copyright a:hover { color: var(--accent); }

/* ═══════════ 进场动画（滚动到视口时淡入；仅在 JS 可用时启用）═══════════ */
html.js .reveal { opacity: 0; transform: translateY(20px); transition: opacity .6s ease, transform .6s ease; }
html.js .reveal.in { opacity: 1; transform: none; }
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  html.js .reveal { opacity: 1; transform: none; transition: none; }
  .btn, .project, .social-row a, .quick-card { transition: none; }
}