/* ============================================================
   Kalev Yang 个人展示站 — 主样式
   结构：reset → 工具类 → 导航 → Hero → 板块头 → 技术栈
        → 项目（精选/更多）→ 文章 → 数据 → 关于 → 页脚
        → 响应式 → reduced-motion
   ============================================================ */

/* ---------- Reset ---------- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html { scroll-behavior: smooth; }

body {
  font-family: var(--font-body);
  background: var(--paper);
  color: var(--ink-1);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

img { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
ul { list-style: none; }
button { font: inherit; background: none; border: none; cursor: pointer; color: inherit; }

::selection { background: var(--accent); color: #fff; }

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

/* ---------- 工具类 ---------- */
.container { max-width: var(--container); margin: 0 auto; padding: 0 24px; }
.mono { font-family: var(--font-mono); }
.accent { color: var(--accent); }
.text-link { color: var(--ink-1); border-bottom: 1px solid var(--line-strong); transition: color 0.25s, border-color 0.25s; }
.text-link:hover { color: var(--accent); border-color: var(--accent); }

.skip-link {
  position: absolute; left: -9999px; top: 8px; z-index: 200;
  background: var(--ink-1); color: var(--paper); padding: 8px 16px; border-radius: 8px;
}
.skip-link:focus { left: 8px; }

/* 滚动揭示（JS 加 .in；--i 控制 stagger） */
.reveal {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity var(--dur) var(--ease-out), transform var(--dur) var(--ease-out);
  transition-delay: calc(var(--i, 0) * 60ms);
}
.reveal.in { opacity: 1; transform: none; }

/* 板块锚点偏移（避开 fixed 导航） */
section { scroll-margin-top: calc(var(--nav-h) + 16px); }

/* ========== 导航 ========== */
.nav {
  position: fixed; inset: 0 0 auto 0; z-index: 100;
  background: rgba(251, 251, 249, 0.75);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid transparent;
  transition: border-color 0.3s, background 0.3s;
}
@supports not (backdrop-filter: blur(1px)) {
  .nav { background: var(--paper); }
}
.nav.scrolled { border-bottom-color: var(--line); }

.nav-inner { height: var(--nav-h); display: flex; align-items: center; gap: 32px; }

.brand {
  font-family: var(--font-display);
  font-weight: 600; font-size: 1.25rem; letter-spacing: -0.01em;
}

.nav-links { display: flex; gap: 28px; margin-left: auto; }
.nav-links a {
  position: relative; font-size: 0.9rem; color: var(--ink-2);
  padding: 4px 0; transition: color 0.25s;
}
.nav-links a::after {
  content: ""; position: absolute; left: 0; bottom: 0;
  width: 100%; height: 1px; background: var(--accent);
  transform: scaleX(0); transform-origin: left;
  transition: transform 0.3s var(--ease-out);
}
.nav-links a:hover, .nav-links a.active { color: var(--ink-1); }
.nav-links a:hover::after, .nav-links a.active::after { transform: scaleX(1); }

.nav-right { display: flex; align-items: center; gap: 16px; }
.nav-github {
  font-size: 0.8rem; color: var(--ink-1);
  border: 1px solid var(--line-strong); border-radius: 999px;
  padding: 6px 14px; transition: border-color 0.25s, color 0.25s;
}
.nav-github:hover { border-color: var(--accent); color: var(--accent); }

.nav-toggle { display: none; flex-direction: column; gap: 5px; padding: 8px; }
.nav-toggle span { width: 20px; height: 1.5px; background: var(--ink-1); transition: transform 0.3s; }

/* ========== Hero ========== */
.hero {
  position: relative; overflow: hidden;
  min-height: 96vh;
  display: flex; flex-direction: column; justify-content: center;
  padding: calc(var(--nav-h) + 48px) 0 96px;
}

/* 细网格背景 + 顶部暖色晕染，缓慢漂移 */
.hero-bg {
  position: absolute; inset: 0; pointer-events: none;
  background-image:
    radial-gradient(600px 400px at 85% 10%, var(--accent-soft), transparent 70%),
    linear-gradient(var(--line) 1px, transparent 1px),
    linear-gradient(90deg, var(--line) 1px, transparent 1px);
  background-size: 100% 100%, 56px 56px, 56px 56px;
  -webkit-mask-image: linear-gradient(to bottom, black 55%, transparent 96%);
  mask-image: linear-gradient(to bottom, black 55%, transparent 96%);
  animation: gridDrift 24s ease-in-out infinite alternate;
}
@keyframes gridDrift {
  from { background-position: 0 0, 0 0, 0 0; }
  to   { background-position: 0 0, 28px 28px, 28px 28px; }
}

.hero-inner { position: relative; }

.hero-kicker { font-size: 0.85rem; color: var(--ink-3); margin-bottom: 20px; }

.hero-title {
  font-family: var(--font-display);
  font-size: clamp(3.25rem, 9.5vw, 6.75rem);
  font-weight: 600; letter-spacing: -0.03em; line-height: 1.02;
}
.hero-title em { font-style: italic; font-weight: 500; }

.hero-tagline {
  margin-top: 24px;
  font-size: clamp(1.05rem, 2.2vw, 1.35rem);
  color: var(--ink-2); max-width: 560px;
}

.hero-typer {
  margin-top: 28px; font-size: 0.95rem; color: var(--ink-1);
  min-height: 1.6em;
}
.typer-prefix { color: var(--accent); font-weight: 600; }
.caret {
  display: inline-block; width: 9px; height: 1.1em;
  background: var(--accent); vertical-align: text-bottom; margin-left: 3px;
  animation: blink 1s steps(1) infinite;
}
@keyframes blink { 50% { opacity: 0; } }

.hero-cta { display: flex; gap: 14px; margin-top: 36px; flex-wrap: wrap; }

.btn {
  display: inline-flex; align-items: center;
  padding: 13px 26px; border-radius: var(--radius-sm);
  font-size: 0.95rem; font-weight: 500;
  transition: transform 0.25s var(--ease-out), background 0.25s, color 0.25s, border-color 0.25s, box-shadow 0.25s;
}
.btn:active { transform: translateY(1px); }
.btn-primary { background: var(--ink-1); color: var(--paper); }
.btn-primary:hover { background: var(--accent); color: #fff; box-shadow: var(--shadow-lift); transform: translateY(-2px); }
.btn-ghost { border: 1px solid var(--line-strong); color: var(--ink-1); }
.btn-ghost:hover { border-color: var(--ink-1); transform: translateY(-2px); }

.hero-meta { margin-top: 48px; font-size: 0.78rem; color: var(--ink-3); letter-spacing: 0.02em; }

.scroll-hint {
  position: absolute; bottom: 28px; left: 50%; transform: translateX(-50%);
  font-size: 0.7rem; letter-spacing: 0.2em; color: var(--ink-3);
  animation: hintFloat 2.4s ease-in-out infinite;
}
@keyframes hintFloat { 50% { transform: translate(-50%, 6px); } }

/* ========== 板块通用 ========== */
.section { padding: 112px 0; }
.section-alt { background: var(--paper-2); border-block: 1px solid var(--line); }

.sec-head { margin-bottom: 56px; max-width: 640px; }
.sec-index { font-size: 0.78rem; letter-spacing: 0.18em; color: var(--ink-3); margin-bottom: 14px; }
.sec-title {
  font-family: var(--font-display);
  font-size: clamp(2rem, 5vw, 3.1rem);
  font-weight: 600; letter-spacing: -0.02em; line-height: 1.15;
}
.sec-sub { margin-top: 14px; color: var(--ink-2); }

/* ========== 01 技术栈矩阵 ========== */
.tech-grid {
  display: grid; gap: 20px;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
}

.tech-card {
  background: var(--card); border: 1px solid var(--line);
  border-radius: var(--radius); padding: 26px 26px 22px;
  box-shadow: var(--shadow-card);
  transition: transform 0.3s var(--ease-out), box-shadow 0.3s, border-color 0.3s;
}
.tech-card:hover { transform: translateY(-4px); box-shadow: var(--shadow-lift); border-color: var(--line-strong); }

.tech-card-head { display: flex; align-items: center; gap: 10px; margin-bottom: 18px; }
.tech-dot { width: 10px; height: 10px; border-radius: 50%; background: var(--group-color, var(--accent)); }
.tech-name { font-family: var(--font-display); font-size: 1.15rem; font-weight: 600; letter-spacing: -0.01em; }
.tech-count { margin-left: auto; font-size: 0.72rem; color: var(--ink-3); }

.tech-items li {
  display: flex; align-items: center; justify-content: space-between;
  padding: 9px 0; border-top: 1px solid var(--line);
  font-size: 0.92rem;
}
.tech-items li:first-child { border-top: none; }
.level { display: inline-flex; gap: 5px; }
.level i {
  width: 7px; height: 7px; border-radius: 50%;
  background: var(--line-strong);
}
.level i.on { background: var(--group-color, var(--accent)); }

/* ========== 02 精选项目 ========== */
.featured-list { display: flex; flex-direction: column; gap: 24px; }

.featured-card {
  position: relative;
  display: grid; grid-template-columns: 1fr; gap: 8px;
  background: var(--card); border: 1px solid var(--line);
  border-radius: var(--radius); padding: 36px;
  box-shadow: var(--shadow-card);
  transition: transform 0.3s var(--ease-out), box-shadow 0.3s, border-color 0.3s;
  overflow: hidden;
}
/* accent 书脊条：hover 时展开 */
.featured-card::before {
  content: ""; position: absolute; left: 0; top: 0; bottom: 0; width: 3px;
  background: var(--accent);
  transform: scaleY(0); transform-origin: top;
  transition: transform 0.35s var(--ease-out);
}
.featured-card:hover { transform: translateY(-4px); box-shadow: var(--shadow-lift); border-color: var(--line-strong); }
.featured-card:hover::before { transform: scaleY(1); }

.fc-meta { display: flex; align-items: center; gap: 14px; font-size: 0.75rem; color: var(--ink-3); letter-spacing: 0.08em; }
.fc-index { color: var(--accent); font-weight: 600; }

.fc-title {
  font-family: var(--font-display);
  font-size: clamp(1.5rem, 3vw, 2rem); font-weight: 600; letter-spacing: -0.015em;
  margin-top: 10px;
}
.fc-title a { background-image: linear-gradient(var(--accent), var(--accent)); background-size: 0% 2px; background-repeat: no-repeat; background-position: 0 100%; transition: background-size 0.35s var(--ease-out); }
.featured-card:hover .fc-title a { background-size: 100% 2px; }

.fc-desc { color: var(--ink-2); margin-top: 10px; max-width: 640px; }

.fc-highlights { margin-top: 16px; display: flex; flex-direction: column; gap: 6px; }
.fc-highlights li { font-size: 0.92rem; color: var(--ink-2); padding-left: 20px; position: relative; }
.fc-highlights li::before { content: "›"; position: absolute; left: 4px; color: var(--accent); font-weight: 600; }

.fc-foot { display: flex; align-items: center; gap: 16px; margin-top: 22px; flex-wrap: wrap; }
.tags { display: flex; gap: 8px; flex-wrap: wrap; }
.tag {
  font-family: var(--font-mono); font-size: 0.72rem; color: var(--ink-2);
  background: var(--paper-2); border: 1px solid var(--line);
  padding: 4px 10px; border-radius: 999px;
}
.fc-link {
  margin-left: auto; font-family: var(--font-mono); font-size: 0.8rem;
  color: var(--ink-1); display: inline-flex; gap: 6px; align-items: center;
  transition: color 0.25s;
}
.fc-link:hover { color: var(--accent); }
.fc-link .arrow { transition: transform 0.25s var(--ease-out); }
.fc-link:hover .arrow { transform: translate(3px, -3px); }

/* ========== 02b 更多项目 ========== */
.more-head {
  display: flex; align-items: flex-end; justify-content: space-between;
  gap: 20px; flex-wrap: wrap;
  margin: 88px 0 28px;
}
.more-title { font-family: var(--font-display); font-size: 1.6rem; font-weight: 600; letter-spacing: -0.015em; }

.chips { display: flex; gap: 8px; flex-wrap: wrap; }
.chip {
  font-family: var(--font-mono); font-size: 0.75rem;
  padding: 6px 14px; border-radius: 999px;
  border: 1px solid var(--line-strong); color: var(--ink-2);
  transition: all 0.25s;
}
.chip:hover { border-color: var(--ink-1); color: var(--ink-1); }
.chip.active { background: var(--ink-1); border-color: var(--ink-1); color: var(--paper); }

.project-grid {
  display: grid; gap: 16px;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
}

.p-card {
  display: flex; flex-direction: column;
  background: var(--card); border: 1px solid var(--line);
  border-radius: var(--radius-sm); padding: 22px;
  box-shadow: var(--shadow-card);
  transition: transform 0.3s var(--ease-out), box-shadow 0.3s, border-color 0.3s;
}
.p-card:hover { transform: translateY(-4px); box-shadow: var(--shadow-lift); border-color: var(--line-strong); }

.p-head { display: flex; align-items: baseline; justify-content: space-between; gap: 10px; }
.p-name { font-weight: 600; font-size: 1.02rem; }
.p-name a:hover { color: var(--accent); }
.p-arrow { font-family: var(--font-mono); font-size: 0.8rem; color: var(--ink-3); transition: transform 0.25s var(--ease-out), color 0.25s; }
.p-card:hover .p-arrow { transform: translate(3px, -3px); color: var(--accent); }

.p-desc {
  margin-top: 8px; font-size: 0.88rem; color: var(--ink-2);
  display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical; overflow: hidden;
  flex: 1;
}

.p-foot { display: flex; align-items: center; gap: 10px; margin-top: 16px; }
.p-lang { display: inline-flex; align-items: center; gap: 6px; font-family: var(--font-mono); font-size: 0.72rem; color: var(--ink-2); }
.p-lang i { width: 9px; height: 9px; border-radius: 50%; }
.p-cat { margin-left: auto; font-family: var(--font-mono); font-size: 0.7rem; color: var(--ink-3); }

/* ========== 03 最新文章 ========== */
.post-list { border-top: 1px solid var(--line); }

.post-item {
  display: grid; grid-template-columns: 110px 1fr auto; gap: 24px; align-items: baseline;
  padding: 26px 8px;
  border-bottom: 1px solid var(--line);
  transition: background 0.25s, padding 0.25s;
}
.post-item:hover { background: var(--card); }

.post-date { font-family: var(--font-mono); font-size: 0.75rem; color: var(--ink-3); }

.post-title {
  font-family: var(--font-display);
  font-size: clamp(1.15rem, 2.4vw, 1.5rem); font-weight: 600; letter-spacing: -0.01em;
  transition: color 0.25s;
}
.post-item:hover .post-title { color: var(--accent); }

.post-excerpt { margin-top: 6px; font-size: 0.9rem; color: var(--ink-2); max-width: 640px; }

.post-tags { display: flex; gap: 8px; margin-top: 10px; flex-wrap: wrap; }
.post-cat {
  font-family: var(--font-mono); font-size: 0.7rem; color: var(--accent);
  background: var(--accent-soft); padding: 3px 10px; border-radius: 999px;
}

.post-arrow {
  font-family: var(--font-mono); font-size: 0.9rem; color: var(--ink-3);
  transition: transform 0.25s var(--ease-out), color 0.25s;
}
.post-item:hover .post-arrow { transform: translate(4px, -4px); color: var(--accent); }

/* ========== 数据速览 ========== */
.stats-band { border-block: 1px solid var(--line); background: var(--paper); padding: 72px 0; }
.stat-row { display: grid; grid-template-columns: repeat(auto-fit, minmax(160px, 1fr)); gap: 32px; text-align: center; }
.stat-num {
  font-family: var(--font-display);
  font-size: clamp(2.5rem, 6vw, 3.75rem); font-weight: 600; letter-spacing: -0.02em; line-height: 1;
}
.stat-num .suffix { color: var(--accent); }
.stat-label { margin-top: 10px; font-family: var(--font-mono); font-size: 0.75rem; letter-spacing: 0.12em; color: var(--ink-3); }

/* ========== 04 关于 / 联系 ========== */
.about-grid { display: grid; grid-template-columns: 1.5fr 1fr; gap: 64px; align-items: start; }

.about-bio { font-size: clamp(1.05rem, 2vw, 1.3rem); line-height: 1.9; color: var(--ink-1); }
.about-bio strong { color: var(--accent); font-weight: 600; }

.side-label { font-size: 0.72rem; letter-spacing: 0.18em; color: var(--ink-3); margin-bottom: 16px; }

.social-list { border-top: 1px solid var(--line); }
.social-item {
  display: flex; align-items: center; justify-content: space-between;
  padding: 16px 4px; border-bottom: 1px solid var(--line);
  font-size: 0.95rem;
  transition: padding 0.25s, background 0.25s;
}
.social-item:hover { padding-left: 12px; background: var(--card); }
.social-item .s-label { font-weight: 500; }
.social-item .s-url { font-family: var(--font-mono); font-size: 0.72rem; color: var(--ink-3); }
.social-item .s-arrow { color: var(--ink-3); transition: transform 0.25s var(--ease-out), color 0.25s; }
.social-item:hover .s-arrow { transform: translate(3px, -3px); color: var(--accent); }

/* ========== 页脚 ========== */
.footer { border-top: 1px solid var(--line); padding: 28px 0; }
.footer-inner {
  display: flex; justify-content: space-between; align-items: center; gap: 16px; flex-wrap: wrap;
  font-size: 0.72rem; color: var(--ink-3); letter-spacing: 0.04em;
}
.to-top:hover { color: var(--accent); }

/* ========== 响应式 ========== */
@media (max-width: 960px) {
  .about-grid { grid-template-columns: 1fr; gap: 40px; }
  .section { padding: 88px 0; }
}

@media (max-width: 640px) {
  .nav-links {
    position: absolute; top: var(--nav-h); left: 0; right: 0;
    flex-direction: column; gap: 0;
    background: var(--paper); border-bottom: 1px solid var(--line);
    padding: 8px 24px 16px;
    display: none;
  }
  .nav-links.open { display: flex; }
  .nav-links a { padding: 12px 0; border-top: 1px solid var(--line); font-size: 1rem; }
  .nav-links a:first-child { border-top: none; }
  .nav-toggle { display: flex; }
  .nav-toggle[aria-expanded="true"] span:first-child { transform: translateY(3.5px) rotate(45deg); }
  .nav-toggle[aria-expanded="true"] span:last-child { transform: translateY(-3px) rotate(-45deg); }

  .hero { min-height: 88vh; }
  .hero-meta { margin-top: 36px; }
  .post-item { grid-template-columns: 1fr; gap: 8px; }
  .post-arrow { display: none; }
  .featured-card { padding: 26px 22px; }
  .fc-link { margin-left: 0; }
}

/* ========== 动效降级 ========== */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: 0.001s !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001s !important;
  }
  .reveal { opacity: 1; transform: none; }
  .hero-bg, .scroll-hint { animation: none; }
}