/* ============================================================
   四时工坊 · 项目详情页共享底座（proj-base）
   只负责：纸底画布 / 顶栏 / 菜单 / 页脚 / 滚动显现。
   每个项目的个性全部由各自页面的 <style> 独立发挥。
   ============================================================ */
:root {
  --paper: #FAF6EC;
  --card: #FFFFFF;
  --ink: #1A1A1A;
  --ink-2: #57534A;
  --ink-3: #9C968A;
  --line: rgba(26, 26, 26, 0.12);
  --hair: rgba(26, 26, 26, 0.08);
  --gold: #F5C445;
  --ac: var(--ink);            /* 每页覆盖为自己的项目主题色 */
  --font-sans: "Helvetica Neue", -apple-system, "PingFang SC", "Noto Sans SC", "Microsoft YaHei", sans-serif;
  --font-mono: "Sarasa Mono SC", "SF Mono", "JetBrains Mono", Consolas, monospace;
  --shadow: 0 1px 2px rgba(26,26,26,.04), 0 16px 40px rgba(26,26,26,.07);
  --shadow-lg: 0 2px 4px rgba(26,26,26,.05), 0 26px 60px rgba(26,26,26,.12);
}
* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--font-sans);
  color: var(--ink);
  background-color: var(--paper);
  background-image:
    radial-gradient(1100px 700px at 88% -8%, rgba(245,196,69,0.12), transparent 62%),
    radial-gradient(900px 640px at -12% 34%, rgba(245,196,69,0.07), transparent 58%),
    linear-gradient(var(--hair) 1px, transparent 1px),
    linear-gradient(90deg, var(--hair) 1px, transparent 1px);
  background-size: auto, auto, 48px 48px, 48px 48px;
  -webkit-font-smoothing: antialiased;
  overflow-x: clip;
}
::selection { background: rgba(245,196,69,.55); }
a { color: inherit; }
.wrap { max-width: 1160px; margin: 0 auto; padding: 0 clamp(20px, 4vw, 48px); }

/* ---------- 顶栏 ---------- */
.topbar {
  position: fixed; top: 0; left: 0; right: 0; z-index: 60;
  height: 60px;
  display: flex; align-items: center; justify-content: space-between;
  padding: 0 clamp(20px, 4vw, 48px);
  background: rgba(250, 246, 236, 0.86);
  backdrop-filter: blur(10px); -webkit-backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--hair);
}
.brand {
  display: inline-flex; align-items: center; gap: 10px;
  text-decoration: none; font-weight: 800; font-size: 16px; letter-spacing: -0.01em;
}
.brand .dot {
  width: 10px; height: 10px; border-radius: 50%;
  background: var(--gold); border: 2px solid var(--ink);
}
.top-links { display: flex; align-items: center; gap: clamp(16px, 2.4vw, 28px); }
.top-links a {
  font-size: 14px; color: var(--ink-2); text-decoration: none;
  transition: color .15s;
}
.top-links a:hover { color: var(--ink); }
.top-links a.gh {
  background: var(--ink); color: var(--paper);
  padding: 7px 16px; border-radius: 999px; font-weight: 600;
}
.top-links a.gh:hover { opacity: .85; }
.menu-btn {
  display: none; width: 40px; height: 40px; border: none; background: transparent;
  flex-direction: column; justify-content: center; align-items: center; gap: 5px; cursor: pointer;
}
.menu-btn span { width: 20px; height: 2px; background: var(--ink); border-radius: 1px; transition: transform .3s, opacity .3s; }
.menu-btn.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.menu-btn.open span:nth-child(2) { opacity: 0; }
.menu-btn.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }
.menu-overlay {
  position: fixed; inset: 0; z-index: 55;
  background: var(--paper);
  display: flex; flex-direction: column; align-items: center; justify-content: center; gap: 4px;
  opacity: 0; pointer-events: none; transition: opacity .3s;
}
.menu-overlay.open { opacity: 1; pointer-events: auto; }
.menu-overlay a {
  font-size: 19px; font-weight: 600; color: var(--ink); text-decoration: none;
  padding: 13px 0; width: min(320px, 80vw); text-align: center;
  border-bottom: 1px solid var(--hair);
}
.menu-overlay a.gh { border: none; background: var(--ink); color: var(--paper); border-radius: 999px; padding: 13px 34px; margin-top: 20px; }

/* ---------- 区块 ---------- */
main { display: block; }
.wrap-section { padding: clamp(64px, 9vw, 110px) 0; border-top: 1px solid var(--hair); }
.kicker {
  display: flex; align-items: center; gap: 10px;
  font-family: var(--font-mono); font-size: 11.5px;
  color: var(--ink-2); letter-spacing: 0.22em;
}
.kicker::before { content: ""; width: 26px; height: 2px; background: var(--ink); }

/* ---------- 页脚 ---------- */
footer { border-top: 1px solid var(--hair); padding: 42px 0 40px; }
.footer-inner {
  display: flex; justify-content: space-between; flex-wrap: wrap; gap: 14px;
  font-family: var(--font-mono); font-size: 12px; color: var(--ink-3);
}

/* ---------- 滚动显现 ---------- */
.reveal {
  opacity: 0; transform: translateY(26px);
  transition: opacity .8s ease, transform .8s cubic-bezier(.22,1,.36,1);
  transition-delay: var(--d, 0s);
}
.reveal.in { opacity: 1; transform: none; }

@media (max-width: 820px) {
  .top-links { display: none; }
  .menu-btn { display: flex; }
  .wrap { padding: 0 20px; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .reveal { opacity: 1; transform: none; transition: none; }
}