/* ============================================================
   项目子页 · 统一模板
   共用 /assets/style.css 的 :root 变量
   ============================================================ */

html, body { background: var(--paper); color: var(--ink); }

/* ===== topbar ===== */
.proj-topbar {
  position: sticky; top: 0; z-index: 50;
  display: flex; align-items: center; justify-content: space-between;
  padding: 18px 32px;
  background: rgba(245,243,237,0.85);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--line-2);
}
.proj-back {
  font-family: var(--f-serif-en);
  font-style: italic;
  font-weight: 500;
  font-size: 18px;
  color: var(--ink);
  display: inline-flex; align-items: center; gap: 6px;
}
.proj-back .arrow { transition: transform 0.2s; }
.proj-back:hover .arrow { transform: translateX(-3px); }
.proj-nav { display: flex; gap: 24px; }
.proj-nav a {
  font-size: 13px;
  color: var(--ink-2);
  padding: 6px 0;
  position: relative;
  transition: color 0.2s;
}
.proj-nav a::after {
  content: '';
  position: absolute; left: 0; right: 0; bottom: 0;
  height: 1px;
  background: var(--ink);
  transform: scaleX(0); transform-origin: 0 50%;
  transition: transform 0.3s cubic-bezier(.2,.8,.2,1);
}
.proj-nav a:hover { color: var(--ink); }
.proj-nav a:hover::after { transform: scaleX(1); }

/* ===== container ===== */
.proj-container {
  width: 100%;
  max-width: 960px;
  margin: 0 auto;
  padding: 0 32px;
}

/* ===== hero ===== */
.proj-hero {
  padding: 80px 0 50px;
  border-bottom: 1px solid var(--line-2);
}
.proj-eyebrow {
  display: inline-flex; align-items: center; gap: 10px;
  font-family: var(--f-mono);
  font-size: 11px;
  color: var(--ink-3);
  letter-spacing: 0.16em;
  text-transform: uppercase;
  margin-bottom: 24px;
}
.eyebrow-dot {
  width: 7px; height: 7px;
  background: var(--accent);
  border-radius: 50%;
}
.proj-title {
  font-family: var(--f-serif-cn);
  font-weight: 500;
  font-size: clamp(48px, 7vw, 88px);
  line-height: 1.05;
  letter-spacing: -0.02em;
  margin-bottom: 20px;
  color: var(--ink);
}
.proj-en {
  font-family: var(--f-serif-en);
  font-style: italic;
  font-weight: 400;
  color: var(--ink-3);
  margin-left: 12px;
}
.proj-tag {
  font-family: var(--f-mono);
  font-size: 12px;
  color: var(--ink-3);
  letter-spacing: 0.04em;
  margin-bottom: 28px;
}
.proj-lead {
  font-family: var(--f-serif-cn);
  font-weight: 400;
  font-size: clamp(20px, 2.4vw, 28px);
  line-height: 1.4;
  color: var(--ink);
  letter-spacing: -0.005em;
  max-width: 720px;
  margin-bottom: 40px;
}
.proj-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 28px 40px;
  font-size: 13px;
  color: var(--ink-2);
  font-family: var(--f-sans);
}
.proj-meta strong {
  display: inline-block;
  font-family: var(--f-mono);
  font-size: 10px;
  color: var(--ink-3);
  text-transform: uppercase;
  letter-spacing: 0.12em;
  margin-right: 6px;
}

/* ===== cover image ===== */
.proj-cover {
  padding: 0;
  margin: 0;
  background: #0a0a0a;
}
.proj-cover img {
  display: block;
  width: 100%;
  aspect-ratio: 16 / 9;
  object-fit: cover;
}

/* ===== section ===== */
.proj-section {
  padding: 90px 0 30px;
  border-bottom: 1px solid var(--line-2);
}
.proj-section:last-of-type { border-bottom: 0; }
.proj-num {
  font-family: var(--f-mono);
  font-size: 11px;
  color: var(--ink-3);
  letter-spacing: 0.16em;
  margin-bottom: 16px;
}
.proj-section h2 {
  font-family: var(--f-serif-cn);
  font-weight: 500;
  font-size: clamp(32px, 4.5vw, 52px);
  line-height: 1.1;
  letter-spacing: -0.01em;
  color: var(--ink);
  margin-bottom: 40px;
}
.proj-prose p {
  font-size: 16px;
  line-height: 1.75;
  color: var(--ink-2);
  margin-bottom: 18px;
  max-width: 680px;
}
.proj-prose p strong { color: var(--ink); font-weight: 500; }
.proj-prose p em { color: var(--accent); font-style: normal; }

.proj-callout {
  margin: 32px 0;
  padding: 22px 26px;
  border-left: 3px solid var(--accent);
  background: rgba(194, 65, 12, 0.04);
  font-size: 15px;
  line-height: 1.7;
  color: var(--ink);
  border-radius: 0 8px 8px 0;
  max-width: 720px;
}
.proj-callout strong { font-weight: 600; }

/* ===== feature grid ===== */
.proj-feat-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
  margin-top: 8px;
}
.proj-feat {
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: 26px 24px;
  background: #fff;
  transition: border-color 0.3s, transform 0.3s;
}
.proj-feat:hover {
  border-color: var(--ink-3);
  transform: translateY(-3px);
}
.proj-feat h3 {
  font-family: var(--f-serif-cn);
  font-weight: 500;
  font-size: 19px;
  margin-bottom: 10px;
  color: var(--ink);
  letter-spacing: 0;
}
.proj-feat p {
  font-size: 14px;
  line-height: 1.65;
  color: var(--ink-2);
}

/* ===== table ===== */
.proj-table {
  width: 100%;
  border-collapse: collapse;
  margin-top: 8px;
  font-size: 14px;
}
.proj-table th,
.proj-table td {
  text-align: left;
  padding: 14px 16px;
  border-bottom: 1px solid var(--line);
}
.proj-table th {
  font-family: var(--f-mono);
  font-size: 10px;
  color: var(--ink-3);
  text-transform: uppercase;
  letter-spacing: 0.12em;
  font-weight: 500;
  background: rgba(10, 10, 10, 0.02);
}
.proj-table td:first-child {
  font-weight: 500;
  color: var(--ink);
  width: 28%;
}
.proj-table td:nth-child(2) {
  font-family: var(--f-mono);
  font-size: 12px;
  color: var(--accent);
  width: 28%;
}
.proj-table tr:last-child td { border-bottom: 0; }

/* ===== metric row ===== */
.proj-metric-row {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
  margin: 8px 0 32px;
}
.proj-metric {
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 22px 18px;
  background: #fff;
}
.proj-metric-val {
  font-family: var(--f-serif-en);
  font-weight: 500;
  font-size: 32px;
  color: var(--ink);
  line-height: 1;
  margin-bottom: 8px;
}
.proj-metric-val .unit { font-size: 14px; color: var(--ink-3); margin-left: 2px; }
.proj-metric-lbl {
  font-size: 12px;
  color: var(--ink-3);
  font-family: var(--f-mono);
  letter-spacing: 0.04em;
}

/* ===== list (项目难点/设计) ===== */
.proj-list {
  margin: 0;
  padding: 0;
  list-style: none;
  max-width: 720px;
}
.proj-list li {
  position: relative;
  padding: 14px 0 14px 28px;
  font-size: 15px;
  line-height: 1.7;
  color: var(--ink-2);
  border-bottom: 1px solid var(--line-2);
}
.proj-list li:last-child { border-bottom: 0; }
.proj-list li::before {
  content: '—';
  position: absolute;
  left: 0; top: 14px;
  color: var(--accent);
  font-weight: 500;
}
.proj-list li strong { color: var(--ink); font-weight: 500; }

/* ===== cta row ===== */
.proj-cta {
  padding: 80px 0 100px;
  display: flex;
  gap: 16px;
  justify-content: center;
  flex-wrap: wrap;
}
.proj-cta .cta-btn {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 14px 26px;
  border-radius: 999px;
  font-size: 14px;
  font-weight: 500;
  transition: all 0.2s;
}
.proj-cta .cta-primary { background: var(--ink); color: var(--paper); }
.proj-cta .cta-primary:hover { background: #222; transform: translateY(-2px); }
.proj-cta .cta-ghost { background: transparent; color: var(--ink); border: 1px solid var(--ink); }
.proj-cta .cta-ghost:hover { background: var(--ink); color: var(--paper); }

/* ===== floating download (redline only) ===== */
.proj-floating-dl {
  position: fixed;
  z-index: 30;
  right: 24px;
  top: 50%;
  transform: translateY(-50%);
  width: 220px;
  padding: 22px 20px;
  background: rgba(255, 255, 255, 0.96);
  border: 1px solid var(--line);
  border-radius: 18px;
  box-shadow: 0 18px 50px rgba(10, 10, 10, 0.12);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
}
.proj-floating-dl .dl-tag {
  display: inline-block;
  font-family: var(--f-mono);
  font-size: 10px;
  color: var(--accent);
  letter-spacing: 0.1em;
  text-transform: uppercase;
  margin-bottom: 8px;
  font-weight: 500;
}
.proj-floating-dl h3 {
  font-family: var(--f-serif-cn);
  font-weight: 500;
  font-size: 19px;
  margin-bottom: 8px;
  color: var(--ink);
}
.proj-floating-dl p {
  font-size: 12px;
  line-height: 1.55;
  color: var(--ink-2);
  margin-bottom: 14px;
}
.proj-floating-dl .dl-btn {
  display: block;
  width: 100%;
  padding: 9px 12px;
  text-align: center;
  border-radius: 999px;
  font-size: 13px;
  font-weight: 500;
  margin-bottom: 8px;
  background: var(--ink);
  color: var(--paper);
  transition: background 0.2s;
}
.proj-floating-dl .dl-btn:hover { background: #222; }
.proj-floating-dl .dl-btn.secondary {
  background: transparent;
  color: var(--ink);
  border: 1px solid var(--ink);
}
.proj-floating-dl .dl-btn.secondary:hover { background: var(--ink); color: var(--paper); }
.proj-floating-dl .dl-req {
  display: block;
  font-family: var(--f-mono);
  font-size: 10px;
  color: var(--ink-3);
  text-align: center;
  margin-top: 6px;
  letter-spacing: 0.05em;
}

/* ===== responsive ===== */
@media (max-width: 900px) {
  .proj-floating-dl {
    position: static;
    transform: none;
    width: auto;
    max-width: 540px;
    margin: 32px auto 0;
  }
  .proj-feat-grid { grid-template-columns: 1fr; }
  .proj-metric-row { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 600px) {
  .proj-meta { gap: 18px 24px; font-size: 12px; }
  .proj-metric-row { grid-template-columns: repeat(2, 1fr); gap: 12px; }
  .proj-table { font-size: 13px; }
  .proj-table th, .proj-table td { padding: 10px 8px; }
}

/* ===== fade-in animation ===== */
@keyframes fadeUp { from { opacity: 0; transform: translateY(20px); } to { opacity: 1; transform: translateY(0); } }
.proj-section, .proj-cover, .proj-hero { animation: fadeUp 0.7s cubic-bezier(.2,.8,.2,1) both; }
.proj-hero { animation-delay: 0.05s; }
.proj-cover { animation-delay: 0.1s; }