:root {
  --bg: #FAF9F4;
  --ink: #0F1E19;
  --ink-soft: #3D4F48;
  --ink-mute: #6B7C75;
  --ink-line: #E5E2D8;
  --bitan-50: #E8F3EE;
  --bitan-100: #C5E0D4;
  --bitan-200: #9FCCB8;
  --bitan-300: #6BAF92;
  --bitan-400: #3D9170;
  --bitan-500: #1F5E4B;
  --bitan-600: #184A3B;
  --radius: 16px;
  --shadow: 0 24px 60px -32px rgba(15,30,25,0.22);
}

* { box-sizing: border-box; margin: 0; padding: 0; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", sans-serif;
  background: var(--bg);
  color: var(--ink);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }

.container { max-width: 1152px; margin: 0 auto; padding: 0 20px; }

/* Header */
.site-header {
  position: sticky; top: 0; z-index: 40;
  background: rgba(250,249,244,0.85);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--ink-line);
  box-shadow: 0 8px 30px -20px rgba(15,30,25,0.18);
}
.header-inner {
  display: flex; align-items: center; justify-content: space-between;
  height: 64px;
}
.brand { display: flex; align-items: center; gap: 10px; font-weight: 600; font-size: 15px; }
.brand img { width: 32px; height: 32px; border-radius: 8px; box-shadow: 0 1px 3px rgba(0,0,0,0.08); }
.nav { display: flex; gap: 4px; font-size: 14px; color: var(--ink-soft); }
.nav a { padding: 6px 12px; border-radius: 999px; transition: color .2s; }
.nav a:hover, .nav a.active { color: var(--bitan-500); }
.btn-primary {
  display: inline-flex; align-items: center; gap: 6px;
  background: var(--bitan-500); color: #fff;
  padding: 8px 16px; border-radius: 999px;
  font-size: 13px; font-weight: 500;
  box-shadow: 0 8px 20px -10px rgba(31,94,75,0.5);
  transition: transform .2s, background .2s;
  border: none; cursor: pointer;
}
.btn-primary:hover { background: var(--bitan-600); transform: translateY(-1px); }
.btn-outline {
  display: inline-flex; align-items: center; gap: 6px;
  border: 1px solid var(--ink-line); background: rgba(255,255,255,0.7);
  padding: 10px 24px; border-radius: 999px;
  font-size: 14px; color: var(--ink-soft);
  transition: border-color .2s, color .2s;
}
.btn-outline:hover { border-color: var(--bitan-300); color: var(--bitan-500); }

/* Hero */
.hero { padding: 80px 0 100px; border-bottom: 1px solid var(--ink-line); position: relative; overflow: hidden; }
.hero-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 56px; align-items: center; }
@media (max-width: 768px) { .hero-grid { grid-template-columns: 1fr; } .nav { display: none; } }
.badge {
  display: inline-flex; align-items: center; gap: 8px;
  border: 1px solid var(--ink-line); background: rgba(255,255,255,0.6);
  padding: 6px 12px; border-radius: 999px;
  font-size: 11px; color: var(--bitan-500); margin-bottom: 24px;
}
.badge::before { content: ''; width: 6px; height: 6px; border-radius: 50%; background: var(--bitan-400); }
.hero h1 { font-size: clamp(36px, 5vw, 56px); line-height: 1.1; font-weight: 600; }
.hero h1 em { font-style: italic; color: var(--bitan-500); }
.hero h1 .suffix { font-size: 0.5em; color: var(--ink-soft); font-style: normal; font-weight: 400; }
.hero-desc { margin-top: 24px; color: var(--ink-mute); font-size: 15px; max-width: 480px; }
.hero-actions { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 36px; }
.hero-stats { display: grid; grid-template-columns: repeat(3,1fr); gap: 24px; margin-top: 40px; padding-top: 24px; border-top: 1px solid var(--ink-line); }
.hero-stats dt { font-size: 11px; text-transform: uppercase; letter-spacing: 0.08em; color: var(--bitan-500); }
.hero-stats dd { font-size: 14px; font-weight: 500; margin-top: 4px; }

/* Install section */
.section { padding: 80px 0; }
.section-title { text-align: center; margin-bottom: 48px; }
.section-title .kicker { font-size: 11px; text-transform: uppercase; letter-spacing: 0.12em; color: var(--bitan-500); }
.section-title h2 { font-size: 32px; margin-top: 8px; }
.tabs { display: flex; justify-content: center; gap: 8px; margin-bottom: 32px; }
.tab-btn {
  padding: 10px 20px; border-radius: 999px; border: 1px solid var(--ink-line);
  background: #fff; font-size: 14px; cursor: pointer; color: var(--ink-soft);
}
.tab-btn.active { background: var(--bitan-500); color: #fff; border-color: var(--bitan-500); }
.panel { display: none; }
.panel.active { display: block; }
.card {
  background: #fff; border: 1px solid var(--ink-line);
  border-radius: 24px; box-shadow: var(--shadow); overflow: hidden;
  max-width: 640px; margin: 0 auto;
}
.card-body { padding: 28px 32px; }
.form-group { margin-bottom: 20px; }
.form-group label { display: block; font-size: 14px; font-weight: 600; margin-bottom: 8px; }
.form-group .hint { font-size: 12px; color: var(--ink-mute); margin-top: 4px; }
.form-input {
  width: 100%; padding: 12px 16px; border: 1px solid var(--ink-line);
  border-radius: var(--radius); background: var(--bg); font-size: 14px;
  transition: border-color .2s, background .2s;
}
.form-input:focus { outline: none; border-color: var(--bitan-400); background: #fff; }
.file-slot {
  display: flex; align-items: flex-start; gap: 16px;
  padding: 20px; border: 2px dashed var(--ink-line); border-radius: var(--radius);
  cursor: pointer; transition: border-color .2s, background .2s;
}
.file-slot:hover { border-color: var(--bitan-300); background: #fff; }
.file-slot.has-file { border-color: var(--bitan-400); background: #fff; }
.file-icon {
  width: 44px; height: 44px; border-radius: 12px;
  background: var(--bitan-50); color: var(--bitan-500);
  display: flex; align-items: center; justify-content: center; flex-shrink: 0;
}
.card-footer {
  padding: 16px 32px; border-top: 1px solid var(--ink-line);
  background: var(--bg); display: flex; justify-content: space-between; align-items: center; flex-wrap: wrap; gap: 12px;
}
.card-footer .note { font-size: 12px; color: var(--ink-mute); }

/* Features */
.features-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(280px, 1fr)); gap: 16px; }
.feature-card {
  padding: 24px; border: 1px solid var(--ink-line); border-radius: var(--radius);
  background: #fff; transition: transform .2s, box-shadow .2s;
}
.feature-card:hover { transform: translateY(-2px); box-shadow: var(--shadow); }
.feature-card h3 { font-size: 16px; margin-bottom: 8px; }
.feature-card p { font-size: 13px; color: var(--ink-mute); }

/* Footer */
.site-footer { border-top: 1px solid var(--ink-line); padding: 48px 0 32px; background: #fff; }
.footer-grid { display: grid; grid-template-columns: 2fr 1fr 1fr; gap: 40px; }
@media (max-width: 768px) { .footer-grid { grid-template-columns: 1fr; } }
.footer-grid h4 { font-size: 14px; margin-bottom: 12px; }
.footer-grid ul { list-style: none; }
.footer-grid li { margin-bottom: 8px; font-size: 13px; color: var(--ink-mute); }
.footer-bottom { margin-top: 32px; padding-top: 24px; border-top: 1px solid var(--ink-line); font-size: 12px; color: var(--ink-mute); display: flex; justify-content: space-between; flex-wrap: wrap; gap: 8px; }

.alert { padding: 12px 16px; border-radius: var(--radius); font-size: 13px; margin-top: 12px; display: none; }
.alert.error { background: #FEF2F2; border: 1px solid #FECACA; color: #B91C1C; display: block; }
.alert.success { background: #ECFDF5; border: 1px solid #A7F3D0; color: #047857; display: block; }

/* Docs */
.docs { padding: 60px 0; }
.doc-section { margin-bottom: 40px; }
.doc-section h3 { font-size: 18px; margin-bottom: 12px; color: var(--bitan-500); }
.doc-table { width: 100%; border-collapse: collapse; font-size: 13px; margin: 12px 0; }
.doc-table th, .doc-table td { border: 1px solid var(--ink-line); padding: 10px 14px; text-align: left; }
.doc-table th { background: var(--bitan-50); }
.code-block { margin: 12px 0; }
.code-block textarea.code {
  width: 100%; min-height: 120px; padding: 14px;
  background: #1a1a2e; color: #e0e0e0; border: none; border-radius: 12px;
  font-family: "SF Mono", Monaco, Consolas, monospace; font-size: 12px; resize: vertical;
}
.tag { display: inline-block; padding: 2px 8px; border-radius: 4px; font-size: 11px; font-weight: 600; }
.tag.post { background: #DBEAFE; color: #1D4ED8; }
.tag.get { background: #D1FAE5; color: #047857; }