:root {
  --color-primary: #2563eb;
  --color-primary-dark: #1d4ed8;
  --color-bg: #f7f8fa;
  --color-surface: #ffffff;
  --color-text: #1f2937;
  --color-muted: #6b7280;
  --color-border: #e5e7eb;
  --color-danger: #dc2626;
  --color-success: #16a34a;
  --radius: 8px;
  --max-width: 1080px;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: -apple-system, "Segoe UI", "PingFang SC", "Microsoft YaHei", Roboto, Helvetica, Arial, sans-serif;
  background: var(--color-bg);
  color: var(--color-text);
  line-height: 1.5;
}

a { color: var(--color-primary); text-decoration: none; }
a:hover { text-decoration: underline; }

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 1.25rem 1rem 3rem;
}

.site-header {
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  position: sticky;
  top: 0;
  z-index: 20;
}

.nav-wrap {
  max-width: var(--max-width);
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.75rem 1rem;
  position: relative;
}

.brand { font-weight: 700; font-size: 1.15rem; color: var(--color-text); }
.brand:hover { text-decoration: none; }

.nav-toggle {
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  width: 26px;
  height: 20px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0;
}
.nav-toggle span { display: block; height: 2px; background: var(--color-text); border-radius: 2px; }

.main-nav { display: flex; align-items: center; gap: 1rem; flex-wrap: wrap; }

.lang-switch a {
  margin-left: 0.35rem;
  font-size: 0.8rem;
  color: var(--color-muted);
  border: 1px solid var(--color-border);
  padding: 0.15rem 0.4rem;
  border-radius: 4px;
}
.lang-switch a.active { background: var(--color-primary); color: #fff; border-color: var(--color-primary); }

@media (max-width: 720px) {
  .nav-toggle { display: flex; }
  .main-nav {
    display: none;
    flex-direction: column;
    align-items: flex-start;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: var(--color-surface);
    border-bottom: 1px solid var(--color-border);
    padding: 0.75rem 1rem 1rem;
  }
  .main-nav.open { display: flex; }
  .lang-switch { margin-top: 0.5rem; }
}

.card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 1.25rem;
  margin-bottom: 1.25rem;
}

h1, h2, h3 { line-height: 1.25; }

.form-group { margin-bottom: 1rem; }
label { display: block; font-weight: 600; margin-bottom: 0.3rem; font-size: 0.9rem; }
input[type="text"], input[type="email"], input[type="password"],
input[type="number"], input[type="date"], input[type="time"], select {
  width: 100%;
  padding: 0.55rem 0.65rem;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  font-size: 1rem;
  background: #fff;
  color: var(--color-text);
}
input:focus, select:focus { outline: 2px solid var(--color-primary); outline-offset: 1px; }
.checkbox-row { display: flex; align-items: center; gap: 0.5rem; }
.checkbox-row label { margin: 0; font-weight: 500; }

.form-row { display: flex; flex-wrap: wrap; gap: 1rem; }
.form-row > .form-group { flex: 1 1 220px; }

.btn {
  display: inline-block;
  background: var(--color-primary);
  color: #fff;
  border: none;
  padding: 0.6rem 1.1rem;
  border-radius: var(--radius);
  font-size: 1rem;
  cursor: pointer;
}
.btn:hover { background: var(--color-primary-dark); text-decoration: none; color: #fff; }
.btn-secondary { background: var(--color-muted); }
.btn-danger { background: var(--color-danger); }
.btn-sm { padding: 0.35rem 0.7rem; font-size: 0.85rem; }

.alert { padding: 0.75rem 1rem; border-radius: var(--radius); margin-bottom: 1rem; font-size: 0.95rem; }
.alert-error { background: #fee2e2; color: #991b1b; }
.alert-success { background: #dcfce7; color: #166534; }

.table-scroll { overflow-x: auto; }
table { width: 100%; border-collapse: collapse; font-size: 0.9rem; min-width: 640px; }
th, td { padding: 0.5rem 0.6rem; border-bottom: 1px solid var(--color-border); text-align: left; white-space: nowrap; }
th { background: #f3f4f6; }

.actions-row { display: flex; gap: 0.5rem; margin-bottom: 1rem; flex-wrap: wrap; }

.summary-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(160px, 1fr)); gap: 0.75rem; margin: 1rem 0; }
.summary-item { background: #f3f4f6; border-radius: var(--radius); padding: 0.75rem; }
.summary-item .value { font-size: 1.25rem; font-weight: 700; }
.summary-item .label { font-size: 0.8rem; color: var(--color-muted); }

.badge { display: inline-block; padding: 0.1rem 0.5rem; border-radius: 999px; font-size: 0.75rem; }
.badge-admin { background: #ede9fe; color: #5b21b6; }
.badge-user { background: #e5e7eb; color: #374151; }

.site-footer { background: #111827; color: #d1d5db; padding: 1.5rem 0; margin-top: 2rem; }
.site-footer .disclaimer { font-size: 0.8rem; color: #9ca3af; margin: 0 0 0.5rem; }
.site-footer .footer-note { font-size: 0.75rem; color: #6b7280; margin: 0; }

/* Homepage */
.hero { text-align: center; padding: 2.5rem 1rem 2rem; }
.hero-eyebrow {
  display: inline-block;
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.02em;
  color: var(--color-primary);
  background: #eff6ff;
  border-radius: 999px;
  padding: 0.25rem 0.75rem;
  margin-bottom: 1rem;
}
.hero h1 { font-size: 2rem; margin: 0 0 0.75rem; line-height: 1.25; }
.hero-subtitle { max-width: 640px; margin: 0 auto 1.25rem; color: var(--color-muted); font-size: 1.05rem; }
.hero .actions-row { justify-content: center; margin-bottom: 0.75rem; }
.hero-trust { font-size: 0.8rem; color: var(--color-muted); }

.features { padding: 2rem 0; }
.features h2, .screenshots h2 { text-align: center; font-size: 1.5rem; margin-bottom: 1.5rem; }
.feature-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 1rem; }
.feature-card { background: var(--color-surface); border: 1px solid var(--color-border); border-radius: var(--radius); padding: 1.25rem; }
.feature-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 48px;
  height: 48px;
  border-radius: 12px;
  background: #eff6ff;
  margin-bottom: 0.75rem;
}
.feature-card h3 { margin: 0 0 0.4rem; font-size: 1.05rem; }
.feature-card p { margin: 0; color: var(--color-muted); font-size: 0.9rem; }

.screenshots { padding: 2rem 0; }
.screenshot-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(320px, 1fr)); gap: 1.5rem; }
.screenshot-figure { margin: 0; }
.screenshot-frame {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 0.75rem;
  box-shadow: 0 8px 24px -12px rgba(15, 23, 42, 0.18);
}
.screenshot-frame svg { display: block; width: 100%; height: auto; }
.screenshot-figure figcaption { margin-top: 0.75rem; color: var(--color-muted); font-size: 0.9rem; text-align: center; }

.cta-band {
  text-align: center;
  background: var(--color-primary);
  color: #fff;
  border-radius: var(--radius);
  padding: 2.5rem 1.5rem;
  margin: 2rem 0;
}
.cta-band h2 { margin: 0 0 0.5rem; font-size: 1.5rem; }
.cta-band p { margin: 0 0 1.25rem; opacity: 0.9; }
.cta-band .btn { background: #fff; color: var(--color-primary); }
.cta-band .btn:hover { background: #f1f5f9; }

@media (max-width: 480px) {
  .container { padding: 1rem 0.75rem 2rem; }
  .card { padding: 1rem; }
  .hero h1 { font-size: 1.5rem; }
}