:root {
  --blue: #2563eb;
  --blue-dark: #1d4ed8;
  --blue-light: #eff6ff;
  --green: #16a34a;
  --red: #dc2626;
  --amber: #b45309;
  --amber-bg: #fffbeb;
  --text: #0f172a;
  --muted: #64748b;
  --border: #e2e8f0;
  --bg: #f8fafc;
  --card: #ffffff;
  --radius: 14px;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.6;
}

.container {
  max-width: 860px;
  margin: 0 auto;
  padding: 0 20px;
}

/* ---------- header ---------- */
.site-header {
  background: var(--card);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 10;
}
.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 58px;
}
.logo {
  font-weight: 800;
  font-size: 20px;
  color: var(--text);
  text-decoration: none;
  letter-spacing: -0.5px;
}
.logo-arrow { color: var(--blue); }
.nav a {
  color: var(--muted);
  text-decoration: none;
  font-size: 14px;
  margin-left: 22px;
}
.nav a:hover { color: var(--blue); }
@media (max-width: 560px) {
  .nav a { margin-left: 14px; font-size: 13px; }
}

/* ---------- hero ---------- */
.hero {
  padding: 44px 0 10px;
  text-align: center;
}
.hero h1 {
  font-size: 32px;
  margin: 0 0 10px;
  letter-spacing: -0.5px;
}
.hero-sub {
  color: var(--muted);
  font-size: 16.5px;
  max-width: 620px;
  margin: 0 auto;
}
@media (max-width: 560px) {
  .hero { padding-top: 30px; }
  .hero h1 { font-size: 25px; }
  .hero-sub { font-size: 15px; }
}

/* ---------- dropzone ---------- */
.dropzone {
  margin: 30px auto 0;
  max-width: 640px;
  background: var(--card);
  border: 2px dashed #b6c6e3;
  border-radius: var(--radius);
  padding: 44px 24px;
  text-align: center;
  cursor: pointer;
  transition: border-color .15s, background .15s;
}
.dropzone:hover, .dropzone:focus-visible {
  border-color: var(--blue);
  outline: none;
}
.dropzone.dragover {
  border-color: var(--blue);
  background: var(--blue-light);
}
.dz-icon { width: 42px; height: 42px; color: var(--blue); }
.dz-title { font-size: 17px; font-weight: 600; margin: 10px 0 2px; }
.dz-sub { color: var(--muted); font-size: 14px; margin: 0; }
.dz-browse { color: var(--blue); font-weight: 600; }

/* ---------- error banner ---------- */
.error-banner {
  margin: 24px auto 0;
  max-width: 640px;
  background: var(--amber-bg);
  border: 1px solid #fcd34d;
  color: var(--amber);
  border-radius: 10px;
  padding: 12px 16px;
  font-size: 14px;
}

/* ---------- file list ---------- */
.file-list {
  max-width: 640px;
  margin: 18px auto 0;
  display: flex;
  flex-direction: column;
  gap: 10px;
}
.file-item {
  display: flex;
  align-items: center;
  gap: 12px;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 10px 12px;
}
.file-thumb {
  width: 52px;
  height: 52px;
  border-radius: 8px;
  object-fit: cover;
  background: var(--blue-light);
  flex: 0 0 auto;
}
.file-thumb.placeholder {
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--blue);
  font-weight: 700;
  font-size: 11px;
}
.file-info { flex: 1; min-width: 0; }
.file-name {
  font-size: 14px;
  font-weight: 600;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.file-meta { font-size: 12.5px; color: var(--muted); }
.status-done { color: var(--green); font-weight: 600; }
.status-error { color: var(--red); font-weight: 600; }
.status-working { color: var(--amber); font-weight: 600; }

/* ---------- buttons ---------- */
.btn {
  border: none;
  border-radius: 10px;
  padding: 10px 18px;
  font-size: 14.5px;
  font-weight: 600;
  cursor: pointer;
  font-family: inherit;
}
.btn-primary {
  background: var(--blue);
  color: #fff;
}
.btn-primary:hover { background: var(--blue-dark); }
.btn-small {
  padding: 7px 14px;
  font-size: 13px;
  border-radius: 8px;
  background: var(--blue-light);
  color: var(--blue-dark);
}
.btn-small:hover { background: #dbeafe; }
.btn-ghost {
  background: transparent;
  border: 1px solid var(--border);
  color: var(--muted);
}
.btn-ghost:hover { border-color: var(--blue); color: var(--blue); }
.list-actions {
  max-width: 640px;
  margin: 14px auto 0;
  display: flex;
  justify-content: space-between;
  gap: 10px;
  flex-wrap: wrap;
}
.list-actions [hidden] { display: none; }

/* ---------- features ---------- */
.features {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 14px;
  margin-top: 48px;
}
.feature-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 18px;
}
.feature-card h3 { margin: 8px 0 4px; font-size: 15px; }
.feature-card p { margin: 0; color: var(--muted); font-size: 13.5px; }
.feature-emoji { font-size: 22px; }

/* ---------- text sections ---------- */
.section { margin-top: 44px; }
.section h2 { font-size: 22px; letter-spacing: -0.3px; }
.steps li { margin-bottom: 10px; }
.faq-item {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 14px 18px;
  margin-bottom: 10px;
}
.faq-item h3 { margin: 0 0 6px; font-size: 15px; }
.faq-item p { margin: 0; color: var(--muted); font-size: 14px; }
.section p { color: #334155; }

/* ---------- footer ---------- */
.site-footer {
  margin-top: 56px;
  border-top: 1px solid var(--border);
  background: var(--card);
  padding: 22px 0 28px;
  text-align: center;
  font-size: 13.5px;
  color: var(--muted);
}
.footer-muted { opacity: .75; margin: 4px 0 0; font-size: 12.5px; }
.footer-muted a { color: inherit; }
.site-footer a:hover { color: var(--blue); }
.section h2 { margin-top: 26px; font-size: 18px; }
.text-muted { color: var(--muted); font-size: 13.5px; }
.section a { color: var(--blue); }