/* PDF Split — hand-built design system (no external framework/build step required) */

:root {
  --color-bg: #f4f6fb;
  --color-surface: #ffffff;
  --color-surface-alt: #f8f9fc;
  --color-border: #e2e5ee;
  --color-text: #1c2130;
  --color-text-muted: #626a80;
  --color-primary: #4f46e5;
  --color-primary-hover: #4338ca;
  --color-primary-soft: #eef0ff;
  --color-success: #16a34a;
  --color-danger: #dc2626;
  --color-danger-soft: #fef2f2;
  --shadow-sm: 0 1px 2px rgba(20, 24, 40, 0.06);
  --shadow-md: 0 6px 20px rgba(20, 24, 40, 0.08);
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 20px;
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans Thai", "Sarabun", Roboto, Helvetica, Arial, sans-serif;
}

@media (prefers-color-scheme: dark) {
  :root {
    --color-bg: #0f1117;
    --color-surface: #171a24;
    --color-surface-alt: #1d212c;
    --color-border: #2a2f3d;
    --color-text: #e7e9f2;
    --color-text-muted: #9aa1b5;
    --color-primary: #818cf8;
    --color-primary-hover: #a5b0fb;
    --color-primary-soft: #262a45;
    --color-danger-soft: #3a1e22;
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.4);
    --shadow-md: 0 10px 30px rgba(0, 0, 0, 0.45);
  }
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--color-bg);
  color: var(--color-text);
  font-family: var(--font-sans);
  -webkit-font-smoothing: antialiased;
}

body { min-height: 100vh; }

/* The HTML `hidden` attribute must always win, even over elements whose
   class sets its own `display` (e.g. .progress-area uses display:flex,
   which would otherwise silently override [hidden] at equal specificity
   since author rules beat the UA stylesheet regardless of selector order). */
[hidden] { display: none !important; }

img, svg { display: block; max-width: 100%; }

button, input { font-family: inherit; }

.app-shell {
  max-width: 880px;
  margin: 0 auto;
  padding: 0 20px 60px;
}

/* Header */
.site-header {
  padding: 40px 0 24px;
}
.site-header__brand {
  display: flex;
  align-items: center;
  gap: 14px;
}
.brand-mark {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 48px;
  height: 48px;
  border-radius: var(--radius-md);
  background: var(--color-primary-soft);
  color: var(--color-primary);
  flex-shrink: 0;
}
.site-header h1 {
  margin: 0;
  font-size: 1.5rem;
  font-weight: 800;
  letter-spacing: -0.01em;
}
.tagline {
  margin: 2px 0 0;
  color: var(--color-text-muted);
  font-size: 0.9rem;
}

/* Privacy banner */
.privacy-banner {
  display: flex;
  gap: 10px;
  align-items: flex-start;
  background: var(--color-primary-soft);
  color: var(--color-text);
  border: 1px solid color-mix(in srgb, var(--color-primary) 25%, transparent);
  border-radius: var(--radius-md);
  padding: 14px 16px;
  margin-bottom: 20px;
}
.privacy-banner svg { color: var(--color-primary); flex-shrink: 0; margin-top: 2px; }
.privacy-banner p { margin: 0; font-size: 0.85rem; line-height: 1.55; color: var(--color-text-muted); }
.privacy-banner strong { color: var(--color-text); }

/* Panels */
.panel {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
  padding: 22px;
  margin-bottom: 18px;
}
.panel__header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 14px;
}
.panel__header h2 {
  font-size: 1.05rem;
  margin: 0;
}

/* Dropzone */
.dropzone {
  border: 2px dashed var(--color-border);
  border-radius: var(--radius-md);
  padding: 40px 20px;
  text-align: center;
  cursor: pointer;
  transition: border-color .15s ease, background-color .15s ease;
  color: var(--color-text-muted);
}
.dropzone svg { margin: 0 auto 10px; color: var(--color-primary); }
.dropzone:hover, .dropzone:focus-visible {
  border-color: var(--color-primary);
  background: var(--color-primary-soft);
  outline: none;
}
.dropzone.is-dragover {
  border-color: var(--color-primary);
  background: var(--color-primary-soft);
}
.dropzone__title {
  margin: 0 0 6px;
  font-weight: 600;
  color: var(--color-text);
}
.dropzone__hint {
  margin: 0;
  font-size: 0.8rem;
}

/* File list */
.file-list { list-style: none; margin: 0; padding: 0; display: flex; flex-direction: column; gap: 14px; }
.file-card {
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 14px 16px;
  background: var(--color-surface-alt);
}
.file-card__row { display: flex; align-items: center; gap: 12px; }
.file-card__icon { color: var(--color-primary); flex-shrink: 0; }
.file-card__meta { flex: 1; min-width: 0; }
.file-card__name {
  margin: 0;
  font-weight: 600;
  font-size: 0.92rem;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.file-card__sub {
  margin: 2px 0 0;
  font-size: 0.78rem;
  color: var(--color-text-muted);
}
.file-card__sub.is-error { color: var(--color-danger); }

.file-card__mode {
  display: flex;
  gap: 8px;
  margin-top: 12px;
  flex-wrap: wrap;
}

.chip {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  border: 1px solid var(--color-border);
  border-radius: 999px;
  padding: 6px 12px;
  font-size: 0.8rem;
  cursor: pointer;
  color: var(--color-text-muted);
  transition: all .12s ease;
  user-select: none;
}
.chip:has(input:checked) {
  background: var(--color-primary);
  border-color: var(--color-primary);
  color: #fff;
}
.chip input { accent-color: var(--color-primary); }

.range-builder {
  margin-top: 12px;
  padding-top: 12px;
  border-top: 1px dashed var(--color-border);
}
.range-list { list-style: none; margin: 0 0 10px; padding: 0; display: flex; flex-direction: column; gap: 8px; }
.range-row {
  display: grid;
  grid-template-columns: 1.1fr 1fr auto;
  gap: 8px;
  align-items: center;
}
.range-row__pages, .range-row__label {
  width: 100%;
  padding: 8px 10px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  background: var(--color-surface);
  color: var(--color-text);
  font-size: 0.85rem;
}
.range-row__pages:focus, .range-row__label:focus {
  outline: 2px solid var(--color-primary);
  outline-offset: 1px;
}
.range-row__pages.is-invalid { border-color: var(--color-danger); }

/* Download modes */
.download-modes {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 10px;
}
.mode-card {
  position: relative;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 14px;
  cursor: pointer;
  display: flex;
  flex-direction: column;
  gap: 4px;
  background: var(--color-surface-alt);
  transition: border-color .12s ease, background-color .12s ease;
}
.mode-card input { position: absolute; top: 12px; right: 12px; accent-color: var(--color-primary); }
.mode-card:has(input:checked) {
  border-color: var(--color-primary);
  background: var(--color-primary-soft);
}
.mode-card__title { font-weight: 600; font-size: 0.88rem; padding-right: 20px; }
.mode-card__desc { font-size: 0.76rem; color: var(--color-text-muted); }

.custom-select-panel { margin-top: 16px; }
.hint { font-size: 0.78rem; color: var(--color-text-muted); margin: 0 0 10px; }
.custom-select-list { list-style: none; margin: 0; padding: 0; display: flex; flex-direction: column; gap: 6px; max-height: 260px; overflow-y: auto; }
.custom-select-item label {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.83rem;
  padding: 6px 8px;
  border-radius: var(--radius-sm);
}
.custom-select-item label:hover { background: var(--color-surface-alt); }
.custom-select-item input { accent-color: var(--color-primary); }

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  border: 1px solid transparent;
  border-radius: var(--radius-sm);
  font-weight: 600;
  cursor: pointer;
  transition: background-color .12s ease, border-color .12s ease, opacity .12s ease;
}
.btn:disabled { opacity: 0.5; cursor: not-allowed; }
.btn--primary { background: var(--color-primary); color: #fff; padding: 13px 22px; font-size: 0.95rem; }
.btn--primary:hover:not(:disabled) { background: var(--color-primary-hover); }
.btn--lg { width: 100%; border-radius: var(--radius-md); }
.btn--ghost { background: transparent; border-color: var(--color-border); color: var(--color-text); padding: 8px 14px; }
.btn--ghost:hover { border-color: var(--color-primary); color: var(--color-primary); }
.btn--sm { font-size: 0.78rem; padding: 6px 12px; }

.icon-btn {
  background: transparent;
  border: none;
  color: var(--color-text-muted);
  cursor: pointer;
  font-size: 0.85rem;
  padding: 4px 8px;
  border-radius: var(--radius-sm);
  flex-shrink: 0;
}
.icon-btn:hover { background: var(--color-danger-soft); color: var(--color-danger); }

/* Action bar */
.action-bar { display: flex; flex-direction: column; gap: 12px; margin-top: 8px; }

.error-area {
  background: var(--color-danger-soft);
  color: var(--color-danger);
  border: 1px solid color-mix(in srgb, var(--color-danger) 30%, transparent);
  border-radius: var(--radius-md);
  padding: 12px 14px;
  font-size: 0.85rem;
  white-space: pre-line;
}

.progress-area {
  display: flex;
  align-items: center;
  gap: 10px;
  justify-content: center;
  color: var(--color-text-muted);
  font-size: 0.85rem;
}
.spinner {
  width: 18px;
  height: 18px;
  border: 2.5px solid var(--color-border);
  border-top-color: var(--color-primary);
  border-radius: 50%;
  animation: spin 0.7s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }

/* Footer */
.site-footer {
  margin-top: 30px;
  padding-top: 18px;
  border-top: 1px solid var(--color-border);
  text-align: center;
}
.site-footer p {
  font-size: 0.75rem;
  color: var(--color-text-muted);
  line-height: 1.6;
  margin: 0;
}

@media (max-width: 560px) {
  .range-row { grid-template-columns: 1fr; }
  .site-header { padding-top: 24px; }
}