:root {
  --bg: #fafafa;
  --bg-secondary: #f4f4f5;
  --border: #d4d4d8;
  --text: #18181b;
  --text-secondary: #52525b;
  --accent: #2563eb;
  --accent-hover: #1d4ed8;
  --accent-subtle: #eff6ff;
  --danger: #dc2626;
  --success: #16a34a;
  --time-orig: #d97706;
  --time-adj: #16a34a;
  --radius: 0.5rem;
  --radius-lg: 0.75rem;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #09090b;
    --bg-secondary: #18181b;
    --border: #3f3f46;
    --text: #fafafa;
    --text-secondary: #a1a1aa;
    --accent: #60a5fa;
    --accent-hover: #93c5fd;
    --accent-subtle: #1e3a5f;
    --danger: #f87171;
    --success: #4ade80;
    --time-orig: #fbbf24;
    --time-adj: #4ade80;
  }
}

[data-theme="light"] {
  --bg: #fafafa; --bg-secondary: #f4f4f5; --border: #d4d4d8;
  --text: #18181b; --text-secondary: #52525b; --accent: #2563eb;
  --accent-hover: #1d4ed8; --accent-subtle: #eff6ff;
}
[data-theme="dark"] {
  --bg: #09090b; --bg-secondary: #18181b; --border: #3f3f46;
  --text: #fafafa; --text-secondary: #a1a1aa; --accent: #60a5fa;
  --accent-hover: #93c5fd; --accent-subtle: #1e3a5f;
}

*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100dvh;
  padding: 1rem;
}

.container {
  width: 100%;
  max-width: 44rem;
  margin-inline: auto;
}

h1 {
  font-family: Georgia, "Times New Roman", Times, serif;
  font-size: 1.75rem;
  font-weight: 700;
  letter-spacing: -0.01em;
  margin-bottom: 0.25rem;
}

.subtitle {
  color: var(--text-secondary);
  margin-bottom: 1.5rem;
  font-size: 0.9rem;

  & code {
    font-family: ui-monospace, "SF Mono", Menlo, monospace;
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    padding: 0.1em 0.35em;
    border-radius: 4px;
    font-size: 0.85em;
  }
}

/* Upload zone */
.upload-zone {
  border: 2px dashed var(--border);
  border-radius: var(--radius-lg);
  padding: 2.5rem 1rem;
  text-align: center;
  cursor: pointer;
  transition: border-color 0.15s, background 0.15s;

  &:hover, &.drag-over {
    border-color: var(--accent);
    background: var(--accent-subtle);
  }
}

.upload-inner {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.5rem;
  pointer-events: none;

  & p { color: var(--text-secondary); font-size: 0.9rem; }
  & strong { color: var(--text); }
}

.upload-icon {
  width: 2.5rem;
  height: 2.5rem;
  color: var(--text-secondary);
  margin-bottom: 0.25rem;
}

.file-label {
  color: var(--accent);
  cursor: pointer;
  text-decoration: underline;
  pointer-events: all;
}

.hint {
  font-size: 0.78rem;
  color: var(--text-secondary);
  opacity: 0.75;
}

/* Tool panel */
.tool-panel {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.file-info {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  flex-wrap: wrap;
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 0.6rem 0.875rem;
}

.file-name {
  font-weight: 600;
  font-family: ui-monospace, "SF Mono", Menlo, monospace;
  font-size: 0.85rem;
  color: var(--accent);
}

.file-meta {
  color: var(--text-secondary);
  font-size: 0.8rem;
  flex: 1;
}

/* Adjustment panel */
.adjustment-panel {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 1.25rem;
  display: flex;
  flex-direction: column;
  gap: 1.125rem;
}

.offset-display {
  display: flex;
  align-items: baseline;
  gap: 0.625rem;
}

.offset-label {
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-secondary);
}

.offset-value {
  font-family: ui-monospace, "SF Mono", Menlo, monospace;
  font-size: 1.75rem;
  font-weight: 700;
  color: var(--accent);
  letter-spacing: -0.02em;
}

/* Slider */
.slider-row {
  display: flex;
  align-items: center;
  gap: 0.625rem;
}

.slider-bound {
  font-size: 0.75rem;
  color: var(--text-secondary);
  white-space: nowrap;
  font-family: ui-monospace, "SF Mono", Menlo, monospace;
}

input[type="range"] {
  flex: 1;
  height: 6px;
  cursor: pointer;
  accent-color: var(--accent);
  border-radius: 3px;
}

/* Presets */
.presets, .fine-tune {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.presets-label, .fine-label {
  font-size: 0.72rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-secondary);
}

.preset-btns, .fine-btns {
  display: flex;
  flex-wrap: wrap;
  gap: 0.375rem;
}

/* Exact input */
.exact-row {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  flex-wrap: wrap;

  & label {
    font-size: 0.8rem;
    color: var(--text-secondary);
    white-space: nowrap;
  }

  & input {
    font-family: ui-monospace, "SF Mono", Menlo, monospace;
    font-size: 0.9rem;
    width: 9rem;
    padding: 0.375rem 0.625rem;
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    color: var(--text);
    transition: border-color 0.15s;

    &:focus {
      outline: none;
      border-color: var(--accent);
    }
  }
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.45rem 0.875rem;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--bg);
  color: var(--text);
  font-size: 0.85rem;
  font-family: inherit;
  cursor: pointer;
  transition: background 0.12s, border-color 0.12s, color 0.12s;
  white-space: nowrap;

  &:hover {
    background: var(--bg-secondary);
    border-color: var(--accent);
  }

  &:active {
    transform: scale(0.97);
  }
}

.btn-sm {
  padding: 0.3rem 0.625rem;
  font-size: 0.78rem;
}

.btn-ghost {
  border-color: transparent;
  background: transparent;
  color: var(--text-secondary);
  font-size: 0.78rem;

  &:hover {
    color: var(--text);
    background: var(--bg-secondary);
    border-color: var(--border);
  }
}

.btn-primary {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
  font-weight: 600;
  padding: 0.6rem 1.5rem;
  font-size: 0.9rem;

  &:hover {
    background: var(--accent-hover);
    border-color: var(--accent-hover);
    color: #fff;
  }
}

/* Preview */
.preview-panel {
  & h2 {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 0.75rem;
  }

  & .preview-count {
    font-size: 0.78rem;
    font-weight: 400;
    color: var(--text-secondary);
    margin-left: 0.25rem;
  }
}

.preview-list {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  max-height: 18rem;
  overflow-y: auto;
  scrollbar-width: thin;
  scrollbar-color: var(--border) transparent;
}

.preview-item {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 0.625rem 0.875rem;
  display: grid;
  gap: 0.2rem;
}

.preview-seq {
  font-size: 0.7rem;
  color: var(--text-secondary);
  font-family: ui-monospace, "SF Mono", Menlo, monospace;
}

.preview-time {
  font-family: ui-monospace, "SF Mono", Menlo, monospace;
  font-size: 0.82rem;
}

.preview-time--orig {
  color: var(--time-orig);
}

.preview-time--stale {
  color: var(--time-orig);
  text-decoration: line-through;
  opacity: 0.6;
  font-size: 0.76rem;
}

.preview-time--adj {
  color: var(--time-adj);
}

.preview-text {
  font-size: 0.85rem;
  color: var(--text);
  line-height: 1.4;
  white-space: pre-wrap;
}

.preview-clipped {
  text-align: center;
  padding: 0.5rem;
  color: var(--text-secondary);
  font-size: 0.8rem;
  font-style: italic;
}

/* Actions */
.actions {
  display: flex;
  justify-content: flex-end;
}

@media (min-width: 640px) {
  body { padding: 2rem; }

  .fine-btns {
    flex-wrap: nowrap;
  }
}