:root {
  --bg: #0f1117;
  --bg-card: #1a1d26;
  --bg-input: #242833;
  --border: #2e3340;
  --text: #e8eaf0;
  --text-dim: #9aa0ae;
  --accent: #f5c518;
  --accent-hover: #ffd84d;
  --danger: #e5484d;
  --active-border: #f5c518;
  --active-bg: rgba(245, 197, 24, 0.12);
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang HK",
    "Microsoft JhengHei", "Noto Sans TC", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  min-height: 100vh;
}

main {
  max-width: 720px;
  margin: 0 auto;
  padding: 0 1rem 3rem;
}

/* ===== Header ===== */

.app-header {
  text-align: center;
  padding: 2.5rem 1rem 1.5rem;
}

.app-header h1 {
  font-size: 1.8rem;
  letter-spacing: 0.08em;
}

.tagline {
  color: var(--text-dim);
  margin-top: 0.25rem;
  font-size: 0.95rem;
}

.app-footer {
  text-align: center;
  color: var(--text-dim);
  font-size: 0.8rem;
  padding: 2rem 1rem;
}

/* ===== Card & buttons ===== */

.card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 1.5rem;
  margin-bottom: 1.5rem;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.btn {
  border: none;
  border-radius: 8px;
  padding: 0.75rem 1.25rem;
  font-size: 1rem;
  cursor: pointer;
  transition: background 0.15s ease, opacity 0.15s ease;
}

.btn:disabled {
  opacity: 0.45;
  cursor: not-allowed;
}

.btn-primary {
  background: var(--accent);
  color: #000;
  font-weight: 600;
}

.btn-primary:not(:disabled):hover {
  background: var(--accent-hover);
}

.btn-secondary {
  background: var(--bg-input);
  color: var(--text);
  border: 1px solid var(--border);
}

.btn-secondary:not(:disabled):hover {
  border-color: var(--accent);
  color: var(--accent);
}

.btn-export {
  background: var(--accent);
  color: #000;
  font-weight: 600;
}

.btn-export:not(:disabled):hover {
  background: var(--accent-hover);
}

/* ===== File input ===== */

input[type="file"] {
  display: block;
  width: 100%;
  padding: 0.75rem;
  background: var(--bg-input);
  border: 1px dashed var(--border);
  border-radius: 8px;
  color: var(--text);
  font-size: 0.9rem;
}

.file-name {
  color: var(--text-dim);
  font-size: 0.9rem;
  word-break: break-all;
}

/* ===== Progress & status ===== */

progress {
  width: 100%;
  height: 10px;
  border-radius: 999px;
  overflow: hidden;
  appearance: none;
  -webkit-appearance: none;
}

progress::-webkit-progress-bar {
  background: var(--bg-input);
}

progress::-webkit-progress-value {
  background: var(--accent);
  border-radius: 999px;
}

progress::-moz-progress-bar {
  background: var(--accent);
}

.status-msg {
  font-size: 0.95rem;
  color: var(--text-dim);
}

.status-msg.error {
  color: var(--danger);
}

.status-msg .btn {
  display: block;
}

/* ===== Editor ===== */

.editor {
  margin-bottom: 1.5rem;
}

.editor video {
  width: 100%;
  border-radius: 12px;
  background: #000;
  margin-bottom: 1rem;
}

.caption-toolbar {
  display: flex;
  justify-content: flex-end;
  margin-bottom: 0.75rem;
}

.caption-list {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  max-height: 420px;
  overflow-y: auto;
  padding-right: 0.25rem;
}

.caption-row {
  display: grid;
  grid-template-columns: 72px 20px 72px 1fr auto;
  align-items: center;
  gap: 0.4rem;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.5rem;
  cursor: pointer;
  transition: border-color 0.15s ease, background 0.15s ease;
}

.caption-row.active {
  border-color: var(--active-border);
  background: var(--active-bg);
}

.caption-row .time-input,
.caption-row .caption-text {
  background: var(--bg-input);
  border: 1px solid var(--border);
  border-radius: 6px;
  color: var(--text);
  font-size: 0.9rem;
  padding: 0.35rem 0.45rem;
  min-width: 0;
}

.caption-row .time-input {
  width: 100%;
  font-variant-numeric: tabular-nums;
}

.caption-row .caption-text {
  resize: vertical;
  font-family: inherit;
}

.caption-row .time-sep {
  color: var(--text-dim);
  text-align: center;
  font-size: 0.85rem;
}

.caption-row .btn-del {
  background: transparent;
  border: 1px solid var(--border);
  color: var(--danger);
  border-radius: 6px;
  padding: 0.35rem 0.6rem;
  font-size: 0.85rem;
  cursor: pointer;
}

.caption-row .btn-del:hover {
  border-color: var(--danger);
  background: rgba(229, 72, 77, 0.12);
}

/* ===== Responsive ===== */

@media (max-width: 520px) {
  .app-header h1 {
    font-size: 1.4rem;
  }

  .card {
    padding: 1rem;
  }

  .caption-row {
    grid-template-columns: 1fr;
    gap: 0.4rem;
  }

  .caption-row .time-sep {
    display: none;
  }
}