:root {
  --bg: #f5f6f8;
  --card-bg: #ffffff;
  --text: #1c1e21;
  --text-muted: #6b7280;
  --accent: #2563eb;
  --accent-hover: #1d4ed8;
  --border: #d1d5db;
  --error: #dc2626;
  --success: #16a34a;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #14161a;
    --card-bg: #1e2126;
    --text: #e5e7eb;
    --text-muted: #9ca3af;
    --accent: #3b82f6;
    --accent-hover: #60a5fa;
    --border: #374151;
    --error: #f87171;
    --success: #4ade80;
  }
}

* { box-sizing: border-box; }

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

.wrap {
  max-width: 640px;
  margin: 0 auto;
  padding: 48px 24px;
}

h1 {
  font-size: 1.75rem;
  margin: 0 0 8px;
}

.subtitle {
  color: var(--text-muted);
  margin: 0 0 32px;
  line-height: 1.5;
}

.dropzone {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 160px;
  border: 2px dashed var(--border);
  border-radius: 12px;
  background: var(--card-bg);
  color: var(--text-muted);
  text-align: center;
  padding: 24px;
  cursor: pointer;
  transition: border-color 0.15s, background 0.15s;
}

.dropzone.dragover {
  border-color: var(--accent);
  background: color-mix(in srgb, var(--accent) 8%, var(--card-bg));
}

.dropzone.has-file {
  color: var(--text);
  font-weight: 500;
}

button {
  font: inherit;
}

#submit-btn {
  display: block;
  width: 100%;
  margin-top: 16px;
  padding: 12px;
  border: none;
  border-radius: 8px;
  background: var(--accent);
  color: #fff;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.15s;
}

#submit-btn:disabled {
  background: var(--border);
  color: var(--text-muted);
  cursor: not-allowed;
}

#submit-btn:not(:disabled):hover {
  background: var(--accent-hover);
}

.progress, .result, .error {
  margin-top: 32px;
  padding: 24px;
  border-radius: 12px;
  background: var(--card-bg);
  border: 1px solid var(--border);
}

.spinner {
  width: 28px;
  height: 28px;
  border: 3px solid var(--border);
  border-top-color: var(--accent);
  border-radius: 50%;
  margin: 0 auto 16px;
  animation: spin 0.8s linear infinite;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

#progress-status {
  text-align: center;
  margin: 0 0 12px;
  font-weight: 500;
}

#progress-log {
  max-height: 220px;
  overflow-y: auto;
  background: var(--bg);
  border-radius: 8px;
  padding: 12px;
  font-size: 0.8rem;
  color: var(--text-muted);
  white-space: pre-wrap;
  margin: 0;
}

.result p, .error p {
  margin: 0 0 16px;
}

.error p {
  color: var(--error);
}

.button {
  display: inline-block;
  padding: 10px 18px;
  border-radius: 8px;
  background: var(--accent);
  color: #fff;
  text-decoration: none;
  font-weight: 600;
  border: none;
  cursor: pointer;
  margin-right: 8px;
}

.button:hover {
  background: var(--accent-hover);
}

.button.secondary {
  background: transparent;
  color: var(--text);
  border: 1px solid var(--border);
}

.button.secondary:hover {
  background: var(--bg);
}