:root {
  color-scheme: light dark;
  --bg: #f5f6f8;
  --card-bg: #ffffff;
  --text: #1c1f24;
  --muted: #6b7280;
  --border: #e2e5ea;
  --accent: #2563eb;
  --accent-hover: #1d4ed8;
  --error-bg: #fef2f2;
  --error-text: #b91c1c;
  --success-bg: #f0fdf4;
  --success-text: #15803d;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #14161a;
    --card-bg: #1e2126;
    --text: #e8eaed;
    --muted: #9aa0a6;
    --border: #33363c;
    --accent: #4d8dff;
    --accent-hover: #6ba1ff;
    --error-bg: #3a1f1f;
    --error-text: #ff8080;
    --success-bg: #163a22;
    --success-text: #4ade80;
  }
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Hiragino Sans", "Yu Gothic", sans-serif;
  padding: 24px;
}

.card {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 32px;
  width: 100%;
  max-width: 440px;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.08);
}

h1 {
  font-size: 1.25rem;
  margin: 0 0 20px;
}

.subtitle {
  color: var(--muted);
  font-size: 0.875rem;
  margin: -12px 0 20px;
}

label {
  display: block;
  font-size: 0.875rem;
  margin-bottom: 6px;
  color: var(--muted);
}

input[type="text"],
input[type="password"],
input[type="file"] {
  width: 100%;
  padding: 10px 12px;
  margin-bottom: 16px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: transparent;
  color: var(--text);
  font-size: 0.95rem;
}

button, .btn {
  display: inline-block;
  width: 100%;
  padding: 11px 16px;
  background: var(--accent);
  color: #fff;
  border: none;
  border-radius: 8px;
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  text-align: center;
  text-decoration: none;
  transition: background 0.15s ease;
}

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

button:disabled {
  opacity: 0.6;
  cursor: not-allowed;
}

.error {
  background: var(--error-bg);
  color: var(--error-text);
  padding: 10px 14px;
  border-radius: 8px;
  font-size: 0.875rem;
  margin-bottom: 16px;
}

.success {
  background: var(--success-bg);
  color: var(--success-text);
  padding: 10px 14px;
  border-radius: 8px;
  font-size: 0.875rem;
  margin-bottom: 16px;
}

.top-bar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 20px;
}

.top-bar .logout {
  font-size: 0.8rem;
  color: var(--muted);
  text-decoration: none;
}

.top-bar .logout:hover {
  color: var(--text);
}

.spinner {
  width: 40px;
  height: 40px;
  margin: 24px auto;
  border: 4px solid var(--border);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

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

.status-text {
  text-align: center;
  color: var(--muted);
  font-size: 0.9rem;
}

.status-note {
  text-align: center;
  color: var(--muted);
  font-size: 0.8rem;
  margin-top: 12px;
  line-height: 1.6;
}

.file-list {
  font-size: 0.8rem;
  color: var(--muted);
  margin: -8px 0 16px;
}