:root {
  --bg: #0f1115;
  --surface: #1a1d24;
  --surface-2: #232730;
  --border: #2d323d;
  --text: #e6e8ec;
  --text-dim: #9aa3b2;
  --primary: #6366f1;
  --primary-hover: #4f46e5;
  --accent: #22d3ee;
  --warn: #f59e0b;
  --danger: #ef4444;
  --radius: 10px;
  --shadow: 0 4px 20px rgba(0,0,0,0.35);
}
[data-theme="light"] {
  --bg: #f5f7fa;
  --surface: #ffffff;
  --surface-2: #f0f2f6;
  --border: #d9dde4;
  --text: #1a1d24;
  --text-dim: #5b6472;
  --shadow: 0 4px 20px rgba(0,0,0,0.08);
}
* { box-sizing: border-box; }
body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  transition: background 0.2s, color 0.2s;
}
.container { max-width: 960px; margin: 0 auto; padding: 0 20px; width: 100%; }
header {
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  padding: 16px 0;
}
.header-bar {
  display: flex; justify-content: space-between; align-items: center;
}
h1 { margin: 0; font-size: 1.5rem; background: linear-gradient(135deg, var(--primary), var(--accent)); -webkit-background-clip: text; background-clip: text; color: transparent; }
.theme-btn {
  background: var(--surface-2);
  border: 1px solid var(--border);
  color: var(--text);
  width: 40px; height: 40px;
  border-radius: 50%;
  cursor: pointer;
  font-size: 18px;
  transition: transform 0.2s;
}
.theme-btn:hover { transform: rotate(20deg); }

main { flex: 1; padding: 24px 0; }

.tabs {
  display: flex; flex-wrap: wrap; gap: 6px;
  margin-bottom: 20px;
  border-bottom: 1px solid var(--border);
}
.tab {
  background: transparent;
  border: none;
  color: var(--text-dim);
  padding: 10px 18px;
  cursor: pointer;
  font-size: 14px;
  font-weight: 500;
  border-bottom: 2px solid transparent;
  transition: all 0.2s;
}
.tab:hover { color: var(--text); }
.tab.active {
  color: var(--primary);
  border-bottom-color: var(--primary);
}

.panel {
  display: none;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  box-shadow: var(--shadow);
  animation: fadeIn 0.25s ease;
}
.panel.active { display: block; }
@keyframes fadeIn { from { opacity: 0; transform: translateY(4px); } to { opacity: 1; transform: none; } }

.panel h2 { margin-top: 0; font-size: 1.25rem; }
.hint { color: var(--text-dim); font-size: 13px; margin-top: -4px; }
.hint.warn { color: var(--warn); }

label {
  display: block;
  font-size: 13px;
  font-weight: 500;
  color: var(--text-dim);
  margin-top: 14px;
}
input, select, textarea {
  width: 100%;
  margin-top: 6px;
  padding: 10px 12px;
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: 8px;
  color: var(--text);
  font-family: inherit;
  font-size: 14px;
  transition: border-color 0.2s;
}
textarea { font-family: ui-monospace, "SF Mono", Menlo, monospace; resize: vertical; }
input:focus, select:focus, textarea:focus {
  outline: none;
  border-color: var(--primary);
}

.row { display: flex; gap: 12px; align-items: flex-end; flex-wrap: wrap; }
.row > label { flex: 1; min-width: 150px; }

.actions { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 16px; }
.btn {
  padding: 10px 18px;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: var(--surface-2);
  color: var(--text);
  cursor: pointer;
  font-size: 14px;
  font-weight: 500;
  transition: all 0.15s;
}
.btn:hover { border-color: var(--primary); }
.btn.primary {
  background: var(--primary);
  border-color: var(--primary);
  color: white;
}
.btn.primary:hover { background: var(--primary-hover); }
.btn.ghost { background: transparent; }

footer {
  background: var(--surface);
  border-top: 1px solid var(--border);
  padding: 16px 0;
  text-align: center;
  color: var(--text-dim);
  font-size: 13px;
}
footer a { color: var(--primary); text-decoration: none; font-weight: 500; }
footer a:hover { text-decoration: underline; }

@media (max-width: 600px) {
  .tab { padding: 8px 12px; font-size: 13px; }
  .panel { padding: 16px; }
  h1 { font-size: 1.2rem; }
}