:root {
  --bg: #0f172a;
  --panel: #1e293b;
  --panel-light: #f8fafc;
  --text: #e2e8f0;
  --accent: #6366f1;
  --accent-dark: #4f46e5;
  --border: #334155;
}

* { box-sizing: border-box; }

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

.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.75rem 1.5rem;
  background: var(--panel);
  border-bottom: 1px solid var(--border);
  flex-wrap: wrap;
  gap: 0.5rem;
}

.brand {
  font-weight: 700;
  font-size: 1.25rem;
  color: var(--accent);
  text-decoration: none;
}

.topbar nav a {
  color: var(--text);
  text-decoration: none;
  margin-left: 1.25rem;
  font-size: 0.95rem;
}

.topbar nav a:hover { color: var(--accent); }

main {
  max-width: 1200px;
  margin: 0 auto;
  padding: 1.5rem;
}

.hero { text-align: center; padding: 2rem 1rem; }
.hero h1 { font-size: 2.5rem; margin-bottom: 0.5rem; }
.subtitle { color: #94a3b8; max-width: 640px; margin: 0 auto; }
.subtitle a { color: var(--accent); }

.cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 1rem;
  margin-top: 2rem;
}

.card {
  display: block;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 1.25rem;
  text-decoration: none;
  color: var(--text);
  transition: transform 0.15s, border-color 0.15s;
}

.card:hover { transform: translateY(-2px); border-color: var(--accent); }
.card h2 { margin: 0 0 0.5rem; font-size: 1.1rem; color: var(--accent); }
.card p { margin: 0; color: #94a3b8; font-size: 0.9rem; }

.page-title { margin-bottom: 0.25rem; }
.hint { color: #94a3b8; margin-top: 0; font-size: 0.9rem; }
.hint code { background: #1e293b; padding: 0.1rem 0.35rem; border-radius: 4px; }

.editor-layout {
  display: grid;
  grid-template-columns: 180px 1fr 320px;
  gap: 1rem;
  margin-top: 1rem;
}

.toolbar {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}

.toolbar hr { border-color: var(--border); width: 100%; }

.tool-btn, .toolbar button, .button-row button, #btn-run, #btn-generate {
  background: var(--panel);
  border: 1px solid var(--border);
  color: var(--text);
  padding: 0.5rem 0.6rem;
  border-radius: 8px;
  cursor: pointer;
  font-size: 0.9rem;
  text-align: left;
}

.tool-btn:hover, .toolbar button:hover { border-color: var(--accent); }
.tool-btn.active { background: var(--accent-dark); border-color: var(--accent-dark); color: white; }

button.primary, .primary {
  background: var(--accent-dark) !important;
  border-color: var(--accent-dark) !important;
  color: white !important;
}

.canvas {
  height: 560px;
  background: var(--panel-light);
  border-radius: 10px;
  border: 1px solid var(--border);
}

.sidebar {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.sidebar label, .panel label { font-size: 0.85rem; color: #94a3b8; }

.sidebar input, .panel input, .panel textarea {
  background: var(--panel);
  border: 1px solid var(--border);
  color: var(--text);
  padding: 0.5rem;
  border-radius: 8px;
  font-family: inherit;
  width: 100%;
}

.panel textarea { font-family: "SFMono-Regular", Consolas, monospace; }

.result { margin-top: 0.5rem; min-height: 1.5rem; }

.badge {
  display: inline-block;
  padding: 0.2rem 0.6rem;
  border-radius: 999px;
  font-size: 0.85rem;
  font-weight: 600;
}

.badge.ok { background: #064e3b; color: #6ee7b7; }
.badge.bad { background: #450a0a; color: #fca5a5; }
.badge.warn { background: #451a03; color: #fdba74; margin-left: 0.4rem; }

.trace-list, .output {
  margin-top: 0.5rem;
  max-height: 420px;
  overflow-y: auto;
  font-family: "SFMono-Regular", Consolas, monospace;
  font-size: 0.85rem;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.5rem;
}

.trace-row { padding: 0.25rem 0.35rem; border-radius: 6px; cursor: pointer; }
.trace-row:hover { background: rgba(99, 102, 241, 0.2); }
.trace-summary { margin-top: 0.4rem; color: #94a3b8; }

.grammar-layout {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
  margin-top: 1rem;
}

.panel {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 1rem;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.button-row { display: flex; gap: 0.5rem; flex-wrap: wrap; }
.button-row button { text-align: center; }

@media (max-width: 900px) {
  .editor-layout { grid-template-columns: 1fr; }
  .grammar-layout { grid-template-columns: 1fr; }
  .toolbar { flex-direction: row; flex-wrap: wrap; }
}

/* ---------------------------------------------------------------- Auth */
.login-container {
  max-width: 380px;
  margin: 3rem auto;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 2rem;
}

.login-container h1 { margin-top: 0; text-align: center; }

.login-container form {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}

.login-container button {
  margin-top: 1rem;
  background: var(--accent-dark);
  border: none;
  color: white;
  padding: 0.6rem;
  border-radius: 8px;
  cursor: pointer;
  font-size: 1rem;
}

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

.error-message {
  background: #450a0a;
  color: #fca5a5;
  padding: 0.6rem 0.8rem;
  border-radius: 8px;
  font-size: 0.9rem;
  text-align: center;
}

.user-box {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  margin-left: auto;
}

.user-name { color: #94a3b8; font-size: 0.9rem; }

.logout-form { display: inline; margin: 0; }

.logout-btn {
  background: transparent;
  border: 1px solid var(--border);
  color: var(--text);
  padding: 0.3rem 0.7rem;
  border-radius: 8px;
  cursor: pointer;
  font-size: 0.85rem;
}

.logout-btn:hover { border-color: var(--accent); color: var(--accent); }