/* =========================
   CSS CUSTOM PROPERTIES
   ========================= */
:root {
  --bg: #f4f5f7;
  --bg-card: #ffffff;
  --text: #1f2937;
  --text-muted: #6b7280;
  --border: #e5e7eb;
  --primary: #1f2937;
  --primary-hover: #374151;
  --danger: #ef4444;
  --danger-hover: #dc2626;
  --success: #10b981;
  --radius: 12px;
  --shadow: 0 2px 8px rgba(0,0,0,0.08);
  --nav-bg: #ffffff;
  --input-bg: #ffffff;
}

[data-theme="dark"] {
  --bg: #111827;
  --bg-card: #1f2937;
  --text: #f9fafb;
  --text-muted: #9ca3af;
  --border: #374151;
  --primary: #e5e7eb;
  --primary-hover: #d1d5db;
  --nav-bg: #1f2937;
  --input-bg: #374151;
  --shadow: 0 2px 8px rgba(0,0,0,0.3);
}

/* =========================
   RESET
   ========================= */
*, *::before, *::after { box-sizing: border-box; }

body {
  margin: 0;
  font-family: system-ui, -apple-system, BlinkMacSystemFont, sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
}

a { color: var(--primary); text-decoration: none; }
a:hover { text-decoration: underline; }

/* =========================
   NAV BAR
   ========================= */
.navbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.75rem 1.5rem;
  background: var(--nav-bg);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 100;
}

.navbar .logo {
  font-weight: 700;
  font-size: 1.1rem;
  color: var(--text);
}

.navbar .nav-links {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.navbar .nav-links a:not(.btn) {
  font-size: 0.9rem;
  color: var(--text-muted);
  padding: 0.25rem 0.65rem;
  border: 1px solid var(--border);
  border-radius: 999px;
  background: var(--bg);
  text-decoration: none;
  transition: color 0.2s, border-color 0.2s;
}

.navbar .nav-links a:not(.btn):hover {
  color: var(--text);
  border-color: var(--primary);
  text-decoration: none;
}

.theme-toggle {
  background: none;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.4rem 0.6rem;
  cursor: pointer;
  font-size: 1rem;
  color: var(--text);
}

.btn-logout {
  background: none;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.4rem 0.8rem;
  cursor: pointer;
  font-size: 0.85rem;
  color: var(--text-muted);
}

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

/* =========================
   UTILITY CLASSES
   ========================= */
.container {
  max-width: 800px;
  margin: 0 auto;
  padding: 2rem 1rem;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.65rem 1.25rem;
  font-size: 0.95rem;
  font-weight: 500;
  border: none;
  border-radius: var(--radius);
  cursor: pointer;
  transition: background 0.2s, transform 0.1s;
}

.btn:active { transform: scale(0.97); }

.btn-primary {
  background: var(--primary);
  color: var(--bg);
}

.btn-primary:hover { background: var(--primary-hover); }

.btn-danger {
  background: var(--danger);
  color: #fff;
}

.btn-danger:hover { background: var(--danger-hover); }

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

.btn-outline:hover { border-color: var(--text-muted); }

/* =========================
   FORMS
   ========================= */
.form-group {
  margin-bottom: 1rem;
}

.form-group label {
  display: block;
  font-size: 0.85rem;
  font-weight: 500;
  margin-bottom: 0.35rem;
  color: var(--text);
}

.form-group input,
.form-group select,
.form-group textarea {
  width: 100%;
  padding: 0.6rem 0.75rem;
  font-size: 0.95rem;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--input-bg);
  color: var(--text);
  outline: none;
  transition: border-color 0.2s;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
  border-color: var(--primary);
}

.form-group textarea {
  resize: vertical;
  min-height: 80px;
}

.form-error {
  color: var(--danger);
  font-size: 0.85rem;
  margin-top: 0.25rem;
}

.alert {
  padding: 0.75rem 1rem;
  border-radius: 8px;
  font-size: 0.9rem;
  margin-bottom: 1rem;
}

.alert-error {
  background: #fef2f2;
  color: #991b1b;
  border: 1px solid #fecaca;
}

.alert-success {
  background: #ecfdf5;
  color: #065f46;
  border: 1px solid #a7f3d0;
}

[data-theme="dark"] .alert-error {
  background: #451a1a;
  color: #fca5a5;
  border-color: #7f1d1d;
}

[data-theme="dark"] .alert-success {
  background: #064e3b;
  color: #6ee7b7;
  border-color: #065f46;
}

/* =========================
   MODAL
   ========================= */
.modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.5);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 200;
}

.modal {
  background: var(--bg-card);
  border-radius: var(--radius);
  padding: 1.5rem;
  max-width: 400px;
  width: 90%;
  box-shadow: var(--shadow);
}

.modal h3 { margin: 0 0 0.75rem; }

.modal-actions {
  display: flex;
  gap: 0.75rem;
  justify-content: flex-end;
  margin-top: 1.25rem;
}

/* =========================
   RESPONSIVE
   ========================= */
@media (max-width: 480px) {
  .navbar {
    padding: 0.6rem 1rem;
    flex-wrap: wrap;
    gap: 0.5rem;
  }
  .container { padding: 1rem 0.75rem; }
  .navbar .nav-links {
    gap: 0.4rem;
    flex-wrap: wrap;
    justify-content: flex-end;
  }
  .navbar .nav-links a:not(.btn) { font-size: 0.8rem; padding: 0.2rem 0.5rem; }
  .btn-logout { font-size: 0.75rem; padding: 0.3rem 0.6rem; }
  .theme-toggle { padding: 0.3rem 0.5rem; font-size: 0.85rem; }
  .btn { font-size: 0.85rem; padding: 0.55rem 1rem; }
}