/* ============================================================
   style.css — Central Stylesheet for AP CS Student Testing Platform
   Palette: Navy Blue (#0D1B2A), Slate Grey (#6B7C93), White (#FFFFFF)
   Accent:  Gold (#C9A84C) for high-stakes emphasis
   ============================================================ */

/* ── 1. DESIGN TOKENS (CSS Variables) ─────────────────────── */
:root {
  /* Colors */
  --navy:        #0D1B2A;
  --navy-mid:    #1A2E45;
  --navy-light:  #243B55;
  --slate:       #6B7C93;
  --slate-light: #A0AEBF;
  --white:       #FFFFFF;
  --off-white:   #F4F6F9;
  --accent:      #C9A84C;   /* gold — used sparingly for urgency/highlights */
  --danger:      #C0392B;
  --success:     #1E7E34;
  --border:      #D1D9E0;

  /* Typography */
  --font-display: 'DM Serif Display', Georgia, serif;
  --font-body:    'IBM Plex Sans', 'Segoe UI', sans-serif;
  --font-mono:    'IBM Plex Mono', 'Courier New', monospace;

  /* Spacing */
  --radius:    6px;
  --radius-lg: 12px;
  --shadow-sm: 0 1px 4px rgba(0,0,0,0.08);
  --shadow-md: 0 4px 16px rgba(0,0,0,0.12);
  --shadow-lg: 0 8px 32px rgba(0,0,0,0.18);

  /* Transitions */
  --ease: cubic-bezier(0.25, 0.8, 0.25, 1);
}

/* ── 2. RESET & BASE ───────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html { font-size: 16px; scroll-behavior: smooth; }

body {
  font-family: var(--font-body);
  background-color: var(--off-white);
  color: var(--navy);
  line-height: 1.6;
  min-height: 100vh;
}

/* Import Google Fonts */
@import url('https://fonts.googleapis.com/css2?family=DM+Serif+Display&family=IBM+Plex+Sans:wght@300;400;500;600&family=IBM+Plex+Mono:wght@400;500&display=swap');

/* ── 3. TYPOGRAPHY ─────────────────────────────────────────── */
h1, h2, h3 { font-family: var(--font-display); color: var(--navy); line-height: 1.2; }
h1 { font-size: clamp(1.8rem, 4vw, 2.8rem); }
h2 { font-size: clamp(1.3rem, 2.5vw, 1.9rem); }
h3 { font-size: 1.15rem; }
p  { color: var(--slate); font-size: 0.95rem; }
a  { color: var(--navy-light); text-decoration: none; transition: color 0.2s; }
a:hover { color: var(--accent); }

/* ── 4. LAYOUT UTILITIES ───────────────────────────────────── */
.container   { max-width: 1100px; margin: 0 auto; padding: 0 24px; }
.flex        { display: flex; }
.flex-center { display: flex; align-items: center; justify-content: center; }
.gap-sm      { gap: 8px; }
.gap-md      { gap: 16px; }
.gap-lg      { gap: 24px; }

/* ── 5. HEADER / NAVBAR ────────────────────────────────────── */
.site-header {
  background: var(--navy);
  border-bottom: 2px solid var(--accent);
  padding: 0 32px;
  height: 60px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: var(--shadow-md);
}

.site-header .logo {
  font-family: var(--font-display);
  color: var(--white);
  font-size: 1.2rem;
  letter-spacing: 0.5px;
}

.site-header .logo span { color: var(--accent); }

.site-header nav a {
  color: var(--slate-light);
  font-size: 0.85rem;
  font-weight: 500;
  letter-spacing: 0.5px;
  text-transform: uppercase;
  padding: 6px 12px;
  border-radius: var(--radius);
  transition: all 0.2s var(--ease);
}

.site-header nav a:hover,
.site-header nav a.active {
  color: var(--white);
  background: var(--navy-light);
}

.site-header .user-badge {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--slate-light);
  font-size: 0.85rem;
}

.site-header .user-badge .avatar {
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background: var(--navy-light);
  border: 2px solid var(--slate);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--white);
  font-size: 0.75rem;
  font-weight: 600;
  object-fit: cover;
}

/* ── 6. BUTTONS ────────────────────────────────────────────── */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 10px 22px;
  border: none;
  border-radius: var(--radius);
  font-family: var(--font-body);
  font-size: 0.9rem;
  font-weight: 600;
  letter-spacing: 0.3px;
  cursor: pointer;
  transition: all 0.2s var(--ease);
}

.btn-primary {
  background: var(--navy);
  color: var(--white);
  box-shadow: var(--shadow-sm);
}
.btn-primary:hover { background: var(--navy-light); transform: translateY(-1px); box-shadow: var(--shadow-md); }

.btn-accent {
  background: var(--accent);
  color: var(--navy);
}
.btn-accent:hover { filter: brightness(1.08); transform: translateY(-1px); }

.btn-outline {
  background: transparent;
  color: var(--navy);
  border: 1.5px solid var(--border);
}
.btn-outline:hover { border-color: var(--navy); background: var(--off-white); }

.btn-danger { background: var(--danger); color: var(--white); }
.btn-danger:hover { filter: brightness(0.9); }

.btn-lg  { padding: 13px 30px; font-size: 1rem; }
.btn-sm  { padding: 7px 14px; font-size: 0.8rem; }
.btn:disabled { opacity: 0.5; cursor: not-allowed; transform: none !important; }

/* ── 7. FORM ELEMENTS ──────────────────────────────────────── */
.form-group { display: flex; flex-direction: column; gap: 6px; }

.form-group label {
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--navy);
  text-transform: uppercase;
  letter-spacing: 0.6px;
}

.form-group input,
.form-group select {
  padding: 10px 14px;
  border: 1.5px solid var(--border);
  border-radius: var(--radius);
  font-family: var(--font-body);
  font-size: 0.95rem;
  color: var(--navy);
  background: var(--white);
  transition: border-color 0.2s, box-shadow 0.2s;
  outline: none;
}

.form-group input:focus,
.form-group select:focus {
  border-color: var(--navy);
  box-shadow: 0 0 0 3px rgba(13, 27, 42, 0.1);
}

/* ── 8. CARDS ──────────────────────────────────────────────── */
.card {
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 28px;
  box-shadow: var(--shadow-sm);
  transition: box-shadow 0.2s var(--ease), transform 0.2s var(--ease);
}

.card:hover { box-shadow: var(--shadow-md); }

.card-header {
  border-bottom: 1px solid var(--border);
  padding-bottom: 16px;
  margin-bottom: 20px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

/* ── 9. BADGES & STATUS TAGS ───────────────────────────────── */
.badge {
  display: inline-block;
  padding: 3px 10px;
  border-radius: 99px;
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.4px;
  text-transform: uppercase;
}
.badge-navy    { background: var(--navy);    color: var(--white); }
.badge-slate   { background: var(--slate-light); color: var(--navy); }
.badge-accent  { background: var(--accent);  color: var(--navy); }
.badge-success { background: #d4edda; color: var(--success); }
.badge-danger  { background: #f8d7da; color: var(--danger); }

/* ── 10. ALERTS / BANNERS ──────────────────────────────────── */
.alert {
  padding: 12px 18px;
  border-radius: var(--radius);
  font-size: 0.88rem;
  border-left: 4px solid;
}
.alert-info    { background: #e8edf5; border-color: var(--navy); color: var(--navy-mid); }
.alert-warning { background: #fef9e7; border-color: var(--accent); color: #7d6009; }
.alert-danger  { background: #fde8e8; border-color: var(--danger); color: var(--danger); }

/* ── 11. PROGRESS BAR ──────────────────────────────────────── */
.progress-bar-track {
  background: var(--border);
  border-radius: 99px;
  height: 6px;
  overflow: hidden;
}
.progress-bar-fill {
  height: 100%;
  background: var(--navy);
  border-radius: 99px;
  transition: width 0.4s var(--ease);
}
.progress-bar-fill.accent { background: var(--accent); }

/* ── 12. DIVIDER ───────────────────────────────────────────── */
.divider {
  border: none;
  border-top: 1px solid var(--border);
  margin: 20px 0;
}

/* ── 13. FOOTER ────────────────────────────────────────────── */
.site-footer {
  background: var(--navy);
  color: var(--slate-light);
  text-align: center;
  padding: 20px;
  font-size: 0.78rem;
  margin-top: auto;
  border-top: 2px solid var(--accent);
}

/* ── 14. MODALS ────────────────────────────────────────────── */
.modal-overlay {
  position: fixed; inset: 0;
  background: rgba(13, 27, 42, 0.65);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1000;
  backdrop-filter: blur(3px);
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.25s;
}
.modal-overlay.open { opacity: 1; pointer-events: all; }

.modal {
  background: var(--white);
  border-radius: var(--radius-lg);
  padding: 36px;
  max-width: 480px;
  width: 90%;
  box-shadow: var(--shadow-lg);
  transform: translateY(20px);
  transition: transform 0.25s var(--ease);
}
.modal-overlay.open .modal { transform: translateY(0); }

/* ── 15. LOADING SPINNER ───────────────────────────────────── */
.spinner {
  width: 22px; height: 22px;
  border: 3px solid var(--border);
  border-top-color: var(--navy);
  border-radius: 50%;
  animation: spin 0.7s linear infinite;
  display: inline-block;
}
@keyframes spin { to { transform: rotate(360deg); } }

/* ── 16. RESPONSIVE UTILITIES ──────────────────────────────── */
@media (max-width: 768px) {
  .hide-mobile { display: none !important; }
  .site-header { padding: 0 16px; }
  .container   { padding: 0 16px; }
}