/* ============================================================
   Cyber IQ - Dark Theme Stylesheet
   Theme: Maroon / Black / Dark Gray
   ============================================================ */

/* ----- CSS Variables ----- */
:root {
  --primary: #800020;
  --primary-dark: #5c0017;
  --primary-light: #a0002a;
  --primary-hover: #9a0028;
  --primary-glow: rgba(128, 0, 32, 0.4);
  --bg-dark: #0a0a0a;
  --bg-surface: #111111;
  --bg-card: #1a1a1a;
  --bg-card-hover: #222222;
  --bg-elevated: #242424;
  --bg-input: #1e1e1e;
  --text-primary: #e8e8e8;
  --text-secondary: #a0a0a0;
  --text-muted: #666666;
  --border-color: #2a2a2a;
  --border-light: #3a3a3a;
  --success: #00c853;
  --success-dark: #009624;
  --error: #ff1744;
  --error-dark: #c41230;
  --warning: #ffab00;
  --info: #2979ff;
  --easy: #00c853;
  --medium: #ffab00;
  --hard: #ff1744;
  --expert: #d500f9;
  --radius: 8px;
  --radius-lg: 12px;
  --radius-xl: 16px;
  --shadow: 0 2px 8px rgba(0,0,0,0.3);
  --shadow-lg: 0 8px 32px rgba(0,0,0,0.5);
  --transition: 0.2s ease;
  --font: 'Segoe UI', -apple-system, BlinkMacSystemFont, 'Roboto', sans-serif;
  --mono-font: 'Cascadia Code', 'Fira Code', 'Consolas', monospace;
}

/* ----- Reset & Base ----- */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

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

body {
  font-family: var(--font);
  background: var(--bg-dark);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--primary-light);
  text-decoration: none;
  transition: color var(--transition);
}
a:hover { color: #c0003a; }

img { max-width: 100%; display: block; }

ul { list-style: none; }

/* ----- Scrollbar ----- */
::-webkit-scrollbar { width: 8px; }
::-webkit-scrollbar-track { background: var(--bg-dark); }
::-webkit-scrollbar-thumb { background: #333; border-radius: 4px; }
::-webkit-scrollbar-thumb:hover { background: #555; }

/* ============================================================
   NAVIGATION
   ============================================================ */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: rgba(10, 10, 10, 0.95);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-color);
}

.nav-container {
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 1.4rem;
  font-weight: 700;
  color: var(--text-primary) !important;
}
.logo-icon { font-size: 1.6rem; }
.logo-accent { color: var(--primary-light); }

.nav-links {
  display: flex;
  align-items: center;
  gap: 8px;
}

.nav-link {
  color: var(--text-secondary) !important;
  padding: 8px 16px;
  border-radius: var(--radius);
  font-size: 0.9rem;
  font-weight: 500;
  transition: all var(--transition);
}
.nav-link:hover {
  color: var(--text-primary) !important;
  background: rgba(255,255,255,0.05);
}
.nav-link.active {
  color: var(--primary-light) !important;
  background: rgba(128,0,32,0.15);
}

.nav-auth { display: flex; align-items: center; gap: 8px; margin-left: 16px; }

.nav-user {
  display: flex;
  align-items: center;
  gap: 12px;
}
.nav-user .nav-link {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 6px 12px;
}

.user-avatar {
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background: var(--primary);
  color: white;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 0.85rem;
}

/* Hamburger */
.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
}
.nav-toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--text-primary);
  border-radius: 2px;
  transition: var(--transition);
}
.nav-toggle.active span:nth-child(1) { transform: rotate(45deg) translate(5px, 5px); }
.nav-toggle.active span:nth-child(2) { opacity: 0; }
.nav-toggle.active span:nth-child(3) { transform: rotate(-45deg) translate(5px, -5px); }

/* ============================================================
   BUTTONS
   ============================================================ */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 10px 24px;
  border: none;
  border-radius: var(--radius);
  font-family: var(--font);
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  transition: all var(--transition);
  text-decoration: none;
  white-space: nowrap;
}
.btn:disabled { opacity: 0.5; cursor: not-allowed; }

.btn-primary {
  background: var(--primary);
  color: white;
}
.btn-primary:hover:not(:disabled) {
  background: var(--primary-hover);
  box-shadow: 0 0 20px var(--primary-glow);
}

.btn-secondary {
  background: var(--bg-elevated);
  color: var(--text-primary);
  border: 1px solid var(--border-color);
}
.btn-secondary:hover:not(:disabled) {
  background: var(--bg-card-hover);
  border-color: var(--border-light);
}

.btn-outline {
  background: transparent;
  color: var(--text-secondary);
  border: 1px solid var(--border-color);
}
.btn-outline:hover:not(:disabled) {
  color: var(--text-primary);
  border-color: var(--text-muted);
}

.btn-ghost {
  background: transparent;
  color: var(--text-secondary);
}
.btn-ghost:hover:not(:disabled) {
  color: var(--text-primary);
  background: rgba(255,255,255,0.05);
}

.btn-success { background: var(--success-dark); color: white; }
.btn-danger { background: var(--error); color: white; }
.btn-danger:hover:not(:disabled) { background: var(--error-dark); }

.btn-sm { padding: 6px 14px; font-size: 0.82rem; }
.btn-lg { padding: 14px 32px; font-size: 1rem; }
.btn-full { width: 100%; }

.btn-icon {
  width: 40px;
  height: 40px;
  padding: 0;
  border-radius: 50%;
}

/* ============================================================
   FORM ELEMENTS
   ============================================================ */
.form-group {
  margin-bottom: 16px;
}
.form-group label {
  display: block;
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--text-secondary);
  margin-bottom: 6px;
}

.form-input,
.form-select,
.form-textarea {
  width: 100%;
  padding: 10px 14px;
  background: var(--bg-input);
  border: 1px solid var(--border-color);
  border-radius: var(--radius);
  color: var(--text-primary);
  font-family: var(--font);
  font-size: 0.9rem;
  transition: border-color var(--transition);
  outline: none;
}
.form-input:focus,
.form-select:focus,
.form-textarea:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px var(--primary-glow);
}
.form-input::placeholder { color: var(--text-muted); }
.form-textarea { resize: vertical; min-height: 100px; }
.form-select {
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath fill='%23666' d='M6 8L1 3h10z'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 12px center;
  padding-right: 36px;
}

.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}

/* ============================================================
   CARDS
   ============================================================ */
.card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 24px;
  transition: all var(--transition);
}
.card:hover {
  border-color: var(--border-light);
  box-shadow: var(--shadow);
}

.card-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 16px;
}

/* ============================================================
   BADGES
   ============================================================ */
.badge {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 4px 10px;
  border-radius: 20px;
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.badge-easy { background: rgba(0,200,83,0.15); color: var(--easy); }
.badge-medium { background: rgba(255,171,0,0.15); color: var(--medium); }
.badge-hard { background: rgba(255,23,68,0.15); color: var(--hard); }
.badge-expert { background: rgba(213,0,249,0.15); color: var(--expert); }

.badge-category {
  background: rgba(128,0,32,0.15);
  color: var(--primary-light);
}

/* ============================================================
   MODAL
   ============================================================ */
.modal-overlay {
  position: fixed;
  inset: 0;
  z-index: 2000;
  background: rgba(0,0,0,0.7);
  backdrop-filter: blur(4px);
  display: flex;
  align-items: center;
  justify-content: center;
  animation: fadeIn 0.2s ease;
}

.modal-content {
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-xl);
  padding: 32px;
  width: 90%;
  max-width: 440px;
  max-height: 90vh;
  overflow-y: auto;
  position: relative;
  animation: slideUp 0.3s ease;
}

.modal-close {
  position: absolute;
  top: 12px;
  right: 16px;
  background: none;
  border: none;
  color: var(--text-muted);
  font-size: 1.5rem;
  cursor: pointer;
  transition: color var(--transition);
}
.modal-close:hover { color: var(--text-primary); }

/* ----- Auth Modal ----- */
.auth-tabs {
  display: flex;
  border-bottom: 1px solid var(--border-color);
  margin-bottom: 24px;
}

.auth-tab {
  flex: 1;
  padding: 12px;
  background: none;
  border: none;
  color: var(--text-muted);
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  border-bottom: 2px solid transparent;
  transition: all var(--transition);
}
.auth-tab.active {
  color: var(--primary-light);
  border-bottom-color: var(--primary);
}

.auth-form { display: none; }
.auth-form.active { display: block; }

.auth-title {
  font-size: 1.4rem;
  margin-bottom: 4px;
}
.auth-subtitle {
  color: var(--text-muted);
  font-size: 0.9rem;
  margin-bottom: 24px;
}
.auth-error {
  color: var(--error);
  font-size: 0.85rem;
  margin-top: 12px;
  text-align: center;
}

/* ============================================================
   NOTIFICATION
   ============================================================ */
#notificationContainer {
  position: fixed;
  top: 80px;
  right: 24px;
  z-index: 3000;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.notification {
  padding: 14px 20px;
  border-radius: var(--radius);
  background: var(--bg-elevated);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  font-size: 0.9rem;
  box-shadow: var(--shadow-lg);
  animation: slideIn 0.3s ease;
  max-width: 380px;
  display: flex;
  align-items: center;
  gap: 10px;
}
.notification.success { border-left: 3px solid var(--success); }
.notification.error { border-left: 3px solid var(--error); }
.notification.warning { border-left: 3px solid var(--warning); }
.notification.info { border-left: 3px solid var(--info); }
.notification.removing { animation: slideOut 0.3s ease forwards; }

.notification-icon { font-size: 1.2rem; }

/* ============================================================
   MAIN CONTENT AREA
   ============================================================ */
#app {
  margin-top: 64px;
  min-height: calc(100vh - 64px);
}

.page {
  padding: 32px 24px;
  max-width: 1280px;
  margin: 0 auto;
}

.page-header {
  text-align: center;
  margin-bottom: 40px;
}
.page-header h1 {
  font-size: 2.2rem;
  margin-bottom: 8px;
}
.page-header p {
  color: var(--text-secondary);
  font-size: 1.05rem;
  max-width: 600px;
  margin: 0 auto;
}

.section-title {
  font-size: 1.3rem;
  margin-bottom: 20px;
  display: flex;
  align-items: center;
  gap: 10px;
}

/* ============================================================
   HOME PAGE
   ============================================================ */
.hero {
  min-height: calc(100vh - 64px);
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 40px 24px;
  background:
    radial-gradient(ellipse at 50% 0%, rgba(128,0,32,0.15) 0%, transparent 60%),
    radial-gradient(ellipse at 80% 80%, rgba(128,0,32,0.08) 0%, transparent 50%),
    var(--bg-dark);
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  top: -50%;
  left: -50%;
  width: 200%;
  height: 200%;
  background: repeating-linear-gradient(
    0deg,
    transparent,
    transparent 2px,
    rgba(128,0,32,0.02) 2px,
    rgba(128,0,32,0.02) 4px
  );
  pointer-events: none;
}

.hero-content {
  position: relative;
  z-index: 1;
  max-width: 800px;
}

.hero-badge {
  display: inline-block;
  padding: 8px 20px;
  border-radius: 20px;
  background: rgba(128,0,32,0.2);
  border: 1px solid rgba(128,0,32,0.3);
  color: var(--primary-light);
  font-size: 0.85rem;
  font-weight: 600;
  margin-bottom: 24px;
}

.hero h1 {
  font-size: 3.5rem;
  font-weight: 800;
  line-height: 1.1;
  margin-bottom: 16px;
}
.hero h1 .highlight {
  background: linear-gradient(135deg, var(--primary-light), #e04040);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero p {
  color: var(--text-secondary);
  font-size: 1.15rem;
  line-height: 1.7;
  margin-bottom: 32px;
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
}

.hero-actions {
  display: flex;
  gap: 12px;
  justify-content: center;
  flex-wrap: wrap;
}

/* Features Section */
.features {
  padding: 80px 24px;
  max-width: 1280px;
  margin: 0 auto;
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 24px;
  margin-top: 40px;
}

.feature-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 28px;
  text-align: center;
  transition: all var(--transition);
}
.feature-card:hover {
  border-color: var(--primary);
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(128,0,32,0.15);
}

.feature-icon {
  font-size: 2.5rem;
  margin-bottom: 16px;
}

.feature-card h3 {
  font-size: 1.1rem;
  margin-bottom: 8px;
}

.feature-card p {
  color: var(--text-secondary);
  font-size: 0.9rem;
  line-height: 1.6;
}

/* Stats Section */
.stats-section {
  padding: 60px 24px;
  background: var(--bg-surface);
  border-top: 1px solid var(--border-color);
  border-bottom: 1px solid var(--border-color);
}

.stats-grid {
  max-width: 1280px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 24px;
  text-align: center;
}

.stat-item h2 {
  font-size: 2.5rem;
  color: var(--primary-light);
  margin-bottom: 4px;
}

.stat-item p {
  color: var(--text-muted);
  font-size: 0.9rem;
  text-transform: uppercase;
  letter-spacing: 1px;
}

/* ============================================================
   CHALLENGES PAGE
   ============================================================ */
.challenge-type-tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-bottom: 8px;
}

.challenge-type-tab {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 10px 18px;
  border-radius: var(--radius-lg);
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  transition: all var(--transition);
}
.challenge-type-tab:hover {
  border-color: var(--text-muted);
  color: var(--text-primary);
}
.challenge-type-tab.active {
  background: rgba(128,0,32,0.2);
  border-color: var(--primary);
  color: var(--primary-light);
}
.challenge-type-tab-icon {
  font-size: 1.1rem;
}

.challenge-type-tagline {
  color: var(--text-muted);
  font-size: 0.85rem;
  margin-bottom: 24px;
}

.ctf-status-badge {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 3px 10px;
  border-radius: 20px;
  font-size: 0.72rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  margin-bottom: 10px;
}
.ctf-status-live { background: rgba(255,23,68,0.15); color: var(--hard); }
.ctf-status-upcoming { background: rgba(255,171,0,0.15); color: var(--medium); }
.ctf-status-ended { background: rgba(158,158,158,0.15); color: var(--text-muted); }

.challenge-card-timing {
  color: var(--text-muted);
  font-size: 0.78rem;
  margin-bottom: 12px;
}

/* ============================================================
   EVENTS
   ============================================================ */
.events-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 20px;
}

.event-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-top: 3px solid var(--event-color, var(--primary));
  border-radius: var(--radius-lg);
  padding: 20px;
  cursor: pointer;
  transition: all var(--transition);
}
.event-card:hover {
  border-color: var(--border-light);
  transform: translateY(-2px);
  box-shadow: var(--shadow);
}
.event-card-banner {
  font-size: 2.4rem;
  margin-bottom: 8px;
}

.event-banner {
  display: flex;
  align-items: center;
  gap: 24px;
  padding: 32px;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-top: 4px solid var(--event-color, var(--primary));
  border-radius: var(--radius-xl);
  margin-bottom: 24px;
}
.event-banner-icon {
  font-size: 3.5rem;
  flex-shrink: 0;
}
.event-banner h1 {
  margin-bottom: 6px;
}
.event-countdown {
  margin-top: 10px;
  font-family: var(--mono-font);
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--event-color, var(--primary-light));
}

.event-prize-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 8px;
}
.event-prize-list li {
  padding: 10px 14px;
  background: rgba(255,171,0,0.08);
  border: 1px solid rgba(255,171,0,0.2);
  border-radius: var(--radius);
  font-weight: 600;
}

.event-sponsors {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}
.event-sponsor-chip {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 16px;
  background: var(--bg-dark);
  border: 1px solid var(--border-color);
  border-radius: 20px;
  color: var(--text-primary);
  font-weight: 600;
  font-size: 0.85rem;
  transition: all var(--transition);
}
a.event-sponsor-chip:hover {
  border-color: var(--primary);
  color: var(--primary-light);
}

/* ============================================================
   COURSES
   ============================================================ */
.course-progress-bar {
  width: 100%;
  height: 6px;
  border-radius: 4px;
  background: var(--border-color);
  overflow: hidden;
  margin-bottom: 8px;
}
.course-progress-fill {
  height: 100%;
  background: var(--primary);
  transition: width var(--transition);
}

.course-detail-body {
  display: grid;
  grid-template-columns: 260px 1fr;
  gap: 24px;
  align-items: start;
}

.course-lessons-sidebar {
  display: flex;
  flex-direction: column;
  gap: 6px;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 12px;
  position: sticky;
  top: 88px;
}

.course-lesson-item {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 10px 12px;
  border-radius: var(--radius);
  background: transparent;
  border: none;
  color: var(--text-secondary);
  text-align: left;
  font-size: 0.85rem;
  cursor: pointer;
  transition: all var(--transition);
}
.course-lesson-item:hover {
  background: rgba(255,255,255,0.04);
  color: var(--text-primary);
}
.course-lesson-item.active {
  background: rgba(128,0,32,0.2);
  color: var(--primary-light);
}

.course-lesson-status {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 22px;
  height: 22px;
  border-radius: 50%;
  background: var(--bg-dark);
  border: 1px solid var(--border-color);
  font-size: 0.72rem;
  font-weight: 700;
  flex-shrink: 0;
}

.course-lesson-content {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 28px;
}

@media (max-width: 768px) {
  .course-detail-body {
    grid-template-columns: 1fr;
  }
  .course-lessons-sidebar {
    position: static;
  }
}

.challenges-header {
  display: flex;
  flex-direction: column;
  gap: 20px;
  margin-bottom: 32px;
}

.challenges-filters {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  align-items: center;
}

.filter-categories {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.filter-btn {
  padding: 6px 16px;
  border-radius: 20px;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  font-size: 0.82rem;
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition);
}
.filter-btn:hover {
  border-color: var(--text-muted);
  color: var(--text-primary);
}
.filter-btn.active {
  background: rgba(128,0,32,0.2);
  border-color: var(--primary);
  color: var(--primary-light);
}

.filter-difficulty {
  display: flex;
  gap: 6px;
}

.filter-diff-btn {
  padding: 6px 14px;
  border-radius: 20px;
  background: transparent;
  border: 1px solid var(--border-color);
  color: var(--text-muted);
  font-size: 0.78rem;
  font-weight: 600;
  text-transform: uppercase;
  cursor: pointer;
  transition: all var(--transition);
}
.filter-diff-btn:hover { color: var(--text-secondary); }
.filter-diff-btn.active { border-color: currentColor; }
.filter-diff-btn[data-diff="easy"].active { color: var(--easy); }
.filter-diff-btn[data-diff="medium"].active { color: var(--medium); }
.filter-diff-btn[data-diff="hard"].active { color: var(--hard); }
.filter-diff-btn[data-diff="expert"].active { color: var(--expert); }

.challenges-search {
  flex: 1;
  min-width: 200px;
  max-width: 320px;
}

.challenges-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 20px;
}

.challenge-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 20px;
  cursor: pointer;
  transition: all var(--transition);
  position: relative;
  overflow: hidden;
}
.challenge-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 3px;
  height: 100%;
  background: var(--primary);
  opacity: 0;
  transition: opacity var(--transition);
}
.challenge-card:hover {
  border-color: var(--border-light);
  transform: translateY(-2px);
  box-shadow: var(--shadow);
}
.challenge-card:hover::before { opacity: 1; }

.challenge-card.solved {
  border-color: rgba(0,200,83,0.3);
}
.challenge-card.solved::before {
  background: var(--success);
  opacity: 1;
}

.challenge-card-top {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  margin-bottom: 12px;
}

.challenge-card-category {
  font-size: 0.78rem;
  color: var(--text-muted);
  display: flex;
  align-items: center;
  gap: 6px;
}

.challenge-card-points {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--primary-light);
}

.challenge-card h3 {
  font-size: 1.05rem;
  margin-bottom: 8px;
}

.challenge-card-desc {
  color: var(--text-muted);
  font-size: 0.85rem;
  line-height: 1.5;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
  margin-bottom: 12px;
}

.challenge-card-footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-top: 12px;
  border-top: 1px solid var(--border-color);
}

.challenge-card-solves {
  color: var(--text-muted);
  font-size: 0.8rem;
  display: flex;
  align-items: center;
  gap: 4px;
}

/* ============================================================
   CHALLENGE DETAIL PAGE
   ============================================================ */
.challenge-detail {
  max-width: 900px;
  margin: 0 auto;
}

.challenge-detail-header {
  margin-bottom: 24px;
}

.challenge-detail-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  align-items: center;
  margin: 12px 0;
}

.challenge-detail-points {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--primary-light);
}

.challenge-detail-body {
  display: grid;
  grid-template-columns: 1fr 320px;
  gap: 24px;
}

.challenge-description {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 24px;
  line-height: 1.8;
  font-size: 0.95rem;
}

.challenge-description pre,
.challenge-description code {
  font-family: var(--mono-font);
  background: var(--bg-input);
  border-radius: 4px;
}
.challenge-description code { padding: 2px 6px; font-size: 0.9em; }
.challenge-description pre {
  padding: 16px;
  overflow-x: auto;
  margin: 16px 0;
  border: 1px solid var(--border-color);
}
.challenge-description pre code { background: none; padding: 0; }

.challenge-sidebar {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.flag-submit-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 20px;
}

.flag-submit-card h3 {
  font-size: 1rem;
  margin-bottom: 12px;
}

.flag-input-group {
  display: flex;
  gap: 8px;
}
.flag-input-group .form-input {
  font-family: var(--mono-font);
  font-size: 0.85rem;
}

.challenge-status {
  padding: 12px 16px;
  border-radius: var(--radius);
  font-size: 0.9rem;
  font-weight: 600;
}
.challenge-status.solved {
  background: rgba(0,200,83,0.1);
  color: var(--success);
  border: 1px solid rgba(0,200,83,0.2);
}
.challenge-status.unsolved {
  background: rgba(255,23,68,0.1);
  color: var(--error);
  border: 1px solid rgba(255,23,68,0.2);
}

.challenge-external-link {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 12px 16px;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius);
  color: var(--text-primary);
  transition: all var(--transition);
}
.challenge-external-link:hover {
  border-color: var(--primary);
  color: var(--primary-light);
}

.lab-launch-btn {
  background: var(--primary);
  border-color: var(--primary);
  color: white;
  font-weight: 700;
  justify-content: center;
  margin-bottom: 4px;
}
.lab-launch-btn:hover {
  background: var(--primary-light);
  border-color: var(--primary-light);
  color: white;
}

.lab-badge {
  font-size: 0.75em;
  vertical-align: middle;
}

/* ============================================================
   LEADERBOARD
   ============================================================ */
.leaderboard-toggle {
  display: flex;
  gap: 0;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius);
  overflow: hidden;
  width: fit-content;
  margin-bottom: 24px;
}

.lb-toggle-btn {
  padding: 10px 24px;
  background: none;
  border: none;
  color: var(--text-muted);
  font-weight: 600;
  cursor: pointer;
  transition: all var(--transition);
}
.lb-toggle-btn.active {
  background: var(--primary);
  color: white;
}
.lb-toggle-btn:not(.active):hover {
  color: var(--text-primary);
}

.leaderboard-table {
  width: 100%;
  border-collapse: collapse;
  background: var(--bg-card);
  border-radius: var(--radius-lg);
  overflow: hidden;
  border: 1px solid var(--border-color);
}

.leaderboard-table th {
  background: var(--bg-surface);
  padding: 14px 16px;
  text-align: left;
  font-size: 0.82rem;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  color: var(--text-muted);
  font-weight: 600;
  border-bottom: 1px solid var(--border-color);
}

.leaderboard-table td {
  padding: 14px 16px;
  border-bottom: 1px solid var(--border-color);
  font-size: 0.9rem;
}

.leaderboard-table tr:last-child td { border-bottom: none; }
.leaderboard-table tr:hover { background: rgba(255,255,255,0.02); }

.lb-rank {
  font-weight: 700;
  font-size: 1.1rem;
  width: 48px;
  text-align: center;
}
.lb-rank.gold { color: #ffd700; }
.lb-rank.silver { color: #c0c0c0; }
.lb-rank.bronze { color: #cd7f32; }

.lb-user {
  display: flex;
  align-items: center;
  gap: 10px;
}
.lb-avatar {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: var(--primary);
  color: white;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 0.85rem;
}

.lb-points {
  font-weight: 700;
  color: var(--primary-light);
}

.lb-solved {
  color: var(--success);
}

.lb-time {
  color: var(--text-muted);
  font-size: 0.82rem;
}

/* ============================================================
   PROFILE PAGE
   ============================================================ */
.profile-header {
  display: flex;
  align-items: center;
  gap: 24px;
  padding: 32px;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-xl);
  margin-bottom: 32px;
}

.profile-avatar {
  width: 80px;
  height: 80px;
  border-radius: 50%;
  background: var(--primary);
  color: white;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 2rem;
  font-weight: 700;
  flex-shrink: 0;
}

.profile-info h2 {
  font-size: 1.5rem;
  margin-bottom: 4px;
}
.profile-info .profile-meta {
  color: var(--text-muted);
  font-size: 0.9rem;
}

.profile-stats {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
  gap: 16px;
  margin-bottom: 32px;
}

.profile-stat {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius);
  padding: 20px;
  text-align: center;
}
.profile-stat .stat-value {
  font-size: 1.6rem;
  font-weight: 700;
  color: var(--primary-light);
}
.profile-stat .stat-label {
  color: var(--text-muted);
  font-size: 0.82rem;
  margin-top: 4px;
}

.profile-solved h3 {
  margin-bottom: 16px;
}

/* ============================================================
   GAMIFICATION (ranks + badges)
   ============================================================ */
.rank-badge {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 3px 10px;
  border-radius: 20px;
  background: rgba(128,0,32,0.15);
  color: var(--primary-light);
  font-size: 0.78rem;
  font-weight: 600;
  white-space: nowrap;
}

.badges-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(110px, 1fr));
  gap: 14px;
}

.badge-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 16px 10px;
  text-align: center;
  transition: all var(--transition);
}
.badge-card.earned {
  border-color: rgba(255,171,0,0.4);
  background: rgba(255,171,0,0.06);
}
.badge-card.locked {
  opacity: 0.45;
}
.badge-card-icon {
  font-size: 1.8rem;
  margin-bottom: 6px;
}
.badge-card-name {
  font-size: 0.75rem;
  color: var(--text-secondary);
  font-weight: 600;
}

/* ============================================================
   ADMIN PAGE
   ============================================================ */
.admin-layout {
  display: grid;
  grid-template-columns: 220px 1fr;
  gap: 24px;
  min-height: calc(100vh - 64px - 64px);
}

.admin-sidebar {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 16px;
  position: sticky;
  top: 80px;
  height: fit-content;
}

.admin-nav-item {
  display: block;
  width: 100%;
  padding: 10px 16px;
  background: none;
  border: none;
  color: var(--text-secondary);
  font-size: 0.9rem;
  text-align: left;
  cursor: pointer;
  border-radius: var(--radius);
  transition: all var(--transition);
}
.admin-nav-item:hover {
  color: var(--text-primary);
  background: rgba(255,255,255,0.05);
}
.admin-nav-item.active {
  color: var(--primary-light);
  background: rgba(128,0,32,0.15);
}

.admin-content {
  min-height: 400px;
}

.admin-table {
  width: 100%;
  border-collapse: collapse;
  background: var(--bg-card);
  border-radius: var(--radius-lg);
  overflow: hidden;
  border: 1px solid var(--border-color);
}

.admin-table th {
  background: var(--bg-surface);
  padding: 12px 16px;
  text-align: left;
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  color: var(--text-muted);
  border-bottom: 1px solid var(--border-color);
}

.admin-table td {
  padding: 12px 16px;
  border-bottom: 1px solid var(--border-color);
  font-size: 0.88rem;
}

.admin-table tr:last-child td { border-bottom: none; }
.admin-table tr:hover { background: rgba(255,255,255,0.02); }

/* ============================================================
   LOADING
   ============================================================ */
.loading-container {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 80px 24px;
  color: var(--text-muted);
}

.loading-spinner {
  width: 40px;
  height: 40px;
  border: 3px solid var(--border-color);
  border-top-color: var(--primary-light);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
  margin-bottom: 16px;
}

/* ============================================================
   EMPTY STATE
   ============================================================ */
.empty-state {
  text-align: center;
  padding: 60px 24px;
  color: var(--text-muted);
}
.empty-state .empty-icon { font-size: 3rem; margin-bottom: 16px; }
.empty-state h3 { color: var(--text-secondary); margin-bottom: 8px; }

/* ============================================================
   UTILITY
   ============================================================ */
.text-center { text-align: center; }
.text-muted { color: var(--text-muted); }
.mt-8 { margin-top: 8px; }
.mt-16 { margin-top: 16px; }
.mt-24 { margin-top: 24px; }
.mt-32 { margin-top: 32px; }
.mb-16 { margin-bottom: 16px; }
.mb-24 { margin-bottom: 24px; }
.gap-8 { gap: 8px; }
.gap-12 { gap: 12px; }
.flex { display: flex; }
.flex-wrap { flex-wrap: wrap; }
.items-center { align-items: center; }
.justify-between { justify-content: space-between; }
.hidden { display: none !important; }

/* ============================================================
   ANIMATIONS
   ============================================================ */
@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

@keyframes slideUp {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}

@keyframes slideIn {
  from { opacity: 0; transform: translateX(100px); }
  to { opacity: 1; transform: translateX(0); }
}

@keyframes slideOut {
  from { opacity: 1; transform: translateX(0); }
  to { opacity: 0; transform: translateX(100px); }
}

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

@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.5; }
}

/* ============================================================
   RESPONSIVE DESIGN
   ============================================================ */

/* Tablet */
@media (max-width: 1024px) {
  .challenge-detail-body {
    grid-template-columns: 1fr;
  }
  .admin-layout {
    grid-template-columns: 1fr;
  }
  .admin-sidebar {
    position: static;
    display: flex;
    flex-wrap: wrap;
    gap: 4px;
  }
  .admin-nav-item {
    width: auto;
  }
}

/* Mobile */
@media (max-width: 768px) {
  .nav-toggle { display: flex; }

  .nav-links {
    position: absolute;
    top: 64px;
    left: 0;
    right: 0;
    background: rgba(10,10,10,0.98);
    flex-direction: column;
    padding: 16px 24px;
    gap: 4px;
    border-bottom: 1px solid var(--border-color);
    display: none;
  }
  .nav-links.open { display: flex; }
  .nav-auth { margin-left: 0; width: 100%; }
  .nav-auth .btn { flex: 1; }
  .nav-user { width: 100%; justify-content: space-between; }

  .hero h1 { font-size: 2rem; }
  .hero p { font-size: 1rem; }

  .page { padding: 24px 16px; }

  .page-header h1 { font-size: 1.6rem; }

  .challenges-grid {
    grid-template-columns: 1fr;
  }

  .challenges-filters {
    flex-direction: column;
    align-items: stretch;
  }
  .challenges-search { max-width: none; }

  .form-row { grid-template-columns: 1fr; }

  .profile-header {
    flex-direction: column;
    text-align: center;
  }

  .leaderboard-table { font-size: 0.85rem; }
  .leaderboard-table th, .leaderboard-table td { padding: 10px 12px; }
  .lb-time { display: none; }

  .modal-content { padding: 24px; }

  .stats-grid { grid-template-columns: repeat(2, 1fr); }

  .features-grid { grid-template-columns: 1fr; }
}

/* Small Mobile */
@media (max-width: 480px) {
  .hero h1 { font-size: 1.6rem; }
  .hero-actions { flex-direction: column; }
  .hero-actions .btn { width: 100%; }

  .challenge-detail-meta { gap: 8px; }
  .flag-input-group { flex-direction: column; }

  .leaderboard-table th:nth-child(4),
  .leaderboard-table td:nth-child(4) { display: none; }

  .stats-grid { grid-template-columns: 1fr 1fr; gap: 16px; }
  .stat-item h2 { font-size: 1.8rem; }
}