/* =====================================================
   Digital Learning — Global Design System
   Editorial Luxury: Dark navy + warm cream + serif display
   ===================================================== */

/* ─── CSS Variables — Editorial Luxury Palette ─────── */
:root {
  --color-navy:       #1B2B4B;
  --color-navy-light: #2A3F5F;
  --color-navy-dark:  #0A1628;
  --color-white:      #FFFFFF;
  --color-gold:       #C5A55A;
  --color-gold-hover: #B8972F;
  --color-gold-light: #D4C089;
  --color-cream:      #FAF7F2;
  --color-cream-dark: #F0EBE3;
  --color-teal:       #1B2B4B;
  --color-teal-hover: #0A1628;

  --color-gray-50:  #FDFCFA;
  --color-gray-100: #F5F2ED;
  --color-gray-200: #E8E4DD;
  --color-gray-300: #D1CCC3;
  --color-gray-400: #9E9890;
  --color-gray-500: #6E6862;
  --color-gray-600: #524C46;
  --color-gray-700: #3A3530;
  --color-gray-800: #1F1B17;
  --color-gray-900: #141210;

  --color-success: #2D6A4F;
  --color-error:   #C1292E;
  --color-warning: #E8A317;
  --color-info:    #1B2B4B;

  --font-display: 'Poppins', 'Segoe UI', Roboto, 'Helvetica Neue', sans-serif;
  --font-primary: 'Source Sans 3', 'Segoe UI', Roboto, 'Helvetica Neue', sans-serif;
  --font-mono:    'JetBrains Mono', 'Fira Code', monospace;

  --fs-xs:   0.8125rem;
  --fs-sm:   0.9375rem;
  --fs-base: 1rem;
  --fs-md:   1.125rem;
  --fs-lg:   1.25rem;
  --fs-xl:   1.5rem;
  --fs-2xl:  1.875rem;
  --fs-3xl:  2.25rem;
  --fs-4xl:  3rem;
  --fs-5xl:  3.75rem;

  --fw-light:     300;
  --fw-normal:    400;
  --fw-medium:    500;
  --fw-semibold:  600;
  --fw-bold:      700;
  --fw-extrabold: 800;

  --space-1:  0.25rem;
  --space-2:  0.5rem;
  --space-3:  0.75rem;
  --space-4:  1rem;
  --space-5:  1.25rem;
  --space-6:  1.5rem;
  --space-8:  2rem;
  --space-10: 2.5rem;
  --space-12: 3rem;
  --space-16: 4rem;
  --space-20: 5rem;
  --space-24: 6rem;

  --max-width:     1200px;
  --sidebar-width: 260px;
  --navbar-height: 72px;

  --radius-sm:   3px;
  --radius-md:   5px;
  --radius-lg:   8px;
  --radius-xl:   12px;
  --radius-full: 9999px;

  --shadow-sm: 0 1px 2px rgba(20,18,16,0.04);
  --shadow-md: 0 2px 8px rgba(20,18,16,0.06), 0 1px 2px rgba(20,18,16,0.04);
  --shadow-lg: 0 8px 24px rgba(20,18,16,0.08), 0 2px 6px rgba(20,18,16,0.04);
  --shadow-xl: 0 16px 40px rgba(20,18,16,0.10), 0 4px 12px rgba(20,18,16,0.06);

  --transition-fast:   150ms ease;
  --transition-normal: 250ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow:   400ms cubic-bezier(0.4, 0, 0.2, 1);
}

/* ─── CSS Reset ─────────────────────────────────────── */
*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }
html { font-size: 16px; scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body {
  font-family: var(--font-primary);
  font-size: var(--fs-base);
  font-weight: var(--fw-normal);
  line-height: 1.7;
  color: var(--color-gray-800);
  background-color: var(--color-cream);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  letter-spacing: 0.01em;
}
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-display);
  font-weight: var(--fw-bold);
  line-height: 1.2;
  letter-spacing: -0.01em;
  color: var(--color-gray-900);
}
img, picture, video, canvas, svg { display: block; max-width: 100%; }
input, button, textarea, select { font: inherit; color: inherit; }
a { text-decoration: none; color: inherit; }
ul, ol { list-style: none; }
button { cursor: pointer; border: none; background: none; }

/* ─── Utility ───────────────────────────────────────── */
.container { width: 100%; max-width: var(--max-width); margin: 0 auto; padding: 0 var(--space-6); }
.sr-only { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0,0,0,0); white-space: nowrap; border: 0; }

/* ─── Buttons ───────────────────────────────────────── */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: var(--space-2);
  padding: 11px 28px; font-family: var(--font-primary); font-size: var(--fs-sm);
  font-weight: var(--fw-semibold); line-height: 1.2; border-radius: var(--radius-sm);
  transition: all var(--transition-fast); white-space: nowrap;
  letter-spacing: 0.04em; text-transform: uppercase; border: 2px solid transparent;
}
.btn-primary { background: var(--color-navy); color: var(--color-white); border-color: var(--color-navy); }
.btn-primary:hover { background: var(--color-navy-dark); border-color: var(--color-navy-dark); }
.btn-secondary { background: transparent; color: var(--color-navy); border-color: var(--color-navy); }
.btn-secondary:hover { background: var(--color-navy); color: var(--color-white); }
.btn-outline { border: 2px solid var(--color-gray-800); color: var(--color-gray-800); background: transparent; }
.btn-outline:hover { background: var(--color-gray-800); color: var(--color-white); }
.btn-gold { background: var(--color-gold); color: var(--color-navy-dark); border-color: var(--color-gold); font-weight: var(--fw-bold); }
.btn-gold:hover { background: var(--color-gold-hover); border-color: var(--color-gold-hover); }
.btn-danger { background: var(--color-error); color: var(--color-white); border-color: var(--color-error); }
.btn-danger:hover { background: #a32124; border-color: #a32124; }
.btn-sm { padding: 7px 18px; font-size: var(--fs-xs); }
.btn-lg { padding: 14px 36px; font-size: var(--fs-base); }
.btn-block { width: 100%; }

/* ─── Forms ─────────────────────────────────────────── */
.form-group { margin-bottom: var(--space-5); }
.form-label {
  display: block; margin-bottom: var(--space-2); font-size: var(--fs-sm);
  font-weight: var(--fw-semibold); color: var(--color-gray-700);
  letter-spacing: 0.02em;
}
.form-input, .form-select, .form-textarea {
  width: 100%; padding: 11px 16px; font-size: var(--fs-base);
  border: 1px solid var(--color-gray-300); border-radius: var(--radius-sm);
  background: var(--color-white); color: var(--color-gray-800);
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}
.form-input:focus, .form-select:focus, .form-textarea:focus {
  outline: none; border-color: var(--color-navy); box-shadow: 0 0 0 3px rgba(27,43,75,0.08);
}
.form-input::placeholder { color: var(--color-gray-400); }
.form-input.error { border-color: var(--color-error); }
.form-textarea { resize: vertical; min-height: 120px; }

/* ─── Cards ─────────────────────────────────────────── */
.card {
  background: var(--color-white); border-radius: var(--radius-md);
  border: 1px solid var(--color-gray-200); overflow: hidden;
  transition: border-color var(--transition-normal), box-shadow var(--transition-normal);
}
.card:hover { border-color: var(--color-gray-300); box-shadow: var(--shadow-md); }

/* ─── Badges ────────────────────────────────────────── */
.badge {
  display: inline-flex; align-items: center; padding: 3px 10px;
  font-size: var(--fs-xs); font-weight: var(--fw-bold);
  border-radius: var(--radius-sm); letter-spacing: 0.03em; text-transform: uppercase;
}
.badge-success { background: rgba(25,135,84,0.1); color: #155724; }
.badge-warning { background: rgba(197,165,90,0.15); color: #7a5e1e; }
.badge-error   { background: rgba(220,53,69,0.1); color: #721c24; }
.badge-info    { background: rgba(27,43,75,0.1); color: #1B2B4B; }

/* ─── Alerts ────────────────────────────────────────── */
.alert {
  padding: 14px 20px; border-radius: var(--radius-md); font-size: var(--fs-sm);
  font-weight: var(--fw-medium); margin-bottom: var(--space-5);
  border-left: 4px solid transparent;
}
.alert-success { background: #d4edda; color: #155724; border-left-color: var(--color-success); }
.alert-error   { background: #f8d7da; color: #721c24; border-left-color: var(--color-error); }
.alert-warning { background: #fef3cd; color: #856404; border-left-color: var(--color-warning); }
.alert-info    { background: #dce8f5; color: #1B2B4B; border-left-color: var(--color-navy); }

/* ─── Tables ────────────────────────────────────────── */
.table-wrapper { overflow-x: auto; }
.table { width: 100%; border-collapse: collapse; }
.table th, .table td { padding: var(--space-3) var(--space-4); text-align: left; border-bottom: 1px solid var(--color-gray-200); }
.table th {
  font-family: var(--font-primary); font-size: 11px; font-weight: var(--fw-bold);
  color: var(--color-gray-500); background: var(--color-gray-50);
  text-transform: uppercase; letter-spacing: 0.06em;
}
.table tbody tr:hover { background: var(--color-gray-50); }

/* ─── Navbar ────────────────────────────────────────── */
.navbar {
  position: fixed; top: 0; left: 0; right: 0; height: var(--navbar-height);
  z-index: 1000; background: var(--color-white);
  border-bottom: 1px solid var(--color-gray-200);
  transition: background var(--transition-normal), box-shadow var(--transition-normal), border-color var(--transition-normal);
}
.navbar-transparent { background: transparent; border-bottom-color: transparent; }
.navbar-transparent .navbar-brand,
.navbar-transparent .navbar-link,
.navbar-transparent .navbar-username { color: var(--color-white); }
.navbar-transparent .navbar-link:hover { color: var(--color-gold); }
.navbar-transparent .lang-btn { color: var(--color-white); border-color: rgba(255,255,255,.6); }
.navbar-transparent .lang-btn.active { color: var(--color-gold); border-color: var(--color-gold); }
.navbar-transparent .navbar-messages { color: var(--color-white); }
.navbar-transparent .btn.btn-outline { color: var(--color-white); border-color: rgba(255,255,255,.8); background: transparent; }
.navbar-transparent .btn.btn-outline:hover { background: rgba(255,255,255,.12); color: var(--color-white); border-color: var(--color-white); }
.navbar-transparent .btn.btn-primary { background: transparent; border-color: rgba(255,255,255,.8); color: var(--color-white); }
.navbar-transparent .btn.btn-primary:hover { background: rgba(255,255,255,.12); color: var(--color-white); border-color: var(--color-white); }

.navbar-scrolled {
  background: rgba(255,255,255,.98); backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px); box-shadow: 0 1px 0 var(--color-gray-200);
  border-bottom-color: var(--color-gray-200);
}
.navbar-scrolled .navbar-brand,
.navbar-scrolled .navbar-link,
.navbar-scrolled .navbar-username { color: var(--color-navy); }
.navbar-scrolled .lang-btn { color: var(--color-gray-500); border-color: var(--color-gray-300); }
.navbar-scrolled .lang-btn.active { color: var(--color-gold); border-color: var(--color-gold); }
.navbar-scrolled .navbar-messages { color: var(--color-navy); }

.navbar-inner { display: flex; align-items: center; height: 100%; gap: var(--space-8); }
.navbar-brand {
  font-family: var(--font-display); font-size: var(--fs-lg);
  font-weight: var(--fw-bold); color: var(--color-navy);
  white-space: nowrap; flex-shrink: 0; display: flex;
  align-items: center; gap: var(--space-3); letter-spacing: -0.01em;
}
.navbar-brand-text { letter-spacing: -0.01em; }
.navbar-logo-img { height: 38px; width: auto; flex-shrink: 0; }
.navbar-toggle { display: none; flex-direction: column; gap: 5px; padding: var(--space-2); }
.navbar-toggle span { display: block; width: 22px; height: 2px; background: var(--color-navy); border-radius: 1px; transition: transform var(--transition-fast); }
.navbar-transparent .navbar-toggle span { background: var(--color-white); }
.navbar-scrolled .navbar-toggle span { background: var(--color-navy); }
.navbar-menu { display: flex; align-items: center; justify-content: space-between; flex: 1; }
.navbar-links { display: flex; align-items: center; gap: var(--space-6); }
.navbar-link {
  font-size: var(--fs-sm); font-weight: var(--fw-medium);
  color: var(--color-gray-600); transition: color var(--transition-fast);
  padding: var(--space-2) 0; letter-spacing: 0.02em;
}
.navbar-link:hover { color: var(--color-gold); }
.navbar-right { display: flex; align-items: center; gap: var(--space-4); }
.lang-switcher { display: flex; gap: var(--space-1); }
.lang-btn {
  padding: var(--space-1) var(--space-2); font-size: 11px;
  font-weight: var(--fw-bold); color: var(--color-gray-500);
  border: 1px solid var(--color-gray-300); border-radius: var(--radius-sm);
  cursor: pointer; transition: color var(--transition-fast), border-color var(--transition-fast);
  letter-spacing: 0.04em; text-transform: uppercase;
}
.lang-btn:hover { color: var(--color-navy); border-color: var(--color-navy); }
.lang-btn.active { color: var(--color-gold); border-color: var(--color-gold); }
.navbar-user { position: relative; }
.navbar-user-btn { display: flex; align-items: center; gap: var(--space-2); cursor: pointer; }
.navbar-avatar { width: 34px; height: 34px; border-radius: 50%; object-fit: cover; border: 2px solid var(--color-gray-200); }
.navbar-avatar-placeholder {
  width: 34px; height: 34px; border-radius: 50%;
  background: var(--color-navy); color: var(--color-white);
  display: inline-flex; align-items: center; justify-content: center;
  font-size: var(--fs-sm); font-weight: var(--fw-bold); border: 2px solid var(--color-navy-light);
}
.navbar-username { font-size: var(--fs-sm); font-weight: var(--fw-medium); color: var(--color-navy); }
.navbar-dropdown {
  display: none; position: absolute; top: calc(100% + var(--space-3)); right: 0;
  min-width: 200px; background: var(--color-white); border-radius: var(--radius-md);
  box-shadow: var(--shadow-lg); border: 1px solid var(--color-gray-200);
  padding: var(--space-2) 0; z-index: 100;
}
.navbar-dropdown.show { display: block; }
.navbar-dropdown a {
  display: block; padding: var(--space-3) var(--space-5); font-size: var(--fs-sm);
  color: var(--color-gray-700); transition: background var(--transition-fast), color var(--transition-fast);
}
.navbar-dropdown a:hover { background: var(--color-gray-50); color: var(--color-navy); }
.navbar-dropdown hr { border: none; border-top: 1px solid var(--color-gray-200); margin: var(--space-2) 0; }
.navbar-messages {
  position: relative; display: inline-flex; align-items: center;
  margin-right: var(--space-3); color: inherit; text-decoration: none;
  transition: color var(--transition-fast);
}
.navbar-messages:hover { color: var(--color-gold); }

body { padding-top: var(--navbar-height); }

/* ─── Responsive ────────────────────────────────────── */
@media (max-width: 768px) {
  :root { --navbar-height: 60px; }
  .container { padding: 0 var(--space-4); }
  .navbar-toggle { display: flex; }
  .navbar-menu {
    display: none; position: absolute; top: var(--navbar-height); left: 0; right: 0;
    background: var(--color-white); flex-direction: column;
    padding: var(--space-4) var(--space-6); border-bottom: 1px solid var(--color-gray-200);
    box-shadow: var(--shadow-md); z-index: 100;
    max-height: calc(100vh - var(--navbar-height)); overflow-y: auto;
  }
  .navbar-menu.open { display: flex; }
  .navbar-links { flex-direction: column; width: 100%; gap: 0; }
  .navbar-link {
    padding: var(--space-3) 0; border-bottom: 1px solid var(--color-gray-100);
    width: 100%; color: var(--color-navy); min-height: 44px; display: flex; align-items: center;
  }
  .navbar-right { flex-wrap: wrap; padding-top: var(--space-4); width: 100%; gap: var(--space-3); }
  .navbar-right .btn { flex: 1; min-width: 0; text-align: center; min-height: 44px; }
  .navbar-user-btn { min-height: 44px; }
  .navbar-dropdown {
    position: static; box-shadow: none; border: 1px solid var(--color-gray-200);
    border-radius: var(--radius-md); margin-top: var(--space-2);
  }
  .navbar-dropdown a { min-height: 44px; display: flex; align-items: center; }
  .form-input, .form-select, .form-textarea { font-size: 16px; min-height: 44px; }
  .btn { min-height: 44px; display: inline-flex; align-items: center; justify-content: center; }
}
@media (max-width: 480px) {
  .container { padding: 0 var(--space-3); }
  .btn { font-size: var(--fs-xs); padding: var(--space-2) var(--space-4); }
  .navbar-brand-text { font-size: var(--fs-sm); }
  .navbar-logo-img { height: 30px; }
}
@media (max-width: 360px) {
  .container { padding: 0 var(--space-2); }
}

/* ─── Loading Spinner Overlay ──────────────────────── */
.spinner-overlay {
  position: fixed;
  top: 0; left: 0; right: 0; bottom: 0;
  background: rgba(27,43,75,0.18);
  display: none;
  align-items: center;
  justify-content: center;
  z-index: 9999;
}
.spinner-overlay.active { display: flex; }
.spinner {
  width: 40px; height: 40px;
  border: 4px solid var(--color-gray-200);
  border-top-color: var(--color-gold);
  border-radius: 50%;
  animation: spin 0.7s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }

/* Button loading state */
.btn.is-loading {
  pointer-events: none;
  opacity: 0.7;
  position: relative;
}
.btn.is-loading::after {
  content: '';
  display: inline-block;
  width: 14px; height: 14px;
  border: 2px solid currentColor;
  border-top-color: transparent;
  border-radius: 50%;
  animation: spin 0.6s linear infinite;
  margin-left: 8px;
  vertical-align: middle;
}

/* ─── Breadcrumb (Admin) ───────────────────────────── */
.admin-breadcrumb {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  font-size: var(--fs-xs);
  color: var(--color-gray-400);
  margin-bottom: var(--space-4);
}
.admin-breadcrumb a {
  color: var(--color-navy);
  text-decoration: none;
}
.admin-breadcrumb a:hover {
  color: var(--color-gold);
}
.admin-breadcrumb .sep {
  color: var(--color-gray-300);
}

/* ─── Empty State ──────────────────────────────────── */
.empty-state-box {
  padding: var(--space-10);
  text-align: center;
  color: var(--color-gray-400);
}
.empty-state-box svg {
  margin-bottom: var(--space-4);
  color: var(--color-gray-300);
}
.empty-state-box p {
  font-size: var(--fs-sm);
  margin-bottom: var(--space-4);
}

/* ─── Gradient Course Placeholder ──────────────────── */
.gradient-placeholder {
  width: 100%;
  height: 160px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 2.5rem;
  color: rgba(255,255,255,0.6);
}
.gradient-placeholder.gp-1 { background: linear-gradient(135deg, #1B2B4B, #2A3F5F); }
.gradient-placeholder.gp-2 { background: linear-gradient(135deg, #2A3F5F, #C5A55A); }
.gradient-placeholder.gp-3 { background: linear-gradient(135deg, #0A1628, #1B2B4B); }
.gradient-placeholder.gp-4 { background: linear-gradient(135deg, #C5A55A, #B8972F); }
.gradient-placeholder.gp-5 { background: linear-gradient(135deg, #1B2B4B, #3A5A8F); }

/* ─── Progress Bar (course completion) ─────────────── */
.progress-bar-wrapper {
  width: 100%;
  height: 6px;
  background: var(--color-gray-100);
  border-radius: 3px;
  overflow: hidden;
  margin-top: var(--space-2);
}
.progress-bar-fill {
  height: 100%;
  border-radius: 3px;
  transition: width 0.6s ease;
  background: var(--color-gold);
}
.progress-bar-fill.complete {
  background: var(--color-success, #22c55e);
}