/* =============================================================================
   AI CLASS — MAIN STYLESHEET
   Domain: aiclass.com.ng
   =============================================================================
   Design tokens, resets, typography, and shared components used across
   every page of the platform.
   ============================================================================= */

/* -----------------------------------------------------------------------------
   DESIGN TOKENS
   ----------------------------------------------------------------------------- */
:root {
  /* Brand */
  --color-primary: #0a3d62;
  --color-primary-light: #1e5a8a;
  --color-primary-dark: #062a44;
  --color-accent: #d4af37;
  --color-accent-light: #e6c65a;

  /* Status */
  --color-success: #16a34a;
  --color-success-bg: #f0fdf4;
  --color-error: #dc2626;
  --color-error-bg: #fef2f2;
  --color-warning: #d97706;
  --color-warning-bg: #fffbeb;
  --color-info: #2563eb;
  --color-info-bg: #eff6ff;

  /* Neutrals */
  --color-bg: #f8fafc;
  --color-surface: #ffffff;
  --color-border: #e2e8f0;
  --color-border-strong: #cbd5e1;
  --color-text: #0f172a;
  --color-text-muted: #64748b;
  --color-text-subtle: #94a3b8;

  /* Typography */
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
    "Helvetica Neue", Arial, sans-serif;
  --font-serif: Georgia, "Times New Roman", serif;
  --font-mono: "SF Mono", Monaco, "Cascadia Code", "Roboto Mono", Menlo,
    Consolas, monospace;

  --text-xs: 0.75rem;
  --text-sm: 0.875rem;
  --text-base: 1rem;
  --text-lg: 1.125rem;
  --text-xl: 1.25rem;
  --text-2xl: 1.5rem;
  --text-3xl: 1.875rem;
  --text-4xl: 2.25rem;
  --text-5xl: 3rem;

  /* Spacing */
  --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;

  /* Radius */
  --radius-sm: 4px;
  --radius: 8px;
  --radius-lg: 12px;
  --radius-xl: 16px;
  --radius-full: 9999px;

  /* Shadows */
  --shadow-sm: 0 1px 2px rgba(15, 23, 42, 0.06);
  --shadow: 0 2px 8px rgba(15, 23, 42, 0.08);
  --shadow-md: 0 4px 16px rgba(15, 23, 42, 0.1);
  --shadow-lg: 0 12px 32px rgba(15, 23, 42, 0.12);

  /* Layout */
  --container: 1200px;
  --container-narrow: 720px;
  --container-wide: 1440px;
  --sidebar-width: 260px;
  --header-height: 64px;

  /* Transitions */
  --transition-fast: 120ms ease;
  --transition: 200ms ease;
  --transition-slow: 320ms ease;
}

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

html {
  -webkit-text-size-adjust: 100%;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-sans);
  font-size: var(--text-base);
  line-height: 1.6;
  color: var(--color-text);
  background: var(--color-bg);
  min-height: 100vh;
}

img,
picture,
svg,
video {
  max-width: 100%;
  display: block;
}

button {
  font: inherit;
  cursor: pointer;
  border: none;
  background: none;
  color: inherit;
}

input,
textarea,
select {
  font: inherit;
  color: inherit;
}

a {
  color: var(--color-primary);
  text-decoration: none;
  transition: color var(--transition-fast);
}

a:hover {
  color: var(--color-primary-light);
}

ul,
ol {
  list-style: none;
}

/* -----------------------------------------------------------------------------
   TYPOGRAPHY
   ----------------------------------------------------------------------------- */
h1,
h2,
h3,
h4,
h5,
h6 {
  font-weight: 700;
  line-height: 1.25;
  color: var(--color-text);
  letter-spacing: -0.01em;
}

h1 { font-size: var(--text-4xl); }
h2 { font-size: var(--text-3xl); }
h3 { font-size: var(--text-2xl); }
h4 { font-size: var(--text-xl); }
h5 { font-size: var(--text-lg); }
h6 { font-size: var(--text-base); }

p { margin-bottom: var(--space-4); }
p:last-child { margin-bottom: 0; }

code,
pre {
  font-family: var(--font-mono);
  font-size: 0.9em;
}

code {
  background: #f1f5f9;
  padding: 2px 6px;
  border-radius: var(--radius-sm);
  color: #be123c;
}

pre {
  background: #0f172a;
  color: #e2e8f0;
  padding: var(--space-4);
  border-radius: var(--radius);
  overflow-x: auto;
  line-height: 1.5;
}

pre code {
  background: transparent;
  color: inherit;
  padding: 0;
}

/* -----------------------------------------------------------------------------
   LAYOUT
   ----------------------------------------------------------------------------- */
.container {
  width: 100%;
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 var(--space-4);
}

.container-narrow {
  max-width: var(--container-narrow);
}

.container-wide {
  max-width: var(--container-wide);
}

.flex { display: flex; }
.flex-col { flex-direction: column; }
.flex-wrap { flex-wrap: wrap; }
.items-center { align-items: center; }
.items-start { align-items: flex-start; }
.items-end { align-items: flex-end; }
.justify-center { justify-content: center; }
.justify-between { justify-content: space-between; }
.justify-end { justify-content: flex-end; }
.gap-1 { gap: var(--space-1); }
.gap-2 { gap: var(--space-2); }
.gap-3 { gap: var(--space-3); }
.gap-4 { gap: var(--space-4); }
.gap-6 { gap: var(--space-6); }
.gap-8 { gap: var(--space-8); }

.grid { display: grid; }
.grid-2 { grid-template-columns: repeat(2, 1fr); }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-4 { grid-template-columns: repeat(4, 1fr); }
.grid-auto { grid-template-columns: repeat(auto-fill, minmax(240px, 1fr)); }

.text-center { text-align: center; }
.text-right { text-align: right; }
.text-left { text-align: left; }

.hidden { display: none !important; }
.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: var(--space-3) var(--space-5);
  font-size: var(--text-sm);
  font-weight: 600;
  border-radius: var(--radius);
  transition: all var(--transition);
  white-space: nowrap;
  cursor: pointer;
  border: 1px solid transparent;
  line-height: 1.2;
}

.btn:disabled {
  opacity: 0.55;
  cursor: not-allowed;
}

.btn-primary {
  background: var(--color-primary);
  color: #fff;
}
.btn-primary:hover:not(:disabled) {
  background: var(--color-primary-light);
  color: #fff;
}

.btn-accent {
  background: var(--color-accent);
  color: var(--color-primary-dark);
}
.btn-accent:hover:not(:disabled) {
  background: var(--color-accent-light);
}

.btn-secondary {
  background: var(--color-surface);
  color: var(--color-text);
  border-color: var(--color-border-strong);
}
.btn-secondary:hover:not(:disabled) {
  background: var(--color-bg);
  border-color: var(--color-primary);
  color: var(--color-primary);
}

.btn-danger {
  background: var(--color-error);
  color: #fff;
}
.btn-danger:hover:not(:disabled) {
  background: #b91c1c;
}

.btn-ghost {
  background: transparent;
  color: var(--color-primary);
}
.btn-ghost:hover:not(:disabled) {
  background: rgba(10, 61, 98, 0.08);
}

.btn-sm {
  padding: var(--space-2) var(--space-3);
  font-size: var(--text-xs);
}

.btn-lg {
  padding: var(--space-4) var(--space-6);
  font-size: var(--text-base);
}

.btn-block {
  width: 100%;
}

/* -----------------------------------------------------------------------------
   FORMS
   ----------------------------------------------------------------------------- */
.form-group {
  margin-bottom: var(--space-5);
}

.form-label {
  display: block;
  font-size: var(--text-sm);
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: var(--space-2);
}

.form-label .required {
  color: var(--color-error);
  margin-left: 2px;
}

.form-hint {
  display: block;
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  margin-top: var(--space-1);
}

.form-input,
.form-select,
.form-textarea {
  width: 100%;
  padding: var(--space-3) var(--space-4);
  font-size: var(--text-base);
  color: var(--color-text);
  background: var(--color-surface);
  border: 1px solid var(--color-border-strong);
  border-radius: var(--radius);
  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-primary);
  box-shadow: 0 0 0 3px rgba(10, 61, 98, 0.12);
}

.form-input:disabled,
.form-select:disabled,
.form-textarea:disabled {
  background: var(--color-bg);
  color: var(--color-text-muted);
  cursor: not-allowed;
}

.form-textarea {
  resize: vertical;
  min-height: 100px;
  font-family: inherit;
}

.form-error {
  display: none;
  padding: var(--space-3) var(--space-4);
  background: var(--color-error-bg);
  color: var(--color-error);
  border: 1px solid #fecaca;
  border-radius: var(--radius);
  font-size: var(--text-sm);
  margin-bottom: var(--space-4);
}

.form-error.visible {
  display: block;
}

.form-success {
  display: none;
  padding: var(--space-3) var(--space-4);
  background: var(--color-success-bg);
  color: var(--color-success);
  border: 1px solid #bbf7d0;
  border-radius: var(--radius);
  font-size: var(--text-sm);
  margin-bottom: var(--space-4);
}

.form-success.visible {
  display: block;
}

.form-checkbox {
  display: flex;
  align-items: flex-start;
  gap: var(--space-3);
  cursor: pointer;
  font-size: var(--text-sm);
  line-height: 1.5;
}

.form-checkbox input[type="checkbox"] {
  width: 18px;
  height: 18px;
  flex-shrink: 0;
  margin-top: 2px;
  accent-color: var(--color-primary);
  cursor: pointer;
}

/* -----------------------------------------------------------------------------
   CARDS
   ----------------------------------------------------------------------------- */
.card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  box-shadow: var(--shadow-sm);
}

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

.card-header {
  margin-bottom: var(--space-4);
  padding-bottom: var(--space-4);
  border-bottom: 1px solid var(--color-border);
}

.card-title {
  font-size: var(--text-lg);
  font-weight: 700;
  color: var(--color-text);
}

.card-subtitle {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  margin-top: var(--space-1);
}

/* -----------------------------------------------------------------------------
   BADGES
   ----------------------------------------------------------------------------- */
.badge {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  padding: 2px 10px;
  font-size: var(--text-xs);
  font-weight: 600;
  border-radius: var(--radius-full);
  letter-spacing: 0.02em;
  text-transform: uppercase;
}

.badge-success { background: var(--color-success-bg); color: var(--color-success); }
.badge-error { background: var(--color-error-bg); color: var(--color-error); }
.badge-warning { background: var(--color-warning-bg); color: var(--color-warning); }
.badge-info { background: var(--color-info-bg); color: var(--color-info); }
.badge-neutral { background: #f1f5f9; color: var(--color-text-muted); }

/* -----------------------------------------------------------------------------
   TABLES
   ----------------------------------------------------------------------------- */
.table-wrap {
  overflow-x: auto;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  background: var(--color-surface);
}

.table {
  width: 100%;
  border-collapse: collapse;
  font-size: var(--text-sm);
}

.table thead {
  background: #f8fafc;
}

.table th {
  text-align: left;
  padding: var(--space-3) var(--space-4);
  font-weight: 600;
  color: var(--color-text-muted);
  font-size: var(--text-xs);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  border-bottom: 1px solid var(--color-border);
  white-space: nowrap;
}

.table td {
  padding: var(--space-3) var(--space-4);
  border-bottom: 1px solid var(--color-border);
  vertical-align: middle;
}

.table tbody tr:last-child td {
  border-bottom: none;
}

.table tbody tr:hover {
  background: #f8fafc;
}

/* -----------------------------------------------------------------------------
   STATES
   ----------------------------------------------------------------------------- */
.loading-state,
.empty-state,
.error-state {
  text-align: center;
  padding: var(--space-12) var(--space-4);
  color: var(--color-text-muted);
}

.spinner {
  display: inline-block;
  width: 32px;
  height: 32px;
  border: 3px solid var(--color-border);
  border-top-color: var(--color-primary);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
  margin-bottom: var(--space-3);
}

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

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

@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

/* -----------------------------------------------------------------------------
   TOAST (position and animation; colors are set inline by utils.js)
   ----------------------------------------------------------------------------- */
.toast {
  animation: slideIn 0.25s ease;
}

/* -----------------------------------------------------------------------------
   UTILITIES
   ----------------------------------------------------------------------------- */
.mt-0 { margin-top: 0; }
.mt-1 { margin-top: var(--space-1); }
.mt-2 { margin-top: var(--space-2); }
.mt-3 { margin-top: var(--space-3); }
.mt-4 { margin-top: var(--space-4); }
.mt-6 { margin-top: var(--space-6); }
.mt-8 { margin-top: var(--space-8); }

.mb-0 { margin-bottom: 0; }
.mb-1 { margin-bottom: var(--space-1); }
.mb-2 { margin-bottom: var(--space-2); }
.mb-3 { margin-bottom: var(--space-3); }
.mb-4 { margin-bottom: var(--space-4); }
.mb-6 { margin-bottom: var(--space-6); }
.mb-8 { margin-bottom: var(--space-8); }

.ml-auto { margin-left: auto; }
.mr-auto { margin-right: auto; }
.mx-auto { margin-left: auto; margin-right: auto; }

.w-full { width: 100%; }
.h-full { height: 100%; }
.max-w-sm { max-width: 24rem; }
.max-w-md { max-width: 32rem; }
.max-w-lg { max-width: 48rem; }

.font-medium { font-weight: 500; }
.font-semibold { font-weight: 600; }
.font-bold { font-weight: 700; }

.text-xs { font-size: var(--text-xs); }
.text-sm { font-size: var(--text-sm); }
.text-lg { font-size: var(--text-lg); }
.text-xl { font-size: var(--text-xl); }
.text-2xl { font-size: var(--text-2xl); }

.text-muted { color: var(--color-text-muted); }
.text-subtle { color: var(--color-text-subtle); }
.text-primary { color: var(--color-primary); }
.text-error { color: var(--color-error); }
.text-success { color: var(--color-success); }

.bg-surface { background: var(--color-surface); }
.bg-muted { background: var(--color-bg); }

.border { border: 1px solid var(--color-border); }
.border-top { border-top: 1px solid var(--color-border); }
.border-bottom { border-bottom: 1px solid var(--color-border); }

.rounded { border-radius: var(--radius); }
.rounded-lg { border-radius: var(--radius-lg); }
.rounded-full { border-radius: var(--radius-full); }

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

.overflow-hidden { overflow: hidden; }
.truncate {
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

/* -----------------------------------------------------------------------------
   RESPONSIVE
   ----------------------------------------------------------------------------- */
@media (max-width: 768px) {
  h1 { font-size: var(--text-3xl); }
  h2 { font-size: var(--text-2xl); }
  h3 { font-size: var(--text-xl); }

  .grid-2,
  .grid-3,
  .grid-4 {
    grid-template-columns: 1fr;
  }

  .card {
    padding: var(--space-4);
  }
}

@media (max-width: 480px) {
  :root {
    --text-4xl: 1.75rem;
    --text-3xl: 1.5rem;
  }

  .container {
    padding: 0 var(--space-3);
  }
}

/* -----------------------------------------------------------------------------
   PRINT
   ----------------------------------------------------------------------------- */
@media print {
  body { background: #fff; }
  .no-print { display: none !important; }
  .btn { display: none !important; }
}