/**
 * UPDC MCQ Platform - Main Styles
 * Global styles, layouts, and page structure
 */

/* ============================================================
   CSS RESET & BASE
   ============================================================ */

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

html {
  scroll-behavior: smooth;
}

body {
  min-height: 100vh;
  overflow-x: hidden;
}

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

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

p,
h1,
h2,
h3,
h4,
h5,
h6 {
  overflow-wrap: break-word;
}

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

a:hover {
  color: var(--color-cyan-dark);
}

ul,
ol {
  list-style: none;
}

/* ============================================================
   TYPOGRAPHY
   ============================================================ */

h1, h2 {
  font-family: var(--font-display);
  font-weight: var(--font-weight-bold);
  line-height: var(--line-height-tight);
  color: var(--color-text-primary);
}

h3, h4, h5, h6 {
  font-family: var(--font-body);
  font-weight: var(--font-weight-semibold);
  line-height: var(--line-height-snug);
  color: var(--color-text-primary);
}

h1 {
  font-size: var(--text-display-lg);
  margin-bottom: var(--space-6);
}

h2 {
  font-size: var(--text-heading-xl);
  margin-bottom: var(--space-5);
}

h3 {
  font-size: var(--text-heading-lg);
  margin-bottom: var(--space-4);
}

h4 {
  font-size: var(--text-heading-md);
  margin-bottom: var(--space-3);
}

p {
  margin-bottom: var(--space-4);
  max-width: 75ch;
}

.lead {
  font-size: var(--text-body-lg);
  color: var(--color-text-secondary);
}

.small {
  font-size: var(--text-body-sm);
}

.caption {
  font-size: var(--text-caption);
  color: var(--color-text-muted);
}

.overline {
  font-size: var(--text-overline);
  font-weight: var(--font-weight-semibold);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-text-secondary);
}

/* Quiz content font */
.quiz-text {
  font-family: var(--font-quiz);
}

/* ============================================================
   LAYOUT CONTAINERS
   ============================================================ */

#app {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

#app-header {
  position: sticky;
  top: 0;
  z-index: var(--z-sticky);
  background: var(--color-surface-card);
  box-shadow: var(--shadow-flat-md);
}

#app-main {
  flex: 1;
  display: flex;
  flex-direction: column;
}

.container {
  width: 100%;
  max-width: var(--container-xl);
  margin: 0 auto;
  padding: 0 var(--space-6);
}

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

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

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

.container--full {
  max-width: none;
}

/* Page wrapper with sidebar support */
.page-wrapper {
  display: flex;
  min-height: calc(100vh - 72px); /* Subtract header height */
}

.page-sidebar {
  width: 280px;
  flex-shrink: 0;
  background: var(--color-surface-card);
  border-right: 1px solid var(--color-border);
  padding: var(--space-6);
}

.page-content {
  flex: 1;
  padding: var(--space-8);
  overflow-y: auto;
}

/* ============================================================
   LOADING SCREEN
   ============================================================ */

.loading-screen {
  position: fixed;
  inset: 0;
  background: var(--color-surface);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: var(--z-max);
  transition: opacity var(--duration-slow) var(--easing-out);
}

.loading-screen.fade-out {
  opacity: 0;
  pointer-events: none;
}

.loading-content {
  text-align: center;
}

.loading-logo {
  width: 120px;
  height: auto;
  margin: 0 auto var(--space-6);
  animation: pulse 2s ease-in-out infinite;
}

.loading-title {
  font-family: var(--font-display);
  font-size: var(--text-heading-xl);
  color: var(--color-green);
  margin-bottom: var(--space-2);
}

.loading-subtitle {
  font-size: var(--text-body-md);
  color: var(--color-text-secondary);
  margin-bottom: 0;
}

@keyframes pulse {
  0%, 100% {
    transform: scale(1);
    opacity: 1;
  }
  50% {
    transform: scale(1.05);
    opacity: 0.8;
  }
}

/* ============================================================
   SECTION & GRID UTILITIES
   ============================================================ */

.section {
  padding: var(--space-12) 0;
}

.section--sm {
  padding: var(--space-8) 0;
}

.section--lg {
  padding: var(--space-16) 0;
}

.grid {
  display: grid;
  gap: var(--grid-gap);
}

.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-fit, minmax(280px, 1fr));
}

/* Flexbox utilities */
.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); }

/* ============================================================
   SPACING UTILITIES
   ============================================================ */

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

.mt-0 { margin-top: var(--space-0); }
.mt-2 { margin-top: var(--space-2); }
.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: var(--space-0); }
.mb-2 { margin-bottom: var(--space-2); }
.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; }

.p-0 { padding: var(--space-0); }
.p-2 { padding: var(--space-2); }
.p-3 { padding: var(--space-3); }
.p-4 { padding: var(--space-4); }
.p-6 { padding: var(--space-6); }
.p-8 { padding: var(--space-8); }

.px-4 { padding-left: var(--space-4); padding-right: var(--space-4); }
.px-6 { padding-left: var(--space-6); padding-right: var(--space-6); }
.py-4 { padding-top: var(--space-4); padding-bottom: var(--space-4); }
.py-6 { padding-top: var(--space-6); padding-bottom: var(--space-6); }

/* ============================================================
   TEXT UTILITIES
   ============================================================ */

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

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

.line-clamp-2 {
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.line-clamp-3 {
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

/* ============================================================
   VISIBILITY UTILITIES
   ============================================================ */

.hidden {
  display: none !important;
}

.invisible {
  visibility: hidden;
}

.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;
}

/* ============================================================
   TOAST NOTIFICATIONS
   ============================================================ */

.toast-container {
  position: fixed;
  bottom: var(--space-6);
  right: var(--space-6);
  z-index: var(--z-toast);
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  pointer-events: none;
}

.toast {
  background: var(--color-surface-card);
  border-radius: var(--radius-lg);
  padding: var(--space-4) var(--space-6);
  box-shadow: var(--shadow-clay-lg);
  display: flex;
  align-items: center;
  gap: var(--space-3);
  min-width: 300px;
  max-width: 450px;
  pointer-events: auto;
  animation: slideInRight var(--duration-normal) var(--easing-out);
}

.toast--success {
  border-left: 4px solid var(--color-lime);
}

.toast--error {
  border-left: 4px solid var(--color-error);
}

.toast--warning {
  border-left: 4px solid var(--color-warning);
}

.toast--info {
  border-left: 4px solid var(--color-cyan);
}

.toast__icon {
  width: 24px;
  height: 24px;
  flex-shrink: 0;
}

.toast__content {
  flex: 1;
}

.toast__title {
  font-weight: var(--font-weight-semibold);
  margin-bottom: var(--space-1);
}

.toast__message {
  font-size: var(--text-body-sm);
  color: var(--color-text-secondary);
  margin: 0;
}

.toast__close {
  background: none;
  border: none;
  padding: var(--space-1);
  cursor: pointer;
  color: var(--color-text-muted);
  transition: color var(--transition-fast);
}

.toast__close:hover {
  color: var(--color-text-primary);
}

.toast.fade-out {
  animation: slideOutRight var(--duration-normal) var(--easing-in) forwards;
}

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

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

/* ============================================================
   MODAL
   ============================================================ */

.modal-container {
  display: none;
}

.modal-container.active {
  display: block;
}

.modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.5);
  z-index: var(--z-overlay);
  animation: fadeIn var(--duration-fast) var(--easing-out);
}

.modal {
  position: fixed;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  background: var(--color-surface-card);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-clay-xl);
  z-index: var(--z-modal);
  width: 90%;
  max-width: 500px;
  max-height: 90vh;
  overflow: hidden;
  animation: scaleIn var(--duration-normal) var(--easing-out);
}

.modal--lg {
  max-width: 700px;
}

.modal--xl {
  max-width: 900px;
}

.modal__header {
  padding: var(--space-6);
  border-bottom: 1px solid var(--color-border);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.modal__title {
  font-family: var(--font-display);
  font-size: var(--text-heading-lg);
  margin: 0;
}

.modal__close {
  background: none;
  border: none;
  padding: var(--space-2);
  cursor: pointer;
  color: var(--color-text-muted);
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
}

.modal__close:hover {
  background: var(--color-surface);
  color: var(--color-text-primary);
}

.modal__body {
  padding: var(--space-6);
  overflow-y: auto;
  max-height: calc(90vh - 140px);
}

.modal__footer {
  padding: var(--space-4) var(--space-6);
  border-top: 1px solid var(--color-border);
  display: flex;
  justify-content: flex-end;
  gap: var(--space-3);
}

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

@keyframes scaleIn {
  from {
    transform: translate(-50%, -50%) scale(0.95);
    opacity: 0;
  }
  to {
    transform: translate(-50%, -50%) scale(1);
    opacity: 1;
  }
}

/* ============================================================
   EMPTY STATES
   ============================================================ */

.empty-state {
  text-align: center;
  padding: var(--space-12) var(--space-6);
}

.empty-state__icon {
  width: 80px;
  height: 80px;
  margin: 0 auto var(--space-6);
  color: var(--color-text-muted);
}

.empty-state__title {
  font-size: var(--text-heading-md);
  margin-bottom: var(--space-2);
}

.empty-state__description {
  color: var(--color-text-secondary);
  margin-bottom: var(--space-6);
  max-width: 400px;
  margin-left: auto;
  margin-right: auto;
}

/* ============================================================
   RESPONSIVE BREAKPOINTS
   ============================================================ */

@media (max-width: 1023px) {
  .page-sidebar {
    width: 240px;
  }

  .grid--4 {
    grid-template-columns: repeat(2, 1fr);
  }

  .grid--3 {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 767px) {
  .page-wrapper {
    flex-direction: column;
  }

  .page-sidebar {
    width: 100%;
    border-right: none;
    border-bottom: 1px solid var(--color-border);
  }

  .page-content {
    padding: var(--space-6);
  }

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

  .container {
    padding: 0 var(--space-4);
  }

  h1 {
    font-size: var(--text-heading-xl);
  }

  h2 {
    font-size: var(--text-heading-lg);
  }

  .modal {
    width: 95%;
    max-height: 95vh;
  }

  .toast-container {
    left: var(--space-4);
    right: var(--space-4);
    bottom: var(--space-4);
  }

  .toast {
    min-width: auto;
    width: 100%;
  }
}