/**
 * Student Mobile Experience Styles (Vivid, Animated Mesh Gradient, Material 3 Expressive)
 * NTUquiz - Realtime Multiple-Choice Quiz Platform
 */

body.student-body {
  margin: 0;
  padding: 0;
  min-height: 100vh;
  background: linear-gradient(135deg, #0f172a 0%, #1e1b4b 50%, #172554 100%);
  color: #f8fafc;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: flex-start;
  font-family: var(--md-ref-typeface-plain);
  position: relative;
  overflow-x: hidden;
}

/* Animated Mesh Gradient Background Canvas */
#mesh-canvas {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  z-index: 0;
  pointer-events: none;
  opacity: 0.85;
}

/* Background gradient animation fallback */
.mesh-bg-fallback {
  position: fixed;
  inset: 0;
  background: radial-gradient(circle at 10% 20%, rgba(32, 106, 77, 0.45) 0%, transparent 50%),
              radial-gradient(circle at 90% 80%, rgba(61, 99, 115, 0.4) 0%, transparent 50%),
              radial-gradient(circle at 50% 50%, rgba(77, 99, 87, 0.35) 0%, transparent 60%);
  filter: blur(40px);
  z-index: 0;
  animation: meshFloat 12s ease-in-out infinite alternate;
}

@keyframes meshFloat {
  0% { transform: scale(1) translate(0, 0); }
  50% { transform: scale(1.1) translate(-20px, 15px); }
  100% { transform: scale(1) translate(20px, -15px); }
}

.student-container {
  position: relative;
  z-index: 10;
  width: 100%;
  max-width: 520px;
  min-height: 100vh;
  padding: 16px 16px 32px 16px;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

/* Student Top Bar */
.student-topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 16px;
  background: rgba(255, 255, 255, 0.12);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid rgba(255, 255, 255, 0.2);
  border-radius: var(--md-shape-corner-full);
}

.student-brand {
  display: flex;
  align-items: center;
  gap: 8px;
  font: var(--md-sys-typescale-title-medium);
  font-weight: 800;
  color: #ffffff;
}

.student-badge-info {
  display: flex;
  align-items: center;
  gap: 8px;
}

.streak-chip {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  background: rgba(234, 134, 0, 0.25);
  border: 1px solid #fdd663;
  color: #fef08a;
  padding: 4px 10px;
  border-radius: var(--md-shape-corner-full);
  font: var(--md-sys-typescale-label-small);
  font-weight: 700;
}

.score-chip {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  background: rgba(99, 102, 241, 0.3);
  border: 1px solid rgba(165, 180, 252, 0.5);
  color: #ffffff;
  padding: 4px 12px;
  border-radius: var(--md-shape-corner-full);
  font: var(--md-sys-typescale-label-medium);
  font-weight: 700;
}

/* Progress Bar */
.quiz-progress-track {
  width: 100%;
  height: 8px;
  background: rgba(255, 255, 255, 0.15);
  border-radius: var(--md-shape-corner-full);
  overflow: hidden;
  position: relative;
}

.quiz-progress-fill {
  height: 100%;
  width: 0%;
  background: linear-gradient(90deg, #38bdf8, #818cf8, #c084fc);
  border-radius: var(--md-shape-corner-full);
  transition: width 400ms cubic-bezier(0.2, 0, 0, 1);
}

/* Student Glass Card Base */
.student-card {
  background: rgba(255, 255, 255, 0.95);
  color: #0f172a;
  border-radius: var(--md-shape-corner-extra-large);
  padding: 24px;
  box-shadow: 0 12px 36px 0 rgba(0, 0, 0, 0.35);
  border: 1px solid rgba(255, 255, 255, 0.8);
  display: flex;
  flex-direction: column;
  gap: 20px;
  animation: slideUp 300ms cubic-bezier(0.05, 0.7, 0.1, 1.0);
}

@keyframes slideUp {
  from { opacity: 0; transform: translateY(16px); }
  to { opacity: 1; transform: translateY(0); }
}

/* Join & Lobby Screen */
.join-header {
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
}

.join-icon-avatar {
  width: 64px;
  height: 64px;
  border-radius: 50%;
  background: linear-gradient(135deg, #0284c7, #6366f1);
  color: #ffffff;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 4px 14px rgba(2, 132, 199, 0.4);
}

.waiting-pulse-box {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 32px 16px;
  text-align: center;
  gap: 16px;
}

.lobby-spinner {
  width: 56px;
  height: 56px;
  border: 4px solid rgba(99, 102, 241, 0.2);
  border-top-color: #4f46e5;
  border-radius: 50%;
  animation: spin 1s linear infinite;
}

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

/* Active Question Display */
.question-badge-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.question-counter-badge {
  font: var(--md-sys-typescale-label-large);
  font-weight: 700;
  color: var(--md-sys-color-primary);
  background-color: var(--md-sys-color-primary-container);
  padding: 4px 12px;
  border-radius: var(--md-shape-corner-full);
}

.question-content-box {
  font: var(--md-sys-typescale-title-large);
  font-size: 19px;
  line-height: 1.5;
  color: #0f172a;
  word-break: break-word;
}

/* Choice Buttons Container */
.choices-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.choice-btn {
  width: 100%;
  min-height: 58px;
  padding: 14px 18px;
  border-radius: var(--md-shape-corner-large);
  border: 2px solid transparent;
  background-color: #f1f5f9;
  color: #1e293b;
  display: flex;
  align-items: center;
  gap: 14px;
  font: var(--md-sys-typescale-body-large);
  font-weight: 600;
  text-align: left;
  cursor: pointer;
  outline: none;
  transition: all 200ms cubic-bezier(0.2, 0, 0, 1);
  position: relative;
  user-select: none;
}

.choice-btn:hover:not(:disabled) {
  background-color: #e2e8f0;
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
}

.choice-btn:active:not(:disabled) {
  transform: scale(0.98);
}

.choice-letter-tag {
  width: 34px;
  height: 34px;
  min-width: 34px;
  border-radius: var(--md-shape-corner-medium);
  background-color: #ffffff;
  color: #0f172a;
  font-weight: 800;
  font-size: 15px;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.08);
  transition: all 200ms ease;
}

.choice-text {
  flex: 1;
  word-break: break-word;
}

/* Choice Selection & Feedback States */
.choice-btn.selected {
  border-color: var(--md-sys-color-primary);
  background-color: #e0f2fe;
}

.choice-btn.selected .choice-letter-tag {
  background-color: var(--md-sys-color-primary);
  color: #ffffff;
}

/* Correct state */
.choice-btn.correct {
  border-color: #16a34a !important;
  background-color: #dcfce7 !important;
  color: #14532d !important;
}

.choice-btn.correct .choice-letter-tag {
  background-color: #16a34a !important;
  color: #ffffff !important;
}

/* Incorrect state */
.choice-btn.incorrect {
  border-color: #dc2626 !important;
  background-color: #fee2e2 !important;
  color: #7f1d1d !important;
  animation: shake 350ms ease;
}

.choice-btn.incorrect .choice-letter-tag {
  background-color: #dc2626 !important;
  color: #ffffff !important;
}

@keyframes shake {
  0%, 100% { transform: translateX(0); }
  25% { transform: translateX(-6px); }
  75% { transform: translateX(6px); }
}

.choice-btn:disabled {
  cursor: default;
  transform: none !important;
}

/* Instant Explanation Card */
.explanation-card {
  display: none;
  flex-direction: column;
  gap: 10px;
  background: #f8fafc;
  border: 1px solid #cbd5e1;
  border-radius: var(--md-shape-corner-medium);
  padding: 16px;
  animation: expandIn 250ms cubic-bezier(0.05, 0.7, 0.1, 1.0);
}

.explanation-card.active {
  display: flex;
}

@keyframes expandIn {
  from { opacity: 0; transform: translateY(8px); }
  to { opacity: 1; transform: translateY(0); }
}

.explanation-header {
  display: flex;
  align-items: center;
  gap: 8px;
  font: var(--md-sys-typescale-title-small);
  font-weight: 700;
  color: #334155;
}

.explanation-body {
  font: var(--md-sys-typescale-body-medium);
  color: #475569;
  line-height: 1.5;
}

/* Continue Button Row */
.action-continue-row {
  margin-top: 8px;
  display: flex;
  justify-content: flex-end;
}

/* Finish Summary Screen */
.summary-hero-card {
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 16px;
  padding: 32px 20px;
}

.score-circle-display {
  width: 110px;
  height: 110px;
  border-radius: 50%;
  background: linear-gradient(135deg, #0284c7, #6366f1);
  color: #ffffff;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  box-shadow: 0 8px 24px rgba(99, 102, 241, 0.4);
}

.score-circle-num {
  font: var(--md-sys-typescale-headline-large);
  font-weight: 800;
  line-height: 1;
}

.score-circle-lbl {
  font: var(--md-sys-typescale-label-small);
  opacity: 0.9;
}

.summary-stats-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
  width: 100%;
}

.summary-stat-box {
  background-color: #f1f5f9;
  border-radius: var(--md-shape-corner-medium);
  padding: 14px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
}

.summary-stat-box .val {
  font: var(--md-sys-typescale-title-large);
  font-weight: 700;
  color: #0f172a;
}

.summary-stat-box .lbl {
  font: var(--md-sys-typescale-label-small);
  color: #64748b;
}

/* Summary Question Review List */
.review-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
  width: 100%;
  margin-top: 12px;
}

.review-item-card {
  background-color: #ffffff;
  border-radius: var(--md-shape-corner-large);
  border: 1px solid #e2e8f0;
  padding: 16px;
  display: flex;
  flex-direction: column;
  gap: 8px;
  text-align: left;
}

.review-item-card.is-correct {
  border-left: 5px solid #16a34a;
}

.review-item-card.is-wrong {
  border-left: 5px solid #dc2626;
}