/* ============================================================
   VIETBCC — DESIGN SYSTEM COMPONENTS
   Mọi trang phải dùng những class này thay vì tự viết CSS riêng.
   ============================================================ */

/* ---------- Button ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  min-height: 56px;
  padding: var(--space-3) var(--space-6);
  border: none;
  border-radius: var(--radius-pill);
  font-family: var(--font-family);
  font-weight: 700;
  font-size: var(--font-size-lg);
  color: var(--color-white);
  background: var(--color-primary);
  box-shadow: var(--shadow-button);
  transition: transform var(--duration-fast) var(--ease-bounce),
              box-shadow var(--duration-fast) var(--ease-bounce);
}

.btn:hover {
  transform: translateY(-2px);
}

.btn:active {
  transform: translateY(3px);
  box-shadow: 0 3px 0 var(--color-primary-dark);
}

.btn-secondary {
  background: var(--color-secondary);
  box-shadow: 0 6px 0 #00a19c;
}

.btn-secondary:active {
  box-shadow: 0 3px 0 #00a19c;
}

.btn-outline {
  background: var(--color-white);
  color: var(--color-primary);
  box-shadow: 0 4px 0 var(--color-border);
  border: 2px solid var(--color-border);
}

.btn-outline:active {
  box-shadow: 0 2px 0 var(--color-border);
}

.btn-block {
  width: 100%;
}

/* ---------- Card ---------- */
.card {
  background: var(--gradient-card);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
  padding: var(--space-5);
}

.card-flat {
  background: var(--color-bg-alt);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-sm);
  padding: var(--space-4);
}

/* Gentle floating animation for cute/game feel */
.card-floating {
  animation: float 4s ease-in-out infinite;
}

@keyframes float {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-8px); }
}

/* ---------- Badge ---------- */
.badge {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  padding: var(--space-1) var(--space-3);
  border-radius: var(--radius-pill);
  font-size: var(--font-size-sm);
  font-weight: 700;
  background: var(--color-accent);
  color: #7a4f00;
}

.badge-success { background: var(--color-success); color: var(--color-white); }
.badge-info { background: var(--color-info); color: var(--color-white); }
.badge-coins { background: #fff3cd; color: #856404; border: 1px solid #ffeeba; }
.badge-accent { background: var(--color-accent); color: #7a4f00; }

/* ---------- Avatar ---------- */
.avatar {
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: var(--color-white);
  box-shadow: var(--shadow-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: var(--font-size-lg);
  flex-shrink: 0;
}

/* ---------- Progress ---------- */
.progress {
  width: 100%;
  height: 14px;
  border-radius: var(--radius-pill);
  background: var(--color-border);
  overflow: hidden;
}

.progress-bar {
  height: 100%;
  border-radius: var(--radius-pill);
  background: var(--gradient-sun);
  transition: width var(--duration-slow) var(--ease-bounce);
}

/* ---------- Alert (flash messages) ---------- */
.alert-stack {
  position: fixed;
  top: var(--space-4);
  left: 50%;
  transform: translateX(-50%);
  z-index: var(--z-toast);
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  width: min(92vw, 420px);
}

.alert {
  padding: var(--space-3) var(--space-4);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-md);
  font-weight: 600;
  font-size: var(--font-size-sm);
  color: var(--color-white);
  animation: alert-in var(--duration-base) var(--ease-bounce);
}

@keyframes alert-in {
  from { opacity: 0; transform: translateY(-12px); }
  to { opacity: 1; transform: translateY(0); }
}

.alert-error { background: var(--color-danger); }
.alert-success { background: var(--color-success); }

/* ---------- Site header / nav ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: var(--z-header);
  background: var(--color-bg-alt);
  box-shadow: var(--shadow-sm);
}

.site-header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-3);
  padding-block: var(--space-3);
}

.site-logo {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  font-weight: 800;
  font-size: var(--font-size-lg);
  color: var(--color-primary);
}

.site-nav-actions {
  display: flex;
  align-items: center;
  gap: var(--space-3);
}

.site-nav-user {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  font-weight: 700;
  font-size: var(--font-size-sm);
  color: var(--color-text);
  text-decoration: none;
  transition: transform var(--duration-fast);
}

.site-nav-user:hover {
  transform: translateY(-1px);
}

.site-nav-name {
  font-weight: 700;
  max-width: 120px;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.btn-sm {
  min-height: 40px;
  padding: var(--space-2) var(--space-4);
  font-size: var(--font-size-sm);
}

/* ---------- Form (register/login) ---------- */
.auth-page {
  min-height: 100dvh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: var(--space-5) var(--space-4);
  background: var(--gradient-hero);
}

.auth-card {
  width: 100%;
  max-width: 420px;
  background: var(--color-white);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  padding: var(--space-6);
}

.auth-mascot {
  text-align: center;
  font-size: 3rem;
}

.auth-title {
  text-align: center;
  font-size: var(--font-size-xl);
  font-weight: 800;
  margin-top: var(--space-2);
}

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

.form-group {
  margin-top: var(--space-4);
}

.form-label {
  display: block;
  font-weight: 700;
  font-size: var(--font-size-sm);
  margin-bottom: var(--space-2);
}

.form-input {
  width: 100%;
  min-height: 52px;
  padding: var(--space-3) var(--space-4);
  border-radius: var(--radius-md);
  border: 2px solid var(--color-border);
  font-family: var(--font-family);
  font-size: var(--font-size-md);
  background: var(--color-bg);
  color: var(--color-text);
  transition: border-color var(--duration-fast) ease;
}

.form-input:focus {
  outline: none;
  border-color: var(--color-primary);
}

.auth-switch {
  text-align: center;
  margin-top: var(--space-5);
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
}

.auth-switch a {
  color: var(--color-primary);
  font-weight: 700;
}

/* ---------- Level select ---------- */
.level-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-4);
  margin-top: var(--space-5);
}

@media (min-width: 600px) {
  .level-grid { grid-template-columns: repeat(4, 1fr); }
}

.level-card {
  text-align: center;
  padding: var(--space-5) var(--space-3);
}

.level-card .level-number {
  font-size: var(--font-size-2xl);
  font-weight: 800;
  color: var(--color-primary);
}

.level-card .level-name {
  margin-top: var(--space-1);
  font-weight: 700;
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
}

/* ---------- Question card (practice) ---------- */
.practice-page {
  max-width: 520px;
  margin-inline: auto;
  padding: var(--space-6) var(--space-4);
}

.practice-progress-row {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  margin-bottom: var(--space-5);
}

.practice-progress-row .progress { flex: 1; }

.practice-meta {
  font-weight: 700;
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  white-space: nowrap;
}

.question-card {
  text-align: center;
  padding: var(--space-7) var(--space-5);
}

.question-expression {
  font-size: var(--font-size-3xl);
  font-weight: 800;
  color: var(--color-text);
  letter-spacing: 2px;
}

.question-answer-input {
  margin-top: var(--space-6);
  text-align: center;
  font-size: var(--font-size-2xl);
  font-weight: 800;
  max-width: 180px;
  margin-inline: auto;
}

.question-feedback {
  margin-top: var(--space-5);
  border-radius: var(--radius-md);
  padding: var(--space-4);
  font-weight: 700;
  animation: alert-in var(--duration-base) var(--ease-bounce);
}

.question-feedback.is-correct {
  background: rgba(0, 184, 148, 0.14);
  color: #00795f;
}

.question-feedback.is-wrong {
  background: rgba(255, 118, 117, 0.14);
  color: #b8443f;
}

/* ---------- Result card ---------- */
.result-page {
  max-width: 480px;
  margin-inline: auto;
  padding: var(--space-6) var(--space-4);
  text-align: center;
}

.result-emoji {
  font-size: 4rem;
}

.result-stats {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-3);
  margin-top: var(--space-5);
}

.result-stat {
  padding: var(--space-4) var(--space-2);
}

.result-stat .stat-value {
  font-size: var(--font-size-xl);
  font-weight: 800;
  color: var(--color-primary);
}

.result-stat .stat-label {
  font-size: var(--font-size-xs);
  color: var(--color-text-muted);
  font-weight: 700;
  margin-top: var(--space-1);
}

.result-actions {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  margin-top: var(--space-6);
}

/* ---------- Toast (foundation only — wired up in a later phase) ---------- */
.toast {
  position: fixed;
  bottom: var(--space-5);
  left: 50%;
  transform: translateX(-50%);
  background: var(--color-text);
  color: var(--color-white);
  padding: var(--space-3) var(--space-5);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-lg);
  z-index: var(--z-toast);
}

/* ---------- Modal (foundation only) ---------- */
.modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(45, 42, 74, 0.45);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: var(--z-modal);
  padding: var(--space-4);
}

.modal {
  background: var(--color-white);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  padding: var(--space-6);
  max-width: 420px;
  width: 100%;
}

/* ---------- Practice Multiple Choice & Mascot (Phase 07) ---------- */
.practice-header-actions {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-3);
  margin-bottom: var(--space-4);
}

.practice-combo-badge {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  padding: var(--space-2) var(--space-4);
  border-radius: var(--radius-pill);
  font-weight: 800;
  font-size: var(--font-size-md);
  background: linear-gradient(135deg, #ff7675, #ff4757);
  color: #fff;
  box-shadow: 0 4px 12px rgba(255, 71, 87, 0.4);
  animation: pulse-combo 1.5s infinite;
}

@keyframes pulse-combo {
  0%, 100% { transform: scale(1); }
  50% { transform: scale(1.08); }
}

.practice-mascot-companion {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-3);
  margin: var(--space-4) auto var(--space-2) auto;
  max-width: 440px;
}

.practice-mascot-avatar {
  font-size: 3rem;
  line-height: 1;
  transition: transform var(--duration-fast) var(--ease-bounce);
  filter: drop-shadow(0 4px 6px rgba(0,0,0,0.1));
}

.practice-mascot-bubble {
  background: var(--color-white);
  border: 2px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: var(--space-2) var(--space-4);
  font-size: var(--font-size-sm);
  font-weight: 700;
  color: var(--color-text);
  box-shadow: var(--shadow-sm);
  position: relative;
  text-align: left;
}

.practice-options-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-4);
  margin-top: var(--space-6);
}

@media (max-width: 480px) {
  .practice-options-grid {
    grid-template-columns: 1fr;
    gap: var(--space-3);
  }
}

.practice-opt-card {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 72px;
  font-size: var(--font-size-2xl);
  font-weight: 800;
  border-radius: var(--radius-lg);
  border: 3px solid var(--color-border);
  background: var(--color-white);
  color: var(--color-text);
  box-shadow: 0 6px 0 var(--color-border);
  cursor: pointer;
  transition: transform var(--duration-fast) var(--ease-bounce),
              box-shadow var(--duration-fast) var(--ease-bounce),
              background var(--duration-fast);
  padding: var(--space-3) var(--space-4);
}

.practice-opt-card:hover:not(:disabled) {
  transform: translateY(-3px);
  border-color: var(--color-primary);
  box-shadow: 0 9px 0 var(--color-primary-dark, #4b44a4);
  color: var(--color-primary);
}

.practice-opt-card:active:not(:disabled) {
  transform: translateY(4px);
  box-shadow: 0 2px 0 var(--color-border);
}

.practice-opt-card .opt-key-hint {
  position: absolute;
  top: 6px;
  left: 10px;
  font-size: var(--font-size-xs);
  font-weight: 700;
  color: var(--color-text-muted);
  background: var(--color-bg-alt);
  padding: 2px 6px;
  border-radius: 4px;
}

.practice-opt-card.is-correct {
  background: #00b894 !important;
  color: #fff !important;
  border-color: #00a182 !important;
  box-shadow: 0 6px 0 #00795f !important;
  animation: bounce-card 0.5s ease;
}

.practice-opt-card.is-wrong {
  background: #ff7675 !important;
  color: #fff !important;
  border-color: #d63031 !important;
  box-shadow: 0 6px 0 #b8443f !important;
  animation: shake-card 0.4s ease;
}

@keyframes bounce-card {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-10px) scale(1.05); }
}

@keyframes shake-card {
  0%, 100% { transform: translateX(0); }
  20%, 60% { transform: translateX(-8px); }
  40%, 80% { transform: translateX(8px); }
}

.mascot-bounce {
  animation: bounce-card 0.6s ease;
}

.mascot-shake {
  animation: shake-card 0.5s ease;
}

/* ---------- Challenge Mode (Phase 09) ---------- */
.challenge-duration-option input {
  display: none;
}

.challenge-opt-box {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  background: var(--color-white);
  border: 2px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-4) var(--space-2);
  cursor: pointer;
  box-shadow: 0 4px 0 var(--color-border);
  transition: all var(--duration-fast) var(--ease-bounce);
  position: relative;
  text-align: center;
}

.challenge-duration-option input:checked + .challenge-opt-box {
  border-color: var(--color-primary);
  background: linear-gradient(180deg, #f4f3ff 0%, #ffffff 100%);
  box-shadow: 0 6px 0 var(--color-primary-dark);
  transform: translateY(-2px);
}

.challenge-opt-box .opt-time {
  font-weight: 800;
  font-size: var(--font-size-lg);
  color: var(--color-text);
}

.challenge-opt-box .opt-desc {
  font-size: var(--font-size-xs);
  color: var(--color-text-muted);
  margin-top: 4px;
}

.challenge-opt-box .opt-badge {
  position: absolute;
  top: -10px;
  background: #ff4757;
  color: #fff;
  font-size: 0.68rem;
  font-weight: 800;
  padding: 2px 8px;
  border-radius: var(--radius-pill);
}

.challenge-op-row {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-3);
  border-radius: var(--radius-md);
  border: 2px solid var(--color-border);
  background: var(--color-white);
  cursor: pointer;
  font-weight: 700;
  transition: border-color var(--duration-fast);
}

.challenge-op-row:hover {
  border-color: var(--color-primary);
}

.challenge-status-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-2);
  margin-bottom: var(--space-4);
}

.challenge-timer-badge {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  padding: var(--space-2) var(--space-4);
  border-radius: var(--radius-pill);
  font-weight: 800;
  font-size: var(--font-size-lg);
  background: #2d3436;
  color: #fff;
  box-shadow: 0 4px 10px rgba(0,0,0,0.15);
}

.challenge-timer-badge.timer-urgent {
  background: #d63031 !important;
  color: #fff !important;
  animation: urgent-pulse 0.7s infinite alternate;
}

@keyframes urgent-pulse {
  from { transform: scale(1); box-shadow: 0 0 10px rgba(214, 48, 49, 0.4); }
  to { transform: scale(1.1); box-shadow: 0 0 20px rgba(214, 48, 49, 0.9); }
}

/* 3-2-1 Countdown Overlay (Section 23) */
.challenge-countdown-overlay {
  position: fixed;
  inset: 0;
  background: rgba(45, 42, 74, 0.92);
  backdrop-filter: blur(8px);
  z-index: var(--z-modal);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: opacity 0.3s ease;
}

.challenge-countdown-box {
  text-align: center;
  color: #fff;
}

.challenge-countdown-mascot {
  font-size: 5rem;
  line-height: 1;
  margin-bottom: var(--space-3);
  animation: float 2s infinite ease-in-out;
}

.challenge-countdown-digit {
  font-family: var(--font-heading);
  font-size: 6rem;
  font-weight: 900;
  color: #ffd700;
  text-shadow: 0 6px 20px rgba(255, 215, 0, 0.6);
  line-height: 1;
  transition: transform 0.2s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

.challenge-countdown-hint {
  font-size: var(--font-size-lg);
  font-weight: 700;
  color: #dfe6e9;
  margin-top: var(--space-4);
}