/* ============================================================
   CapiQuiz – Capital City Flashcard App
   CSS Design System
   SDLC Phase: Design → Implementation
   ============================================================ */

/* ── Google Font + CSS Variables ── */
@import url('https://fonts.googleapis.com/css2?family=Outfit:wght@300;400;500;600;700;800&display=swap');

:root {
  --bg-primary:    #0d0f1a;
  --bg-secondary:  #131629;
  --bg-card:       #1a1e35;
  --bg-card-back:  #1c2a45;
  --accent:        #6c63ff;
  --accent-2:      #00d4ff;
  --accent-glow:   rgba(108, 99, 255, 0.35);
  --success:       #00e676;
  --danger:        #ff5252;
  --warning:       #ffab40;
  --text-primary:  #f0f2ff;
  --text-secondary:#9ba5cc;
  --text-muted:    #5a6180;
  --border:        rgba(255,255,255,0.08);
  --border-hover:  rgba(108,99,255,0.5);
  --radius-sm:     8px;
  --radius-md:     16px;
  --radius-lg:     24px;
  --radius-xl:     32px;
  --shadow-card:   0 20px 60px rgba(0,0,0,0.5);
  --shadow-glow:   0 0 40px rgba(108,99,255,0.3);
  --font:          'Outfit', sans-serif;
  --transition:    all 0.3s cubic-bezier(0.4,0,0.2,1);
}

/* ── Reset ── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }

body {
  font-family: var(--font);
  background: var(--bg-primary);
  color: var(--text-primary);
  min-height: 100vh;
  overflow-x: hidden;
  background-image:
    radial-gradient(ellipse 80% 50% at 50% -20%, rgba(108,99,255,0.15) 0%, transparent 70%),
    radial-gradient(ellipse 60% 40% at 80% 80%, rgba(0,212,255,0.08) 0%, transparent 60%);
}

/* ── Utility ── */
.hidden { display: none !important; }

/* ================================================================
   LOADING SCREEN
   ================================================================ */
.loading-screen {
  position: fixed; inset: 0;
  background: var(--bg-primary);
  display: flex; align-items: center; justify-content: center;
  z-index: 9999;
  flex-direction: column;
  gap: 1rem;
  transition: opacity 0.5s ease, visibility 0.5s ease;
}

.loader-content {
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 1rem;
}

.globe-spinner {
  font-size: 5rem;
  animation: spin-globe 2s linear infinite;
  display: block;
}

@keyframes spin-globe {
  from { transform: rotate(0deg) scale(1); }
  50%  { transform: rotate(180deg) scale(1.1); }
  to   { transform: rotate(360deg) scale(1); }
}

.loader-content h2 {
  font-size: 1.6rem;
  font-weight: 700;
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.loader-content p {
  color: var(--text-secondary);
  font-size: 0.95rem;
}

.progress-bar-loader {
  width: 240px;
  height: 6px;
  background: var(--bg-card);
  border-radius: 100px;
  overflow: hidden;
}

.progress-fill-loader {
  height: 100%;
  background: linear-gradient(90deg, var(--accent), var(--accent-2));
  border-radius: 100px;
  width: 0%;
  transition: width 0.3s ease;
  animation: load-progress 2.5s ease-in-out forwards;
}

@keyframes load-progress {
  0%   { width: 0%; }
  30%  { width: 40%; }
  60%  { width: 70%; }
  90%  { width: 90%; }
  100% { width: 100%; }
}

/* ================================================================
   APP LAYOUT
   ================================================================ */
.app {
  max-width: 900px;
  margin: 0 auto;
  padding: 1rem;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

/* ================================================================
   HEADER
   ================================================================ */
.header {
  background: rgba(26, 30, 53, 0.7);
  backdrop-filter: blur(20px);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 1rem 1.5rem;
  position: sticky;
  top: 1rem;
  z-index: 100;
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 1rem;
}

.logo {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.logo-icon { font-size: 1.8rem; }

.logo-text {
  font-size: 1.5rem;
  font-weight: 800;
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.header-stats {
  display: flex;
  gap: 0.6rem;
  flex-wrap: wrap;
}

.stat-chip {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  background: rgba(108,99,255,0.1);
  border: 1px solid rgba(108,99,255,0.25);
  border-radius: 100px;
  padding: 0.35rem 0.85rem;
  font-size: 0.88rem;
  color: var(--text-secondary);
  transition: var(--transition);
}

.stat-chip strong { color: var(--text-primary); }
.stat-chip .stat-icon { font-size: 1rem; }

#stat-score { border-color: rgba(255,171,64,0.4); background: rgba(255,171,64,0.08); }
#stat-streak { border-color: rgba(255,82,82,0.4); background: rgba(255,82,82,0.08); }

/* ================================================================
   CONTROLS
   ================================================================ */
.controls-section {
  background: rgba(26, 30, 53, 0.5);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 1rem 1.5rem;
}

.controls-inner {
  display: flex;
  align-items: center;
  gap: 1rem;
  flex-wrap: wrap;
}

/* Mode Toggle */
.mode-toggle {
  display: flex;
  background: var(--bg-primary);
  border-radius: var(--radius-sm);
  padding: 4px;
  gap: 4px;
  border: 1px solid var(--border);
}

.mode-btn {
  padding: 0.5rem 1.1rem;
  border: none;
  border-radius: 6px;
  font-family: var(--font);
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  background: transparent;
  color: var(--text-secondary);
  transition: var(--transition);
}

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

.mode-btn.active {
  background: linear-gradient(135deg, var(--accent), #857bff);
  color: #fff;
  box-shadow: 0 4px 15px rgba(108,99,255,0.4);
}

/* Filters */
.filter-group {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.9rem;
  color: var(--text-secondary);
}

.filter-group select {
  background: var(--bg-card);
  border: 1px solid var(--border);
  color: var(--text-primary);
  border-radius: var(--radius-sm);
  padding: 0.45rem 0.8rem;
  font-family: var(--font);
  font-size: 0.88rem;
  cursor: pointer;
  outline: none;
  transition: var(--transition);
}

.filter-group select:hover,
.filter-group select:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-glow);
}

.btn-reset {
  margin-left: auto;
  padding: 0.5rem 1.1rem;
  background: rgba(255,82,82,0.12);
  border: 1px solid rgba(255,82,82,0.3);
  color: #ff7676;
  border-radius: var(--radius-sm);
  font-family: var(--font);
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition);
}

.btn-reset:hover {
  background: rgba(255,82,82,0.22);
  border-color: #ff5252;
}

/* ================================================================
   PROGRESS
   ================================================================ */
.progress-section {
  padding: 0 0.25rem;
}

.progress-info {
  display: flex;
  justify-content: space-between;
  font-size: 0.85rem;
  color: var(--text-secondary);
  margin-bottom: 0.4rem;
}

.progress-bar {
  height: 6px;
  background: var(--bg-card);
  border-radius: 100px;
  overflow: hidden;
}

.progress-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--accent), var(--accent-2));
  border-radius: 100px;
  transition: width 0.5s cubic-bezier(0.4,0,0.2,1);
  position: relative;
}

.progress-fill::after {
  content: '';
  position: absolute;
  right: 0; top: 0; bottom: 0;
  width: 30px;
  background: linear-gradient(90deg, transparent, rgba(255,255,255,0.3));
  border-radius: 100px;
  animation: shimmer 1.5s ease infinite;
}

@keyframes shimmer {
  0%   { opacity: 0; }
  50%  { opacity: 1; }
  100% { opacity: 0; }
}

/* ================================================================
   FLASHCARD MODE
   ================================================================ */
.mode-section { flex: 1; }

.card-container {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 1.5rem;
  padding: 1rem 0;
}

/* 3D Card */
.flashcard {
  width: 100%;
  max-width: 520px;
  height: 340px;
  perspective: 1200px;
  cursor: pointer;
  user-select: none;
}

.card-inner {
  width: 100%;
  height: 100%;
  position: relative;
  transform-style: preserve-3d;
  transition: transform 0.65s cubic-bezier(0.4, 0, 0.2, 1);
}

.card-inner.flipped { transform: rotateY(180deg); }

.card-front,
.card-back {
  position: absolute;
  inset: 0;
  border-radius: var(--radius-xl);
  padding: 2rem;
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 0.8rem;
  border: 1px solid var(--border);
  transition: var(--transition);
}

.card-front {
  background: linear-gradient(145deg, var(--bg-card), #1e2440);
  box-shadow: var(--shadow-card), inset 0 1px 0 rgba(255,255,255,0.05);
}

.card-front:hover {
  border-color: var(--border-hover);
  box-shadow: var(--shadow-card), var(--shadow-glow);
}

.card-back {
  background: linear-gradient(145deg, var(--bg-card-back), #1a2c4a);
  transform: rotateY(180deg);
  box-shadow: var(--shadow-card), 0 0 40px rgba(0,212,255,0.2);
  border-color: rgba(0,212,255,0.2);
}

.card-hint {
  font-size: 0.78rem;
  color: var(--text-muted);
  letter-spacing: 0.1em;
  text-transform: uppercase;
  font-weight: 600;
}

.flag-display {
  font-size: 4.5rem;
  line-height: 1;
  filter: drop-shadow(0 4px 12px rgba(0,0,0,0.4));
  transition: transform 0.3s ease;
}

.flag-display:hover { transform: scale(1.05); }

.flag-display img {
  width: 90px;
  height: 60px;
  object-fit: cover;
  border-radius: 6px;
  box-shadow: 0 4px 16px rgba(0,0,0,0.4);
}

.country-name {
  font-size: 2rem;
  font-weight: 800;
  text-align: center;
  color: var(--text-primary);
  line-height: 1.2;
}

.region-badge {
  font-size: 0.8rem;
  padding: 0.3rem 0.8rem;
  background: rgba(108,99,255,0.15);
  border: 1px solid rgba(108,99,255,0.3);
  border-radius: 100px;
  color: #a09bff;
  font-weight: 600;
}

.card-prompt {
  font-size: 0.95rem;
  color: var(--text-secondary);
  margin-top: 0.3rem;
}

/* Card Back */
.capital-answer {
  font-size: 2.3rem;
  font-weight: 800;
  background: linear-gradient(135deg, #00d4ff, #80eaff);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  text-align: center;
}

.country-name-back {
  color: var(--text-secondary);
  font-size: 1rem;
}

.card-actions {
  display: flex;
  gap: 0.8rem;
  margin-top: 0.5rem;
}

.btn-knew, .btn-missed {
  padding: 0.6rem 1.4rem;
  border: none;
  border-radius: var(--radius-sm);
  font-family: var(--font);
  font-size: 0.95rem;
  font-weight: 700;
  cursor: pointer;
  transition: var(--transition);
}

.btn-knew {
  background: linear-gradient(135deg, #00e676, #00c853);
  color: #001a0a;
  box-shadow: 0 4px 15px rgba(0,230,118,0.3);
}

.btn-knew:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 25px rgba(0,230,118,0.5);
}

.btn-missed {
  background: linear-gradient(135deg, #ff5252, #d32f2f);
  color: #fff;
  box-shadow: 0 4px 15px rgba(255,82,82,0.3);
}

.btn-missed:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 25px rgba(255,82,82,0.5);
}

/* Card Nav */
.card-nav {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.btn-nav {
  padding: 0.6rem 1.3rem;
  background: rgba(108,99,255,0.12);
  border: 1px solid rgba(108,99,255,0.3);
  color: #a09bff;
  border-radius: var(--radius-sm);
  font-family: var(--font);
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition);
}

.btn-nav:hover {
  background: rgba(108,99,255,0.22);
  color: #fff;
  transform: translateY(-1px);
}

.btn-nav:disabled {
  opacity: 0.3;
  cursor: not-allowed;
  transform: none;
}

.dot-indicators {
  display: flex;
  gap: 5px;
  flex-wrap: wrap;
  justify-content: center;
  max-width: 200px;
}

.dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--text-muted);
  transition: var(--transition);
}

.dot.active {
  background: var(--accent);
  box-shadow: 0 0 8px var(--accent);
  transform: scale(1.3);
}

.dot.correct { background: var(--success); }
.dot.missed  { background: var(--danger); }

/* ================================================================
   QUIZ MODE
   ================================================================ */
.quiz-container {
  display: flex;
  justify-content: center;
  padding: 1rem 0;
}

.quiz-card {
  width: 100%;
  max-width: 580px;
  background: linear-gradient(145deg, var(--bg-card), #1e2440);
  border: 1px solid var(--border);
  border-radius: var(--radius-xl);
  padding: 2rem;
  box-shadow: var(--shadow-card);
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.quiz-header {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.7rem;
}

.flag-display-quiz {
  font-size: 5rem;
  line-height: 1;
}

.flag-display-quiz img {
  width: 110px;
  height: 72px;
  object-fit: cover;
  border-radius: 8px;
  box-shadow: 0 4px 20px rgba(0,0,0,0.5);
}

.quiz-country {
  font-size: 2rem;
  font-weight: 800;
  text-align: center;
}

.quiz-question {
  color: var(--text-secondary);
  font-size: 1rem;
}

/* Options Grid */
.quiz-options {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.75rem;
}

.quiz-opt {
  padding: 0.9rem 1.1rem;
  background: rgba(255,255,255,0.04);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  font-family: var(--font);
  font-size: 0.95rem;
  font-weight: 500;
  cursor: pointer;
  transition: var(--transition);
  text-align: center;
}

.quiz-opt:hover:not(:disabled) {
  background: rgba(108,99,255,0.15);
  border-color: var(--accent);
  transform: translateY(-2px);
  box-shadow: 0 4px 15px rgba(108,99,255,0.2);
}

.quiz-opt.correct {
  background: rgba(0,230,118,0.15);
  border-color: var(--success);
  color: var(--success);
  font-weight: 700;
}

.quiz-opt.wrong {
  background: rgba(255,82,82,0.12);
  border-color: var(--danger);
  color: var(--danger);
  font-weight: 700;
}

.quiz-opt:disabled { cursor: not-allowed; }

/* Feedback */
.quiz-feedback {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  font-size: 1.1rem;
  font-weight: 700;
  padding: 0.75rem 1.5rem;
  border-radius: var(--radius-md);
  animation: pop-in 0.3s cubic-bezier(0.34,1.56,0.64,1);
}

.quiz-feedback.correct-fb {
  background: rgba(0,230,118,0.12);
  border: 1px solid rgba(0,230,118,0.3);
  color: var(--success);
}

.quiz-feedback.wrong-fb {
  background: rgba(255,82,82,0.12);
  border: 1px solid rgba(255,82,82,0.3);
  color: var(--danger);
}

@keyframes pop-in {
  from { transform: scale(0.8); opacity: 0; }
  to   { transform: scale(1);   opacity: 1; }
}

.btn-next-quiz {
  width: 100%;
  padding: 0.9rem;
  background: linear-gradient(135deg, var(--accent), #857bff);
  border: none;
  border-radius: var(--radius-md);
  color: #fff;
  font-family: var(--font);
  font-size: 1rem;
  font-weight: 700;
  cursor: pointer;
  transition: var(--transition);
  box-shadow: 0 4px 20px rgba(108,99,255,0.4);
}

.btn-next-quiz:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 30px rgba(108,99,255,0.6);
}

/* ================================================================
   RESULTS OVERLAY
   ================================================================ */
.results-overlay {
  position: fixed; inset: 0;
  background: rgba(0,0,0,0.75);
  backdrop-filter: blur(10px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 500;
  padding: 1rem;
}

.results-card {
  background: linear-gradient(145deg, var(--bg-card), #1a2240);
  border: 1px solid rgba(108,99,255,0.3);
  border-radius: var(--radius-xl);
  padding: 2.5rem 2rem;
  max-width: 460px;
  width: 100%;
  text-align: center;
  box-shadow: 0 30px 80px rgba(0,0,0,0.6), var(--shadow-glow);
  animation: slide-up 0.4s cubic-bezier(0.34,1.56,0.64,1);
}

@keyframes slide-up {
  from { transform: translateY(40px) scale(0.95); opacity: 0; }
  to   { transform: translateY(0) scale(1);       opacity: 1; }
}

.results-emoji { font-size: 4rem; margin-bottom: 0.5rem; }

.results-card h2 {
  font-size: 1.9rem;
  font-weight: 800;
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin-bottom: 0.3rem;
}

.results-card p { color: var(--text-secondary); margin-bottom: 1.5rem; }

.results-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1rem;
  margin-bottom: 1.5rem;
}

.result-item {
  background: rgba(108,99,255,0.1);
  border: 1px solid rgba(108,99,255,0.2);
  border-radius: var(--radius-md);
  padding: 1rem;
  display: flex;
  flex-direction: column;
  gap: 0.3rem;
}

.result-num {
  font-size: 2rem;
  font-weight: 800;
  color: var(--accent-2);
}

.result-label {
  font-size: 0.82rem;
  color: var(--text-secondary);
  font-weight: 500;
}

.results-actions {
  display: flex;
  gap: 0.75rem;
}

.btn-play-again, .btn-change-region {
  flex: 1;
  padding: 0.85rem;
  border: none;
  border-radius: var(--radius-md);
  font-family: var(--font);
  font-size: 0.95rem;
  font-weight: 700;
  cursor: pointer;
  transition: var(--transition);
}

.btn-play-again {
  background: linear-gradient(135deg, var(--accent), #857bff);
  color: #fff;
  box-shadow: 0 4px 20px rgba(108,99,255,0.4);
}

.btn-play-again:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 30px rgba(108,99,255,0.6);
}

.btn-change-region {
  background: rgba(255,255,255,0.06);
  border: 1px solid var(--border);
  color: var(--text-primary);
}

.btn-change-region:hover {
  background: rgba(255,255,255,0.1);
}

/* ================================================================
   CONFETTI
   ================================================================ */
#confetti-canvas {
  position: fixed;
  top: 0; left: 0;
  width: 100%; height: 100%;
  pointer-events: none;
  z-index: 1000;
}

/* ================================================================
   FOOTER
   ================================================================ */
.footer {
  text-align: center;
  color: var(--text-muted);
  font-size: 0.82rem;
  padding: 0.5rem 0 1rem;
}

.footer a {
  color: #6c63ff;
  text-decoration: none;
}

.footer a:hover { text-decoration: underline; }

/* ================================================================
   CARD ENTRANCE ANIMATION
   ================================================================ */
@keyframes card-enter {
  from { opacity: 0; transform: translateY(20px) scale(0.97); }
  to   { opacity: 1; transform: translateY(0) scale(1); }
}

.card-enter {
  animation: card-enter 0.4s cubic-bezier(0.34,1.2,0.64,1);
}

/* Pulse animation for score update */
@keyframes score-pulse {
  0%   { transform: scale(1); }
  50%  { transform: scale(1.3); }
  100% { transform: scale(1); }
}

.score-pulse { animation: score-pulse 0.4s ease; }

/* ================================================================
   RESPONSIVE
   ================================================================ */
@media (max-width: 600px) {
  .flashcard { height: 300px; }
  .country-name { font-size: 1.5rem; }
  .capital-answer { font-size: 1.8rem; }
  .quiz-options { grid-template-columns: 1fr; }
  .header-stats { gap: 0.4rem; }
  .stat-chip { font-size: 0.78rem; padding: 0.3rem 0.65rem; }
  .controls-inner { gap: 0.6rem; }
  .results-grid { grid-template-columns: 1fr 1fr; }
  .card-nav { flex-wrap: wrap; justify-content: center; }
}

@media (max-width: 400px) {
  .app { padding: 0.5rem; }
  .card-front, .card-back { padding: 1.2rem; }
  .quiz-card { padding: 1.2rem; }
}