/* ============================================================
   Memory Scramble — Design System & Styles sheet
   ============================================================ */

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

/* ---------- CSS Custom Properties ---------- */
:root {
  /* Palette — dark aurora theme */
  --bg-primary:    #0a0e1a;
  --bg-secondary:  #111827;
  --bg-card:       #1e293b;
  --bg-card-hover: #2d3a50;
  --surface:       rgba(255, 255, 255, 0.04);
  --surface-hover: rgba(255, 255, 255, 0.08);
  --border:        rgba(255, 255, 255, 0.08);
  --border-glow:   rgba(129, 140, 248, 0.35);

  --text-primary:   #f1f5f9;
  --text-secondary: #94a3b8;
  --text-muted:     #64748b;

  --accent:        #818cf8;
  --accent-light:  #a5b4fc;
  --accent-dark:   #6366f1;
  --success:       #34d399;
  --success-dark:  #059669;
  --danger:        #f87171;
  --danger-dark:   #dc2626;
  --warning:       #fbbf24;
  --info:          #38bdf8;

  /* Gradients */
  --gradient-accent: linear-gradient(135deg, #818cf8 0%, #c084fc 50%, #f472b6 100%);
  --gradient-card:   linear-gradient(145deg, rgba(129,140,248,.12) 0%, rgba(192,132,252,.08) 100%);
  --gradient-bg:     radial-gradient(ellipse at 20% 50%, rgba(99,102,241,.15) 0%, transparent 50%),
                     radial-gradient(ellipse at 80% 20%, rgba(192,132,252,.10) 0%, transparent 50%),
                     radial-gradient(ellipse at 50% 80%, rgba(244,114,182,.08) 0%, transparent 50%);

  /* Sizing */
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 20px;
  --radius-xl: 28px;

  /* Shadows */
  --shadow-sm: 0 2px 8px rgba(0,0,0,.25);
  --shadow-md: 0 4px 20px rgba(0,0,0,.35);
  --shadow-lg: 0 8px 40px rgba(0,0,0,.45);
  --shadow-glow: 0 0 20px rgba(129,140,248,.25);

  /* Transitions */
  --ease-out: cubic-bezier(.22,1,.36,1);
  --ease-spring: cubic-bezier(.34,1.56,.64,1);
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  font-family: 'Outfit', sans-serif;
  background: var(--bg-primary);
  color: var(--text-primary);
  min-height: 100vh;
  overflow-x: hidden;
  position: relative;
}

body::before {
  content: '';
  position: fixed;
  inset: 0;
  background: var(--gradient-bg);
  pointer-events: none;
  z-index: 0;
}

/* ---------- Layout ---------- */
#app {
  position: relative;
  z-index: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  min-height: 100vh;
  padding: 2rem 1rem;
}

/* ---------------- Header / Title --------------- */
.game-header {
  text-align: center;
  margin-bottom: 2rem;
}

.game-header h1 {
  font-size: 3rem;
  font-weight: 800;
  letter-spacing: -1px;
  background: var(--gradient-accent);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  margin-bottom: .25rem;
  animation: titlePulse 4s ease-in-out infinite alternate;
}

.game-header p {
  font-size: 1.05rem;
  color: var(--text-secondary);
  font-weight: 300;
}

@keyframes titlePulse {
  0%   { filter: brightness(1); }
  100% { filter: brightness(1.25); }
}

/* ----------------------- Config Panel ---------------------- */
.config-panel {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 2.5rem 3rem;
  max-width: 520px;
  width: 100%;
  box-shadow: var(--shadow-lg);
  animation: fadeSlideUp .6s var(--ease-out) both;
}

.config-panel h2 {
  font-size: 1.5rem;
  font-weight: 700;
  margin-bottom: 1.75rem;
  text-align: center;
  color: var(--accent-light);
}

.config-group {
  margin-bottom: 1.5rem;
}

.config-group label {
  display: block;
  font-size: .85rem;
  font-weight: 500;
  color: var(--text-secondary);
  margin-bottom: .5rem;
  text-transform: uppercase;
  letter-spacing: 1px;
}

.config-group input,
.config-group select {
  width: 100%;
  padding: .85rem 1rem;
  font-family: 'Outfit', sans-serif;
  font-size: 1rem;
  color: var(--text-primary);
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  outline: none;
  transition: border-color .3s, box-shadow .3s;
}

.config-group input:focus,
.config-group select:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(129,140,248,.2);
}

.config-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}

.config-error {
  color: var(--danger);
  font-size: .85rem;
  margin-top: .4rem;
  min-height: 1.2em;
}

/* --------------------------------- Buttons ----------------------------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: .5rem;
  padding: .85rem 2rem;
  font-family: 'Outfit', sans-serif;
  font-size: 1rem;
  font-weight: 600;
  border: none;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all .3s var(--ease-out);
  position: relative;
  overflow: hidden;
}

.btn::after {
  content: '';
  position: absolute;
  inset: 0;
  background: rgba(255,255,255,.1);
  opacity: 0;
  transition: opacity .3s;
}

.btn:hover::after {
  opacity: 1;
}

.btn:active {
  transform: scale(.97);
}

.btn-primary {
  background: var(--gradient-accent);
  color: #fff;
  box-shadow: 0 4px 20px rgba(129,140,248,.35);
}

.btn-primary:hover {
  box-shadow: 0 6px 30px rgba(129,140,248,.5);
  transform: translateY(-2px);
}

.btn-secondary {
  background: var(--surface);
  color: var(--text-primary);
  border: 1px solid var(--border);
}

.btn-secondary:hover {
  background: var(--surface-hover);
  border-color: var(--accent);
}

.btn-danger {
  background: linear-gradient(135deg, var(--danger) 0%, var(--danger-dark) 100%);
  color: #fff;
}

.btn-full {
  width: 100%;
  margin-top: .5rem;
}

/* ---------------------------- Game HUD ----------------------------- */
.game-hud {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 2rem;
  flex-wrap: wrap;
  margin-bottom: 2rem;
  animation: fadeSlideUp .5s var(--ease-out) both;
}

.hud-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: .75rem 1.5rem;
  min-width: 120px;
}

.hud-label {
  font-size: .7rem;
  font-weight: 500;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 1.5px;
  margin-bottom: .25rem;
}

.hud-value {
  font-size: 1.75rem;
  font-weight: 700;
  color: var(--text-primary);
  font-variant-numeric: tabular-nums;
}

.hud-value.timer {
  color: var(--accent-light);
}

.hud-value.timer.danger {
  color: var(--danger);
  animation: pulse .6s ease-in-out infinite alternate;
}

@keyframes pulse {
  from { opacity: 1; }
  to   { opacity: .5; }
}

.hud-actions {
  display: flex;
  gap: .75rem;
}

/* -------------------------------- Game Board ---------------------------- */
.game-board {
  display: grid;
  gap: 12px;
  justify-content: center;
  padding: 1.5rem;
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-lg);
  animation: fadeSlideUp .6s var(--ease-out) .15s both;
}

/* ----------------------------- Card ------------------------------- */
.card {
  width: 90px;
  height: 110px;
  perspective: 800px;
  cursor: pointer;
}

.card-inner {
  position: relative;
  width: 100%;
  height: 100%;
  transition: transform .55s var(--ease-spring);
  transform-style: preserve-3d;
}

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

.card-face {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-md);
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
  border: 2px solid transparent;
  transition: border-color .3s, box-shadow .3s;
}

/* Back (face-down) */
.card-back {
  background: var(--gradient-card);
  border-color: var(--border);
  backdrop-filter: blur(8px);
}

.card-back::before {
  content: '?';
  font-size: 2rem;
  font-weight: 700;
  color: var(--accent);
  opacity: .4;
}

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

/* Front (face-up) */
.card-front {
  transform: rotateY(180deg);
  background: var(--bg-card);
  border-color: var(--border);
}

.card-front .card-icon {
  font-size: 2.6rem;
  line-height: 1;
  user-select: none;
}

/* Matched state */
.card.matched .card-front {
  border-color: var(--success);
  box-shadow: 0 0 18px rgba(52,211,153,.3);
  background: linear-gradient(145deg, rgba(52,211,153,.08), var(--bg-card));
}

.card.matched {
  cursor: default;
  animation: matchBounce .5s var(--ease-spring);
}

@keyframes matchBounce {
  0%   { transform: scale(1); }
  40%  { transform: scale(1.12); }
  100% { transform: scale(1); }
}

/* Mismatch shake */
.card.mismatch .card-front {
  border-color: var(--danger);
  box-shadow: 0 0 14px rgba(248,113,113,.25);
}

.card.mismatch {
  animation: shake .45s ease;
}

@keyframes shake {
  0%, 100% { transform: translateX(0); }
  20%      { transform: translateX(-6px); }
  40%      { transform: translateX(6px); }
  60%      { transform: translateX(-4px); }
  80%      { transform: translateX(4px); }
}

/* ---------- Overlays / Modals ---------- */
.overlay {
  position: fixed;
  inset: 0;
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(10, 14, 26, .85);
  backdrop-filter: blur(8px);
  animation: fadeIn .35s ease both;
}

.modal {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius-xl);
  padding: 3rem 3.5rem;
  text-align: center;
  max-width: 440px;
  width: 90%;
  box-shadow: var(--shadow-lg);
  animation: modalPop .45s var(--ease-spring) both;
}

.modal h2 {
  font-size: 2rem;
  font-weight: 800;
  margin-bottom: .75rem;
}

.modal p {
  color: var(--text-secondary);
  margin-bottom: 1.5rem;
  line-height: 1.6;
}

.modal .btn {
  margin: .35rem;
}

.modal-icon {
  font-size: 4rem;
  margin-bottom: 1rem;
  display: block;
}

.modal-win h2  { color: var(--success); }
.modal-lose h2 { color: var(--danger); }

.stats-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: .75rem;
  margin-bottom: 1.5rem;
}

.stat-item {
  background: var(--surface);
  border-radius: var(--radius-sm);
  padding: .65rem .5rem;
}

.stat-label {
  font-size: .7rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 1px;
}

.stat-value {
  font-size: 1.3rem;
  font-weight: 700;
  color: var(--text-primary);
}

/* ---------- Animations ---------- */
@keyframes fadeIn {
  from { opacity: 0; }
  to   { opacity: 1; }
}

@keyframes fadeSlideUp {
  from {
    opacity: 0;
    transform: translateY(24px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes modalPop {
  from {
    opacity: 0;
    transform: scale(.85) translateY(20px);
  }
  to {
    opacity: 1;
    transform: scale(1) translateY(0);
  }
}

/* ---------- Responsive ---------- */
@media (max-width: 640px) {
  .game-header h1 { font-size: 2rem; }
  .config-panel { padding: 1.5rem; }
  .config-row { grid-template-columns: 1fr; }
  .card { width: 65px; height: 80px; }
  .card-front .card-icon { font-size: 1.8rem; }
  .card-back::before { font-size: 1.4rem; }
  .game-board { gap: 8px; padding: 1rem; }
  .hud-item { min-width: 90px; padding: .6rem 1rem; }
  .hud-value { font-size: 1.3rem; }
  .modal { padding: 2rem 1.5rem; }
}

@media (max-width: 420px) {
  .card { width: 52px; height: 66px; }
  .card-front .card-icon { font-size: 1.4rem; }
  .game-board { gap: 6px; padding: .75rem; }
  .game-hud { gap: 1rem; }
}

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

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

.mt-1 { margin-top: 1rem; }
.mt-2 { margin-top: 2rem; }