/* Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-color: #6366f1;
    --primary-hover: #4f46e5;
    --success-color: #22c55e;
    --danger-color: #ef4444;
    --bg-color: #0f172a;
    --card-bg: #1e293b;
    --text-color: #f8fafc;
    --text-muted: #94a3b8;
    --card-back: #3b82f6;
    --player1-color: #f59e0b;
    --player2-color: #ec4899;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: var(--bg-color);
    color: var(--text-color);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    overflow: hidden;
}

/* Sparkle background */
body::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    background-image:
        radial-gradient(2px 2px at 20px 30px, rgba(255,255,255,0.8), transparent),
        radial-gradient(2px 2px at 40px 70px, rgba(255,255,255,0.6), transparent),
        radial-gradient(1px 1px at 90px 40px, rgba(255,255,255,0.9), transparent),
        radial-gradient(2px 2px at 130px 80px, rgba(255,255,255,0.5), transparent),
        radial-gradient(1px 1px at 160px 120px, rgba(255,255,255,0.7), transparent),
        radial-gradient(2px 2px at 200px 50px, rgba(255,255,255,0.6), transparent),
        radial-gradient(1px 1px at 250px 160px, rgba(255,255,255,0.8), transparent),
        radial-gradient(2px 2px at 300px 90px, rgba(255,255,255,0.5), transparent),
        radial-gradient(1px 1px at 350px 200px, rgba(255,255,255,0.9), transparent),
        radial-gradient(2px 2px at 400px 150px, rgba(255,255,255,0.6), transparent);
    background-size: 400px 250px;
    animation: sparkle-bg 4s ease-in-out infinite;
    z-index: 0;
}

@keyframes sparkle-bg {
    0%, 100% { opacity: 0.3; transform: scale(1); }
    50% { opacity: 0.7; transform: scale(1.02); }
}

.container {
    position: relative;
    z-index: 1;
    width: 100%;
    max-width: 800px;
    padding: 20px;
}

/* Screen Management */
.screen {
    display: none;
}

.screen.active {
    display: block;
}

/* Start Screen */
#start-screen {
    text-align: center;
}

#start-screen h1 {
    font-size: 3rem;
    margin-bottom: 2rem;
    background: linear-gradient(135deg, var(--primary-color), var(--player2-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.menu {
    background: var(--card-bg);
    padding: 2rem;
    border-radius: 16px;
    max-width: 400px;
    margin: 0 auto;
}

.setting {
    margin-bottom: 1.5rem;
    text-align: left;
}

.setting label {
    display: block;
    margin-bottom: 0.5rem;
    color: var(--text-muted);
    font-size: 0.9rem;
}

.setting select {
    width: 100%;
    padding: 12px;
    border: none;
    border-radius: 8px;
    background: var(--bg-color);
    color: var(--text-color);
    font-size: 1rem;
    cursor: pointer;
}

.player-names {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
    margin-bottom: 1.5rem;
}

.player-names input {
    padding: 12px;
    border: none;
    border-radius: 8px;
    background: var(--bg-color);
    color: var(--text-color);
    font-size: 1rem;
}

.player-names input::placeholder {
    color: var(--text-muted);
}

.hidden {
    display: none !important;
}

/* Buttons */
.btn {
    padding: 14px 28px;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: transform 0.15s, background 0.15s;
    background: var(--card-bg);
    color: var(--text-color);
}

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

.btn:active {
    transform: translateY(0);
}

.btn-primary {
    background: var(--primary-color);
    color: white;
    width: 100%;
}

.btn-primary:hover {
    background: var(--primary-hover);
}

.btn-small {
    padding: 8px 16px;
    font-size: 0.85rem;
}

/* Game Header */
.game-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
    flex-wrap: wrap;
    gap: 1rem;
}

.score-panel {
    display: flex;
    gap: 1rem;
}

.player-score {
    background: var(--card-bg);
    padding: 10px 20px;
    border-radius: 8px;
    text-align: center;
    opacity: 0.5;
    transition: opacity 0.3s, box-shadow 0.3s;
}

.player-score.active {
    opacity: 1;
}

#player1-panel.active {
    box-shadow: 0 0 0 2px var(--player1-color);
}

#player2-panel.active {
    box-shadow: 0 0 0 2px var(--player2-color);
}

.player-score .player-name {
    display: block;
    font-size: 0.8rem;
    color: var(--text-muted);
    margin-bottom: 4px;
}

.player-score .score {
    font-size: 1.5rem;
    font-weight: bold;
}

#player1-panel .score {
    color: var(--player1-color);
}

#player2-panel .score {
    color: var(--player2-color);
}

.game-info {
    display: flex;
    gap: 1.5rem;
    color: var(--text-muted);
}

#misses-count {
    color: var(--danger-color);
    font-weight: bold;
}

#matches-count {
    color: var(--success-color);
    font-weight: bold;
}

/* Game Board */
.game-board {
    display: grid;
    gap: 10px;
    justify-content: center;
    perspective: 1000px;
}

.game-board.grid-3x4 {
    grid-template-columns: repeat(4, 1fr);
    max-width: 440px;
    margin: 0 auto;
}

.game-board.grid-4x4 {
    grid-template-columns: repeat(4, 1fr);
    max-width: 440px;
    margin: 0 auto;
}

.game-board.grid-5x4 {
    grid-template-columns: repeat(5, 1fr);
    max-width: 550px;
    margin: 0 auto;
}

.game-board.grid-4x5 {
    grid-template-columns: repeat(4, 1fr);
    max-width: 440px;
    margin: 0 auto;
}

/* Cards */
.card {
    aspect-ratio: 1;
    cursor: pointer;
    position: relative;
    transform-style: preserve-3d;
    transition: transform 0.5s;
}

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

.card.matched {
    cursor: default;
}

.card.matched .card-front {
    background: var(--success-color);
    box-shadow: 0 0 20px rgba(34, 197, 94, 0.4);
    overflow: hidden;
}

/* Matched card celebration shimmer - plays once then stops */
.card.matched.celebrate .card-front::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 200%;
    height: 100%;
    background: linear-gradient(
        90deg,
        transparent,
        rgba(255, 255, 255, 0.6),
        transparent
    );
    animation: shimmer 0.6s ease-out forwards;
}

@keyframes shimmer {
    0% { left: -100%; }
    100% { left: 100%; }
}

.card-face {
    position: absolute;
    width: 100%;
    height: 100%;
    backface-visibility: hidden;
    border-radius: 12px;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 2.5rem;
}

.card-back {
    background: linear-gradient(135deg, var(--card-back), var(--primary-color));
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.3);
    overflow: hidden;
}

/* Card sparkle overlay */
.card-back::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-image:
        radial-gradient(2px 2px at 15% 20%, rgba(255,255,255,0.9), transparent),
        radial-gradient(1px 1px at 35% 60%, rgba(255,255,255,0.7), transparent),
        radial-gradient(2px 2px at 55% 30%, rgba(255,255,255,0.8), transparent),
        radial-gradient(1px 1px at 75% 70%, rgba(255,255,255,0.6), transparent),
        radial-gradient(2px 2px at 85% 15%, rgba(255,255,255,0.9), transparent),
        radial-gradient(1px 1px at 25% 85%, rgba(255,255,255,0.7), transparent),
        radial-gradient(2px 2px at 65% 90%, rgba(255,255,255,0.8), transparent),
        radial-gradient(1px 1px at 45% 45%, rgba(255,255,255,0.6), transparent);
    animation: card-sparkle 2s ease-in-out infinite;
    border-radius: 12px;
}

@keyframes card-sparkle {
    0%, 100% { opacity: 0.4; }
    50% { opacity: 1; }
}

.card-back::after {
    content: '?';
    color: rgba(255, 255, 255, 0.3);
    font-size: 2rem;
    font-weight: bold;
    position: relative;
    z-index: 1;
}

.card-front {
    background: var(--card-bg);
    transform: rotateY(180deg);
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.3);
}

/* Card shake animation for wrong match */
@keyframes shake {
    0%, 100% { transform: rotateY(180deg) translateX(0); }
    25% { transform: rotateY(180deg) translateX(-5px); }
    75% { transform: rotateY(180deg) translateX(5px); }
}

.card.wrong {
    animation: shake 0.3s ease-in-out;
}

.card.wrong .card-front {
    background: var(--danger-color);
}

/* Game Over Screen */
#gameover-screen {
    text-align: center;
}

#gameover-screen h2 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.gameover-message {
    font-size: 1.25rem;
    color: var(--text-muted);
    margin-bottom: 2rem;
}

.gameover-stats {
    background: var(--card-bg);
    padding: 1.5rem;
    border-radius: 12px;
    margin-bottom: 2rem;
    display: inline-block;
}

.gameover-stats p {
    margin: 0.5rem 0;
    font-size: 1.1rem;
}

.gameover-stats span {
    font-weight: bold;
    color: var(--primary-color);
}

.gameover-buttons {
    display: flex;
    gap: 1rem;
    justify-content: center;
}

/* Win animation */
.win-title {
    color: var(--success-color);
}

.lose-title {
    color: var(--danger-color);
}

/* Responsive */
@media (max-width: 600px) {
    .container {
        padding: 10px;
    }

    #start-screen h1 {
        font-size: 2rem;
    }

    .game-header {
        flex-direction: column;
        align-items: stretch;
        text-align: center;
    }

    .score-panel {
        justify-content: center;
    }

    .game-info {
        justify-content: center;
    }

    .card-face {
        font-size: 1.8rem;
    }

    .game-board {
        gap: 6px;
    }

    .gameover-buttons {
        flex-direction: column;
    }

    .gameover-buttons .btn {
        width: 100%;
    }
}