:root {
    --bg-color: #0f172a; /* Dark slate */
    --surface-color: rgba(30, 41, 59, 0.7);
    --border-color: rgba(255, 255, 255, 0.1);
    --text-main: #f8fafc;
    --text-muted: #94a3b8;
    
    --x-color: #38bdf8; /* Light blue */
    --x-glow: rgba(56, 189, 248, 0.5);
    
    --o-color: #f472b6; /* Pink */
    --o-glow: rgba(244, 114, 182, 0.5);
    
    --win-bg: rgba(52, 211, 153, 0.2);
    --win-color: #34d399;
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    font-family: 'Outfit', sans-serif;
    background-color: var(--bg-color);
    background-image: 
        radial-gradient(at 0% 0%, rgba(56, 189, 248, 0.15) 0px, transparent 50%),
        radial-gradient(at 100% 100%, rgba(244, 114, 182, 0.15) 0px, transparent 50%);
    color: var(--text-main);
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    padding: 20px;
    overflow-x: hidden;
}

.container {
    width: 100%;
    max-width: 450px;
    display: flex;
    flex-direction: column;
    gap: 2rem;
}

header {
    text-align: center;
}

h1 {
    font-size: 2.5rem;
    font-weight: 800;
    background: linear-gradient(to right, var(--x-color), var(--o-color));
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
    margin-bottom: 0.25rem;
    letter-spacing: 1px;
}

.copyright {
    font-size: 0.85rem;
    color: var(--text-muted);
}

.game-info {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.turn-indicator {
    background: var(--surface-color);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    padding: 0.75rem 1.5rem;
    border-radius: 999px;
    border: 1px solid var(--border-color);
    text-align: center;
    font-size: 1.25rem;
    font-weight: 600;
    align-self: center;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    transition: all 0.3s ease;
}

.turn-indicator.x-turn {
    box-shadow: 0 0 15px var(--x-glow);
    color: var(--x-color);
}

.turn-indicator.o-turn {
    box-shadow: 0 0 15px var(--o-glow);
    color: var(--o-color);
}

.scoreboard {
    display: flex;
    justify-content: space-between;
    gap: 1rem;
}

.score-card {
    flex: 1;
    background: var(--surface-color);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    padding: 1rem;
    border-radius: 16px;
    border: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.5rem;
    box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
}

.x-score { border-bottom: 3px solid var(--x-color); }
.o-score { border-bottom: 3px solid var(--o-color); }
.draws { border-bottom: 3px solid var(--text-muted); }

.score-card .label {
    font-size: 0.85rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    color: var(--text-muted);
}

.score-card .score {
    font-size: 2rem;
    font-weight: 800;
}

.board {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 0.75rem;
    aspect-ratio: 1;
    background: var(--surface-color);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    padding: 0.75rem;
    border-radius: 20px;
    border: 1px solid var(--border-color);
    box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
}

.cell {
    background: rgba(15, 23, 42, 0.6);
    border-radius: 12px;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 4rem;
    font-weight: 800;
    cursor: pointer;
    transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    box-shadow: inset 0 2px 4px rgba(0,0,0,0.2);
    user-select: none;
    position: relative;
    overflow: hidden;
}

.cell:hover:not(.occupied) {
    background: rgba(30, 41, 59, 0.8);
    transform: translateY(-2px);
}

.cell.x {
    color: var(--x-color);
    text-shadow: 0 0 15px var(--x-glow);
}

.cell.o {
    color: var(--o-color);
    text-shadow: 0 0 15px var(--o-glow);
}

/* Animations for X and O placement */
@keyframes popIn {
    0% { transform: scale(0.5); opacity: 0; }
    70% { transform: scale(1.1); }
    100% { transform: scale(1); opacity: 1; }
}

.cell .mark {
    animation: popIn 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275) forwards;
}

.cell.winning-cell {
    background: var(--win-bg);
    color: var(--win-color);
    text-shadow: 0 0 15px rgba(52, 211, 153, 0.6);
    border: 1px solid var(--win-color);
    animation: pulseWin 1.5s infinite;
}

@keyframes pulseWin {
    0% { box-shadow: 0 0 0 0 rgba(52, 211, 153, 0.4); }
    70% { box-shadow: 0 0 0 10px rgba(52, 211, 153, 0); }
    100% { box-shadow: 0 0 0 0 rgba(52, 211, 153, 0); }
}

.controls {
    display: flex;
    justify-content: center;
}

.btn {
    background: var(--surface-color);
    color: var(--text-main);
    border: 1px solid var(--border-color);
    padding: 0.85rem 2rem;
    font-family: inherit;
    font-size: 1rem;
    font-weight: 600;
    border-radius: 12px;
    cursor: pointer;
    transition: all 0.2s ease;
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
}

.btn:hover {
    background: rgba(255, 255, 255, 0.1);
    transform: translateY(-2px);
    box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
}

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

.primary-btn {
    background: linear-gradient(135deg, var(--x-color), var(--o-color));
    border: none;
    color: #fff;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
}

.primary-btn:hover {
    background: linear-gradient(135deg, #2ea8e5, #e060a3);
}

/* Modal */
.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(15, 23, 42, 0.8);
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
    display: flex;
    justify-content: center;
    align-items: center;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.3s ease;
    z-index: 100;
}

.modal-overlay.active {
    opacity: 1;
    pointer-events: all;
}

.modal-content {
    background: rgba(30, 41, 59, 0.9);
    padding: 2.5rem;
    border-radius: 24px;
    border: 1px solid var(--border-color);
    text-align: center;
    transform: scale(0.9) translateY(20px);
    transition: all 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
}

.modal-overlay.active .modal-content {
    transform: scale(1) translateY(0);
}

.modal-content h2 {
    font-size: 2.5rem;
    margin-bottom: 1.5rem;
    color: var(--text-main);
}

@media (max-width: 480px) {
    .cell {
        font-size: 3rem;
    }
    .score-card .score {
        font-size: 1.5rem;
    }
    h1 {
        font-size: 2rem;
    }
}