/* Reset and base styles */
* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #2c3e50, #34495e);
    color: #ecf0f1;
    padding: 20px;
    min-height: 100vh;
}

.container {
    max-width: 550px;
    margin: 0 auto;
    background: rgba(255, 255, 255, 0.05);
    border-radius: 15px;
    padding: 30px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.3);
}

/* Header section */
header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 25px;
}

h1 {
    font-size: 80px;
    font-weight: 900;
    color: #ecf0f1;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.5);
}

.scores {
    display: flex;
    gap: 15px;
}

.score-box {
    background: rgba(255, 255, 255, 0.1);
    padding: 12px 18px;
    border-radius: 10px;
    text-align: center;
    min-width: 90px;
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.2);
}

.score-label {
    color: #bdc3c7;
    font-size: 11px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 1px;
}

#score, #best {
    color: #ecf0f1;
    font-size: 22px;
    font-weight: 700;
}

/* Player section */
.player-section {
    margin-bottom: 25px;
    background: rgba(255, 255, 255, 0.05);
    padding: 20px;
    border-radius: 10px;
    border: 1px solid rgba(255, 255, 255, 0.1);
}

.player-section h2 {
    font-size: 18px;
    margin-bottom: 15px;
    color: #ecf0f1;
}

.player-input {
    display: flex;
    gap: 10px;
    margin-bottom: 15px;
}

#player-name {
    flex: 1;
    padding: 10px;
    border: none;
    border-radius: 5px;
    background: rgba(255, 255, 255, 0.9);
    color: #2c3e50;
    font-size: 14px;
}

#add-player {
    padding: 10px 15px;
    background: #3498db;
    color: white;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    font-weight: 600;
    transition: background 0.3s;
}

#add-player:hover {
    background: #2980b9;
}

#download-names {
    padding: 8px 12px;
    background: #e74c3c;
    color: white;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    font-size: 12px;
    transition: background 0.3s;
}

#download-names:hover {
    background: #c0392b;
}

#player-list {
    max-height: 150px;
    overflow-y: auto;
    background: rgba(0, 0, 0, 0.2);
    border-radius: 5px;
    padding: 10px;
}

#player-list ul {
    list-style: none;
}

#player-list li {
    padding: 5px 0;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
    color: #ecf0f1;
}

/* Game intro */
.game-intro {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 25px;
}

.game-intro p {
    font-size: 16px;
    color: #bdc3c7;
}

#new-game {
    background: linear-gradient(45deg, #f39c12, #e67e22);
    color: white;
    border: none;
    padding: 12px 24px;
    border-radius: 25px;
    font-weight: 700;
    cursor: pointer;
    font-size: 16px;
    transition: all 0.3s;
    box-shadow: 0 4px 15px rgba(243, 156, 18, 0.3);
}

#new-game:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(243, 156, 18, 0.4);
}

/* Game container */
.game-container {
    background: rgba(0, 0, 0, 0.3);
    padding: 20px;
    border-radius: 15px;
    margin-bottom: 25px;
    position: relative;
    border: 2px solid rgba(255, 255, 255, 0.1);
}

#game-board {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    grid-template-rows: repeat(4, 1fr);
    gap: 12px;
    width: 100%;
    aspect-ratio: 1;
}

.grid-cell {
    background: rgba(255, 255, 255, 0.1);
    border-radius: 8px;
    border: 1px solid rgba(255, 255, 255, 0.05);
}

.tile {
    position: absolute;
    display: flex;
    justify-content: center;
    align-items: center;
    font-weight: 700;
    font-size: 32px;
    border-radius: 8px;
    transition: all 0.15s ease-in-out;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
    animation: tileAppear 0.2s ease-out;
}

@keyframes tileAppear {
    from {
        transform: scale(0);
        opacity: 0;
    }
    to {
        transform: scale(1);
        opacity: 1;
    }
}

.tile-2 {
    background: linear-gradient(135deg, #eee4da, #ede0c8);
    color: #776e65;
}

.tile-4 {
    background: linear-gradient(135deg, #ede0c8, #f2b179);
    color: #776e65;
}

.tile-8 {
    background: linear-gradient(135deg, #f2b179, #f59563);
    color: white;
}

.tile-16 {
    background: linear-gradient(135deg, #f59563, #f67c5f);
    color: white;
}

.tile-32 {
    background: linear-gradient(135deg, #f67c5f, #f65e3b);
    color: white;
}

.tile-64 {
    background: linear-gradient(135deg, #f65e3b, #edcf72);
    color: white;
}

.tile-128 {
    background: linear-gradient(135deg, #edcf72, #edcc61);
    color: white;
    font-size: 28px;
}

.tile-256 {
    background: linear-gradient(135deg, #edcc61, #edc850);
    color: white;
    font-size: 28px;
}

.tile-512 {
    background: linear-gradient(135deg, #edc850, #edc53f);
    color: white;
    font-size: 28px;
}

.tile-1024 {
    background: linear-gradient(135deg, #edc53f, #edc22e);
    color: white;
    font-size: 24px;
}

.tile-2048 {
    background: linear-gradient(135deg, #edc22e, #3e5871);
    color: white;
    font-size: 24px;
    box-shadow: 0 4px 20px rgba(237, 194, 46, 0.5);
}

/* Game message overlay */
.game-message {
    display: none;
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(44, 62, 80, 0.9);
    flex-direction: column;
    align-items: center;
    justify-content: center;
    border-radius: 15px;
    z-index: 100;
    backdrop-filter: blur(5px);
}

.game-message p {
    font-size: 48px;
    font-weight: 900;
    color: #ecf0f1;
    margin-bottom: 25px;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.5);
}

#try-again {
    background: linear-gradient(45deg, #e74c3c, #c0392b);
    color: white;
    border: none;
    padding: 15px 30px;
    border-radius: 25px;
    font-weight: 700;
    cursor: pointer;
    font-size: 18px;
    transition: all 0.3s;
    box-shadow: 0 4px 15px rgba(231, 76, 60, 0.3);
}

#try-again:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(231, 76, 60, 0.4);
}

/* Instructions */
.instructions {
    text-align: center;
    font-size: 14px;
    color: #bdc3c7;
    margin-top: 20px;
}

.instructions strong {
    color: #ecf0f1;
}

/* Mobile responsiveness */
@media (max-width: 600px) {
    body {
        padding: 10px;
    }

    .container {
        padding: 20px;
    }

    h1 {
        font-size: 60px;
    }

    .score-box {
        min-width: 75px;
        padding: 10px 15px;
    }

    #score, #best {
        font-size: 20px;
    }

    .tile {
        font-size: 24px;
    }

    .tile-128, .tile-256, .tile-512 {
        font-size: 20px;
    }

    .tile-1024, .tile-2048 {
        font-size: 16px;
    }

    .player-input {
        flex-direction: column;
    }

    #add-player, #download-names {
        width: 100%;
    }
}