* {
    box-sizing: border-box;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    margin: 0;
    padding: 20px;
    min-height: 100vh;
    background: linear-gradient(135deg, #1a1a2e 0%, #16213e 50%, #0f3460 100%);
    color: #e8e8e8;
    display: flex;
    justify-content: center;
    align-items: flex-start;
    transition: background 0.3s, color 0.3s;
}

.container {
    max-width: 550px;
    width: 100%;
    background: rgba(255, 255, 255, 0.08);
    backdrop-filter: blur(10px);
    padding: 30px;
    border-radius: 20px;
    box-shadow: 0 15px 35px rgba(0, 0, 0, 0.4);
    border: 1px solid rgba(255, 255, 255, 0.1);
}

h1 {
    margin: 0 0 5px 0;
    font-size: 2.5em;
    background: linear-gradient(135deg, #e74c3c, #9b59b6);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    text-align: center;
}

.subtitle {
    text-align: center;
    color: #aaa;
    margin: 0 0 25px 0;
    font-size: 0.95em;
}

.game-area {
    margin-bottom: 20px;
}

/* Players section */
.players {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 15px;
    margin-bottom: 20px;
}

.player {
    flex: 1;
    background: rgba(0, 0, 0, 0.3);
    border-radius: 12px;
    padding: 15px;
    text-align: center;
    border: 2px solid transparent;
    transition: all 0.3s;
}

.player-1 {
    border-color: rgba(231, 76, 60, 0.3);
}

.player-1.active {
    border-color: #e74c3c;
    background: rgba(231, 76, 60, 0.15);
    box-shadow: 0 0 20px rgba(231, 76, 60, 0.3);
}

.player-2 {
    border-color: rgba(52, 152, 219, 0.3);
}

.player-2.active {
    border-color: #3498db;
    background: rgba(52, 152, 219, 0.15);
    box-shadow: 0 0 20px rgba(52, 152, 219, 0.3);
}

.player-indicator {
    font-size: 0.7em;
    text-transform: uppercase;
    letter-spacing: 1px;
    color: #888;
    margin-bottom: 5px;
}

.player-name {
    font-size: 1.3em;
    font-weight: bold;
    margin-bottom: 5px;
}

.player-1 .player-name {
    color: #e74c3c;
}

.player-2 .player-name {
    color: #3498db;
}

.player-score {
    font-size: 0.9em;
    color: #aaa;
}

.player-score span {
    font-size: 1.5em;
    font-weight: bold;
    color: #f39c12;
}

.vs {
    font-size: 1.2em;
    font-weight: bold;
    color: #666;
    text-shadow: 0 0 10px rgba(255, 255, 255, 0.1);
}

/* Turn indicator */
.turn-indicator {
    text-align: center;
    padding: 12px;
    background: linear-gradient(135deg, rgba(155, 89, 182, 0.3), rgba(142, 68, 173, 0.3));
    border-radius: 10px;
    margin-bottom: 20px;
    font-weight: bold;
    font-size: 1.1em;
}

/* Word display */
.word-display {
    display: flex;
    justify-content: center;
    gap: 8px;
    margin: 25px 0;
    flex-wrap: wrap;
    min-height: 60px;
    align-items: center;
}

.word-display .placeholder-text {
    color: #666;
    font-style: italic;
}

.word-display .letter {
    width: 50px;
    height: 60px;
    background: linear-gradient(135deg, rgba(155, 89, 182, 0.4), rgba(142, 68, 173, 0.4));
    border: 2px solid rgba(155, 89, 182, 0.5);
    border-radius: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.8em;
    font-weight: bold;
    color: #fff;
    animation: letterPop 0.3s ease forwards;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.3);
}

@keyframes letterPop {
    0% {
        transform: scale(0);
        opacity: 0;
    }
    60% {
        transform: scale(1.2);
    }
    100% {
        transform: scale(1);
        opacity: 1;
    }
}

.word-display.word-complete .letter {
    background: linear-gradient(135deg, rgba(231, 76, 60, 0.6), rgba(192, 57, 43, 0.6));
    border-color: #e74c3c;
    animation: wordComplete 0.5s ease;
}

@keyframes wordComplete {
    0%, 100% { transform: scale(1); }
    25% { transform: scale(1.1) rotate(-5deg); }
    75% { transform: scale(1.1) rotate(5deg); }
}

/* Input area */
.input-area {
    display: flex;
    gap: 10px;
    margin-bottom: 15px;
}

#letter-input {
    flex: 1;
    padding: 15px;
    font-size: 1.5em;
    text-align: center;
    text-transform: uppercase;
    border: 2px solid rgba(255, 255, 255, 0.2);
    border-radius: 10px;
    background: rgba(0, 0, 0, 0.3);
    color: #fff;
    outline: none;
    transition: border-color 0.3s;
}

#letter-input:focus {
    border-color: #9b59b6;
}

#letter-input::placeholder {
    color: #666;
    text-transform: none;
    font-size: 0.7em;
}

#submit-btn {
    padding: 15px 30px;
    font-size: 1.1em;
    background: linear-gradient(135deg, #27ae60, #2ecc71);
    color: white;
    border: none;
    border-radius: 10px;
    cursor: pointer;
    transition: all 0.3s;
    font-weight: bold;
}

#submit-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 20px rgba(39, 174, 96, 0.4);
}

#submit-btn:active {
    transform: translateY(0);
}

#submit-btn:disabled {
    background: #555;
    cursor: not-allowed;
    transform: none;
}

/* Game controls */
.game-controls {
    display: flex;
    gap: 10px;
    margin-bottom: 20px;
    justify-content: center;
}

.challenge-btn {
    padding: 12px 25px;
    font-size: 1em;
    background: linear-gradient(135deg, #e74c3c, #c0392b);
    color: white;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.3s;
    font-weight: bold;
}

.challenge-btn:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(231, 76, 60, 0.4);
}

.challenge-btn:disabled {
    background: #555;
    cursor: not-allowed;
    transform: none;
}

.new-round-btn {
    padding: 12px 25px;
    font-size: 1em;
    background: linear-gradient(135deg, #3498db, #2980b9);
    color: white;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.3s;
    font-weight: bold;
}

.new-round-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(52, 152, 219, 0.4);
}

/* Round info */
.round-info {
    display: flex;
    justify-content: center;
    gap: 30px;
    color: #888;
    font-size: 0.9em;
    margin-bottom: 15px;
}

.round-info strong {
    color: #f39c12;
}

/* Message */
.message {
    text-align: center;
    font-size: 1.1em;
    font-weight: bold;
    min-height: 30px;
    margin: 15px 0;
    transition: color 0.3s;
    padding: 10px;
    border-radius: 8px;
}

.message.success {
    color: #2ecc71;
    background: rgba(46, 204, 113, 0.1);
}

.message.error {
    color: #e74c3c;
    background: rgba(231, 76, 60, 0.1);
}

.message.info {
    color: #3498db;
    background: rgba(52, 152, 219, 0.1);
}

/* Settings */
.settings {
    display: flex;
    gap: 10px;
    align-items: center;
    justify-content: center;
    margin-bottom: 20px;
    flex-wrap: wrap;
}

.settings label {
    color: #aaa;
    font-size: 0.85em;
}

#game-mode, #ai-difficulty {
    padding: 8px 12px;
    font-size: 0.85em;
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 6px;
    background: rgba(0, 0, 0, 0.3);
    color: #fff;
    cursor: pointer;
}

#new-game-btn {
    padding: 8px 15px;
    font-size: 0.85em;
    background: linear-gradient(135deg, #9b59b6, #8e44ad);
    color: white;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    transition: all 0.3s;
}

#new-game-btn:hover {
    transform: translateY(-1px);
    box-shadow: 0 3px 10px rgba(155, 89, 182, 0.4);
}

#theme-toggle {
    padding: 8px 15px;
    font-size: 0.85em;
    background: rgba(255, 255, 255, 0.1);
    color: #aaa;
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 6px;
    cursor: pointer;
    transition: all 0.3s;
}

#theme-toggle:hover {
    background: rgba(255, 255, 255, 0.2);
    color: #fff;
}

/* Instructions */
.instructions {
    background: rgba(0, 0, 0, 0.2);
    border-radius: 12px;
    padding: 15px 20px;
    font-size: 0.85em;
}

.instructions h3 {
    margin: 0 0 10px 0;
    color: #9b59b6;
    font-size: 1em;
}

.instructions ul {
    margin: 0;
    padding-left: 20px;
    color: #aaa;
}

.instructions li {
    margin-bottom: 5px;
}

.instructions strong {
    color: #e74c3c;
}

/* Music controls */
.music-controls {
    position: fixed;
    bottom: 20px;
    right: 20px;
    background: rgba(0, 0, 0, 0.8);
    padding: 12px 15px;
    border-radius: 12px;
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.3);
    font-size: 0.85em;
    z-index: 1000;
    border: 1px solid rgba(255, 255, 255, 0.1);
}

.music-controls button {
    padding: 8px 12px;
    font-size: 0.9em;
    margin: 3px;
    background: rgba(255, 255, 255, 0.1);
    color: #aaa;
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 6px;
    cursor: pointer;
    transition: all 0.3s;
}

.music-controls button:hover {
    background: rgba(255, 255, 255, 0.2);
    color: #fff;
}

.music-controls .song-name {
    font-size: 0.8em;
    color: #666;
    margin-top: 8px;
    text-align: center;
}

/* Light theme */
body.light {
    background: linear-gradient(135deg, #f5f7fa 0%, #e4e8ec 100%);
    color: #333;
}

body.light .container {
    background: rgba(255, 255, 255, 0.95);
    border-color: rgba(0, 0, 0, 0.1);
    box-shadow: 0 15px 35px rgba(0, 0, 0, 0.1);
}

body.light h1 {
    background: linear-gradient(135deg, #c0392b, #8e44ad);
    -webkit-background-clip: text;
    background-clip: text;
}

body.light .subtitle {
    color: #666;
}

body.light .player {
    background: rgba(0, 0, 0, 0.05);
}

body.light .player-indicator {
    color: #666;
}

body.light .player-score {
    color: #666;
}

body.light .turn-indicator {
    background: linear-gradient(135deg, rgba(155, 89, 182, 0.2), rgba(142, 68, 173, 0.2));
    color: #333;
}

body.light .word-display .placeholder-text {
    color: #999;
}

body.light .word-display .letter {
    background: linear-gradient(135deg, rgba(155, 89, 182, 0.3), rgba(142, 68, 173, 0.3));
    border-color: rgba(155, 89, 182, 0.4);
    color: #333;
}

body.light #letter-input {
    background: rgba(0, 0, 0, 0.05);
    border-color: rgba(0, 0, 0, 0.15);
    color: #333;
}

body.light #letter-input::placeholder {
    color: #999;
}

body.light .round-info {
    color: #666;
}

body.light #game-mode,
body.light #ai-difficulty {
    background: rgba(0, 0, 0, 0.05);
    border-color: rgba(0, 0, 0, 0.15);
    color: #333;
}

body.light #theme-toggle {
    background: rgba(0, 0, 0, 0.05);
    border-color: rgba(0, 0, 0, 0.15);
    color: #666;
}

body.light .instructions {
    background: rgba(0, 0, 0, 0.05);
}

body.light .instructions ul {
    color: #666;
}

body.light .music-controls {
    background: rgba(255, 255, 255, 0.95);
    border-color: rgba(0, 0, 0, 0.1);
}

body.light .music-controls button {
    background: rgba(0, 0, 0, 0.05);
    border-color: rgba(0, 0, 0, 0.15);
    color: #666;
}

body.light .music-controls button:hover {
    background: rgba(0, 0, 0, 0.1);
    color: #333;
}

/* Mobile responsive */
@media (max-width: 520px) {
    body {
        padding: 10px;
    }

    .container {
        padding: 20px 15px;
    }

    h1 {
        font-size: 2em;
    }

    .players {
        flex-direction: column;
        gap: 10px;
    }

    .player {
        width: 100%;
    }

    .vs {
        display: none;
    }

    .word-display .letter {
        width: 40px;
        height: 50px;
        font-size: 1.5em;
    }

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

    #submit-btn {
        width: 100%;
    }

    .game-controls {
        flex-direction: column;
    }

    .challenge-btn,
    .new-round-btn {
        width: 100%;
    }

    .settings {
        flex-direction: column;
        gap: 8px;
    }

    .settings > * {
        width: 100%;
    }

    #game-mode,
    #ai-difficulty,
    #new-game-btn,
    #theme-toggle {
        width: 100%;
        text-align: center;
    }

    .music-controls {
        bottom: 10px;
        right: 10px;
        left: 10px;
        text-align: center;
    }
}