body {
    font-family: Arial, sans-serif;
    background: linear-gradient(135deg, #667eea, #764ba2);
    color: #fff;
    margin: 0;
    padding: 0;
    text-align: center;
}

header {
    padding: 15px;
}

button.tab-btn {
    padding: 10px 20px;
    margin: 5px;
    font-size: 1em;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    background: #4caf50;
    color: #fff;
    transition: 0.3s;
}

button.tab-btn:hover {
    background: #45a049;
}

.game-container {
    display: none;
    justify-content: center;
    align-items: center;
    min-height: 80vh;
}

.game-container.active {
    display: flex;
}

.container, .quiz-container, .guess-game {
    background: rgba(255,255,255,0.15);
    padding: 30px;
    border-radius: 15px;
    width: 400px;
    box-shadow: 0 10px 25px rgba(0,0,0,0.3);
    margin: auto;
}

.board {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 10px;
    margin: 20px 0;
}

.cell {
    width: 100px;
    height: 100px;
    background: rgba(255,255,255,0.2);
    border: 2px solid #fff;
    border-radius: 10px;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 2.5em;
    font-weight: bold;
    cursor: pointer;
    transition: background 0.3s, transform 0.2s;
}

.cell:hover { background: rgba(255,255,255,0.3); transform: scale(1.05);}
.cell.taken { cursor: not-allowed;}

.quiz-container .question { font-size: 1.2em; margin-bottom: 20px; }
.quiz-container .options { display: flex; flex-direction: column; gap: 10px; }
.quiz-container .option {
    padding: 10px;
    background: rgba(255,255,255,0.25);
    border: none;
    border-radius: 8px;
    cursor: pointer;
    color: #fff;
    transition: 0.3s;
}
.quiz-container .option:hover { background: rgba(255,255,255,0.45); }
.quiz-container .option.correct { background: #4caf50; color: #fff; }
.quiz-container .option.wrong { background: #f44336; color: #fff; }
.quiz-container .message { margin-top: 15px; font-size: 1.1em; }
#nextBtn {
    margin-top: 15px;
    padding: 10px 20px;
    font-size: 1em;
    border: none;
    border-radius: 5px;
    background: #3498db;
    color: white;
    cursor: pointer;
    transition: 0.3s;
}
#nextBtn:hover { background: #2980b9; }

.guess-game input {
    padding: 10px;
    font-size: 1em;
    width: 80%;
    border-radius: 5px;
    border: none;
    outline: none;
    text-align: center;
}

.guess-game button {
    margin-top: 15px;
    padding: 10px 20px;
    font-size: 1em;
    border: none;
    border-radius: 5px;
    background: #4caf50;
    color: white;
    cursor: pointer;
    transition: 0.3s;
}

.guess-game button:hover { background: #45a049; }
.guess-game .message { margin-top: 15px; font-size: 1.1em; }
.guess-game .success { color: #ffeb3b; font-weight: bold; }

.signature { margin-top: 20px; font-size: 0.85em; opacity: 0.8;}
.signature span { color: #ffeb3b; font-weight: bold; }

button {
    padding: 10px 20px;
    background: #4caf50;
    color: white;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    font-size: 1em;
    margin-top: 20px;
    transition: background 0.3s;
}
button:hover { background: #45a049; }