/* 通用樣式 - 所有遊戲頁面共用 */

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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: #fff;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 20px;
    position: relative;
    overflow-x: hidden;
}

/* 星空背景動畫 */
body::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 0;
    background-image: 
        radial-gradient(2px 2px at 100px 200px, white, transparent),
        radial-gradient(2px 2px at 300px 150px, white, transparent),
        radial-gradient(2px 2px at 500px 300px, white, transparent),
        radial-gradient(2px 2px at 700px 100px, white, transparent),
        radial-gradient(2px 2px at 900px 250px, white, transparent),
        radial-gradient(2px 2px at 200px 400px, white, transparent),
        radial-gradient(2px 2px at 400px 450px, white, transparent),
        radial-gradient(2px 2px at 600px 500px, white, transparent),
        radial-gradient(2px 2px at 800px 350px, white, transparent),
        radial-gradient(2px 2px at 1000px 200px, white, transparent);
    animation: twinkle 3s infinite ease-in-out;
}

@keyframes twinkle {
    0%, 100% { opacity: 0.3; }
    50% { opacity: 1; }
}

/* 返回主頁按鈕 */
.home-button {
    position: fixed;
    top: 20px;
    left: 20px;
    z-index: 1000;
    background: rgba(255, 255, 255, 0.2);
    backdrop-filter: blur(10px);
    padding: 12px 20px;
    border-radius: 50px;
    text-decoration: none;
    color: #fff;
    font-weight: 600;
    display: flex;
    align-items: center;
    gap: 8px;
    transition: all 0.3s ease;
    border: 2px solid rgba(255, 255, 255, 0.3);
    box-shadow: 0 4px 15px rgba(0,0,0,0.2);
}

.home-button:hover {
    background: rgba(255, 255, 255, 0.3);
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(0,0,0,0.3);
}

.home-button:active {
    transform: translateY(0);
}

/* 遊戲容器 */
.game-container {
    position: relative;
    z-index: 1;
    background: rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(10px);
    border-radius: 20px;
    padding: 40px;
    box-shadow: 0 8px 32px rgba(0,0,0,0.3);
    border: 2px solid rgba(255, 255, 255, 0.2);
    max-width: 95vw;
    animation: fadeInUp 0.6s ease;
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* 遊戲標題 */
h1 {
    text-align: center;
    font-size: 2.5em;
    margin-bottom: 25px;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.3);
}

/* 畫布通用樣式 */
canvas {
    border: 3px solid rgba(255,255,255,0.3);
    border-radius: 10px;
    background: #1a1a2e;
    box-shadow: 0 4px 20px rgba(0,0,0,0.3);
    display: block;
    margin: 0 auto;
}

/* 按鈕通用樣式 */
button, .btn {
    padding: 15px 30px;
    font-size: 1.1em;
    font-weight: 600;
    border: none;
    border-radius: 50px;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 4px 15px rgba(0,0,0,0.2);
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    margin: 10px 5px;
}

button:hover, .btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(0,0,0,0.3);
}

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

button:disabled, .btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    transform: none;
}

/* 計分板 */
#scoreboard, .scoreboard {
    text-align: center;
    font-size: 1.5em;
    margin-bottom: 20px;
    font-weight: 600;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.3);
}

/* 響應式設計 */
@media (max-width: 768px) {
    body {
        padding: 10px;
    }

    .game-container {
        padding: 20px;
    }

    h1 {
        font-size: 1.8em;
    }

    canvas {
        max-width: 100%;
        height: auto;
    }

    button, .btn {
        padding: 12px 24px;
        font-size: 1em;
    }

    .home-button {
        top: 10px;
        left: 10px;
        padding: 10px 16px;
        font-size: 0.9em;
    }
}

@media (max-width: 480px) {
    .game-container {
        padding: 15px;
    }

    h1 {
        font-size: 1.5em;
    }

    #scoreboard, .scoreboard {
        font-size: 1.2em;
    }
}