:root {
    --bg-color: #0f172a;
    --key-bg: #1e293b;
    --key-text: #94a3b8;
    --primary-color: #38bdf8;
    --secondary-color: #818cf8;
}

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background-color: var(--bg-color);
    background-image: 
        radial-gradient(circle at 20% 30%, rgba(56, 189, 248, 0.05) 0%, transparent 40%),
        radial-gradient(circle at 80% 70%, rgba(129, 140, 248, 0.05) 0%, transparent 40%);
    color: white;
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: flex-start; /* 改为从顶部开始，方便滚动 */
    overflow-y: auto; /* 允许纵向滚动 */
    overflow-x: hidden;
    padding: 40px 20px; /* 增加上下边距 */
}

.container {
    text-align: center;
    width: 100%;
    max-width: 1100px;
    margin: 0 auto;
}

header h1 {
    font-size: 3rem; /* 稍微缩小标题，原为 3.5rem */
    margin-bottom: 0.5rem;
    background: linear-gradient(to right, #38bdf8, #818cf8, #c084fc);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    letter-spacing: -2px;
    font-weight: 800;
    animation: titleGlow 3s ease-in-out infinite alternate;
    line-height: 1.2; /* 增加行高防止裁剪 */
}

@keyframes titleGlow {
    from {
        filter: drop-shadow(0 0 5px rgba(56, 189, 248, 0.2));
    }
    to {
        filter: drop-shadow(0 0 20px rgba(129, 140, 248, 0.6));
    }
}

header p {
    color: var(--key-text);
    margin-bottom: 3rem;
    font-size: 1.1rem;
    opacity: 0.8;
}

.keyboard {
    display: flex;
    flex-direction: column;
    gap: 12px;
    padding: 35px;
    background: rgba(30, 41, 59, 0.4);
    border-radius: 24px;
    box-shadow: 0 20px 50px rgba(0, 0, 0, 0.5);
    backdrop-filter: blur(12px);
    border: 1px solid rgba(255, 255, 255, 0.08);
}

.keyboard-row {
    display: flex;
    gap: 12px;
    justify-content: center;
}

/* 错位排列 */
.row-1 { transform: translateX(10px); }
.row-2 { transform: translateX(25px); }
.row-3 { transform: translateX(45px); }

.key {
    background-color: var(--key-bg);
    border: 1px solid rgba(255, 255, 255, 0.05);
    border-radius: 12px;
    width: 65px;
    height: 65px;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    cursor: pointer;
    transition: all 0.15s cubic-bezier(0.4, 0, 0.2, 1);
    user-select: none;
    position: relative;
    overflow: hidden;
}

.key .char {
    font-size: 1.4rem;
    font-weight: 700;
    color: var(--key-text);
    z-index: 2;
}

.key .note {
    font-size: 0.75rem;
    color: rgba(148, 163, 184, 0.4);
    margin-top: 2px;
    z-index: 2;
    text-transform: uppercase;
}

.key.active {
    background-color: var(--row-color);
    transform: scale(0.92) translateY(3px);
    box-shadow: 0 0 40px var(--row-color);
    border-color: rgba(255, 255, 255, 0.4);
}

.key.active .char {
    color: white;
}

.key.active .note {
    color: rgba(255, 255, 255, 0.7);
}

/* 涟漪效果 */
.ripple {
    position: absolute;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.5);
    transform: scale(0);
    animation: ripple-animation 0.5s ease-out;
    pointer-events: none;
    z-index: 1;
}

@keyframes ripple-animation {
    to {
        transform: scale(4);
        opacity: 0;
    }
}

/* 波纹效果 */
.wave {
    position: absolute;
    border: 2px solid var(--row-color);
    border-radius: 50%;
    pointer-events: none;
    z-index: -1;
    animation: wave-animation 1.2s cubic-bezier(0, 0.2, 0.8, 1) forwards;
}

@keyframes wave-animation {
    0% {
        width: 0;
        height: 0;
        opacity: 0.8;
        transform: translate(-50%, -50%);
    }
    100% {
        width: 600px;
        height: 600px;
        opacity: 0;
        transform: translate(-50%, -50%);
    }
}

.instructions {
    margin-top: 3rem;
    color: var(--key-text);
    font-size: 1rem;
    letter-spacing: 1px;
    text-transform: uppercase;
    font-weight: 500;
    opacity: 0.6;
}

.song-box {
    margin-top: 2rem;
    padding: 20px;
    background: rgba(255, 255, 255, 0.03);
    border-radius: 16px;
    border: 1px solid rgba(255, 255, 255, 0.05);
}

.song-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
    gap: 15px;
    flex-wrap: wrap;
}

.song-selector-group {
    display: flex;
    align-items: center;
    gap: 12px;
}

.song-select {
    background: rgba(30, 41, 59, 0.8);
    color: white;
    border: 1px solid rgba(255, 255, 255, 0.2);
    padding: 8px 12px;
    border-radius: 12px;
    font-size: 0.95rem;
    cursor: pointer;
    outline: none;
    transition: all 0.3s ease;
}

.song-select:focus {
    border-color: var(--primary-color);
    box-shadow: 0 0 10px rgba(56, 189, 248, 0.2);
}

.btn-autoplay {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    border: none;
    padding: 8px 20px;
    border-radius: 12px;
    cursor: pointer;
    font-weight: bold;
    font-size: 0.9rem;
    transition: all 0.3s ease;
    box-shadow: 0 4px 15px rgba(56, 189, 248, 0.3);
}

.btn-upload {
    background: rgba(255, 255, 255, 0.1);
    color: white;
    border: 1px solid rgba(255, 255, 255, 0.1);
    padding: 8px 16px;
    border-radius: 12px;
    cursor: pointer;
    font-size: 0.9rem;
    transition: all 0.3s ease;
}

.btn-upload:hover {
    background: rgba(255, 255, 255, 0.2);
}

.btn-autoplay:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(56, 189, 248, 0.5);
    filter: brightness(1.1);
}

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

.btn-autoplay.playing {
    background: #ef4444;
    box-shadow: 0 4px 15px rgba(239, 68, 68, 0.3);
}

.score {
    display: flex;
    flex-direction: column;
    gap: 8px;
    font-family: 'Courier New', Courier, monospace;
}

.segment {
    font-size: 1.2rem;
    letter-spacing: 4px;
    color: var(--secondary-color);
}

.keys {
    font-size: 1.5rem;
    font-weight: bold;
    letter-spacing: 6px;
    color: white;
    background: rgba(56, 189, 248, 0.1);
    padding: 5px;
    border-radius: 8px;
}

.lyrics {
    font-size: 0.9rem;
    color: var(--key-text);
    margin-top: 5px;
    letter-spacing: 2px;
}