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

:root {
    --primary: #FF6B6B;
    --secondary: #4ECDC4;
    --accent: #FFE66D;
    --success: #51CF66;
    --warning: #FFD43B;
    --danger: #FF6B6B;
    --bg: #F7F7F7;
    --text: #2C3E50;
    --text-light: #6C757D;
    --white: #FFFFFF;
    --shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 8px 30px rgba(0, 0, 0, 0.15);
    --radius: 16px;
    --radius-sm: 8px;
    --radius-lg: 24px;
}

body {
    font-family: 'PingFang SC', 'Microsoft YaHei', 'Nunito', sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    overflow: hidden;
}

#app {
    width: 100vw;
    height: 100vh;
    display: flex;
    flex-direction: column;
}

button {
    font-family: inherit;
    border: none;
    cursor: pointer;
    transition: all 0.2s ease;
}

button:active {
    transform: scale(0.95);
}

.sound-toggle {
    width: 48px;
    height: 48px;
    border-radius: 50%;
    background: var(--white);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 24px;
    box-shadow: var(--shadow);
}

.sound-toggle:hover {
    background: var(--accent);
}

.sound-icon {
    line-height: 1;
}