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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    color: #fff;
}

.container {
    width: 90%;
    max-width: 500px;
    padding: 20px;
}

.setup-screen, .practice-screen {
    background: rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(10px);
    border-radius: 20px;
    padding: 30px;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
}

.hidden {
    display: none !important;
}

h1 {
    text-align: center;
    margin-bottom: 30px;
    font-size: 28px;
    font-weight: 300;
}

.protocol-select {
    margin-bottom: 25px;
}

.protocol-option {
    background: rgba(255, 255, 255, 0.15);
    padding: 15px;
    border-radius: 12px;
    margin-bottom: 10px;
    cursor: pointer;
    transition: all 0.3s;
    border: 2px solid transparent;
}

.protocol-option:hover {
    background: rgba(255, 255, 255, 0.2);
}

.protocol-option.active {
    background: rgba(255, 255, 255, 0.25);
    border-color: rgba(255, 255, 255, 0.5);
}

.protocol-name {
    font-size: 18px;
    font-weight: 500;
    margin-bottom: 5px;
}

.protocol-desc {
    font-size: 14px;
    opacity: 0.8;
}

.rounds-control {
    margin-bottom: 25px;
    padding: 20px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 12px;
}

.rounds-label {
    display: block;
    margin-bottom: 15px;
    font-size: 16px;
}

.rounds-selector {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 20px;
}

.rounds-btn {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.2);
    border: none;
    color: #fff;
    font-size: 24px;
    cursor: pointer;
    transition: all 0.3s;
}

.rounds-btn:hover {
    background: rgba(255, 255, 255, 0.3);
    transform: scale(1.1);
}

.rounds-btn:disabled {
    opacity: 0.3;
    cursor: not-allowed;
    transform: scale(1);
}

.rounds-value {
    font-size: 32px;
    font-weight: 500;
    min-width: 60px;
    text-align: center;
}

.sound-settings {
    margin-bottom: 25px;
    padding: 20px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 12px;
}

.sound-title {
    font-size: 16px;
    margin-bottom: 15px;
}

.checkbox-group {
    margin-bottom: 15px;
}

.checkbox-label {
    display: flex;
    align-items: center;
    cursor: pointer;
    margin-bottom: 10px;
}

.checkbox-label input {
    margin-right: 10px;
    width: 20px;
    height: 20px;
    cursor: pointer;
}

.volume-control {
    display: flex;
    align-items: center;
    gap: 15px;
}

.volume-slider {
    flex: 1;
    height: 6px;
    border-radius: 3px;
    background: rgba(255, 255, 255, 0.2);
    outline: none;
    -webkit-appearance: none;
}

.volume-slider::-webkit-slider-thumb {
    -webkit-appearance: none;
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: #fff;
    cursor: pointer;
}

.start-btn {
    width: 100%;
    padding: 15px;
    font-size: 18px;
    font-weight: 500;
    color: #fff;
    background: rgba(255, 255, 255, 0.2);
    border: 2px solid rgba(255, 255, 255, 0.5);
    border-radius: 12px;
    cursor: pointer;
    transition: all 0.3s;
}

.start-btn:hover {
    background: rgba(255, 255, 255, 0.3);
    transform: translateY(-2px);
}

/* 练习界面 */
.practice-screen {
    text-align: center;
}

.progress-info {
    margin-bottom: 20px;
    font-size: 16px;
    opacity: 0.9;
}

.breath-circle-container {
    position: relative;
    width: 280px;
    height: 280px;
    margin: 40px auto;
    overflow: hidden;
}

.breath-circle {
    width: 200px;
    height: 200px;
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.2);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    transition: all 1s ease-in-out;
    box-shadow: 0 0 40px rgba(255, 255, 255, 0.3);
}

.breath-circle.inhale {
    width: 280px;
    height: 280px;
    background: rgba(100, 200, 255, 0.3);
    box-shadow: 0 0 60px rgba(100, 200, 255, 0.5);
}

.breath-circle.hold {
    width: 280px;
    height: 280px;
    background: rgba(200, 100, 255, 0.3);
    box-shadow: 0 0 60px rgba(200, 100, 255, 0.5);
}

.breath-circle.exhale {
    width: 200px;
    height: 200px;
    background: rgba(100, 255, 150, 0.3);
    box-shadow: 0 0 60px rgba(100, 255, 150, 0.5);
}

.phase-text {
    font-size: 36px;
    font-weight: 300;
    margin-bottom: 10px;
}

.countdown {
    font-size: 64px;
    font-weight: 500;
}

.step-info {
    margin-bottom: 30px;
    font-size: 18px;
}

.step-name {
    font-weight: 500;
    margin-bottom: 5px;
}

.cycle-info {
    opacity: 0.8;
    font-size: 16px;
}

.controls {
    display: flex;
    gap: 15px;
    justify-content: center;
}

.control-btn {
    padding: 12px 30px;
    font-size: 16px;
    color: #fff;
    background: rgba(255, 255, 255, 0.2);
    border: 2px solid rgba(255, 255, 255, 0.5);
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.3s;
}

.control-btn:hover {
    background: rgba(255, 255, 255, 0.3);
}

.completion-screen {
    text-align: center;
    padding: 40px 30px;
}

.completion-icon {
    font-size: 80px;
    margin-bottom: 20px;
}

.completion-text {
    font-size: 24px;
    margin-bottom: 30px;
}