/* 全局样式 */
body {
    font-family: 'Arial', sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    margin: 0;
    padding: 20px;
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
}

.container {
    text-align: center;
    width: 100%;
}

h1 {
    color: white;
    margin-bottom: 30px;
    text-shadow: 0 2px 4px rgba(0,0,0,0.3);
}

/* 卡片容器 */
.card-container {
    position: relative;
    width: 80%;
    max-width: 600px;
    margin: 0 auto 30px;
    height: 300px;
    perspective: 1000px;
}

/* 卡片样式 */
.card {
    position: absolute;
    width: 100%;
    height: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
    background: linear-gradient(45deg, #FF9A9E 0%, #FAD0C4 99%, #FAD0C4 100%);
    color: #333;
    font-size: 28px;
    font-weight: bold;
    border-radius: 20px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2);
    transition: all 0.5s ease;
    backface-visibility: hidden;
    opacity: 0;
    transform: translateZ(0) rotateY(0deg);
}

.card.active {
    opacity: 1;
    transform: translateZ(0) rotateY(0deg);
}

.card.inactive {
    opacity: 0;
    transform: translateZ(-100px) rotateY(-180deg);
}

/* 按钮容器 */
.button-container {
    display: flex;
    justify-content: center;
    gap: 20px;
}

/* 按钮样式 */
button {
    padding: 12px 24px;
    font-size: 16px;
    font-weight: bold;
    border: none;
    border-radius: 50px;
    cursor: pointer;
    background: linear-gradient(45deg, #4CAF50, #45a049);
    color: white;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
    transition: all 0.3s ease;
}

button:hover:not(:disabled) {
    transform: translateY(-3px);
    box-shadow: 0 6px 20px rgba(0, 0, 0, 0.3);
}

button:disabled {
    background: linear-gradient(45deg, #cccccc, #999999);
    cursor: not-allowed;
    transform: none;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
}

button:active:not(:disabled) {
    transform: translateY(1px);
}