/* 基础样式 */
body {
    font-family: 'Roboto', 'HarmonyOS Sans SC', sans-serif;
    margin: 0;
    padding: 20px;
    background: #121212;
    color: #e3f2fd;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
}

.container {
    text-align: center;
    background: #1e1e1e;
    padding: 48px;
    border-radius: 24px;
    box-shadow: 0 4px 16px rgba(0,0,0,0.32);
    animation: fadeIn 0.3s ease-in-out;
}

.time {
    font-size: 160px;
    margin: 0;
    color: #90caf9;
    font-weight: 400;
    text-shadow: 0 2px 8px rgba(25, 118, 210, 0.10);
}

.text {
    font-size: 1.8rem;
    margin-bottom: 32px;
    color: #e3f2fd;
}

.controls {
    margin-top: 40px;
    display: flex;
    gap: 12px;
    flex-wrap: wrap;
    justify-content: center;
}

.btn,
#fontSelector {
    padding: 12px 24px;
    border: none;
    border-radius: 20px;
    cursor: pointer;
    transition: all 0.2s cubic-bezier(.4,0,.2,1);
    font-size: 1rem;
    font-weight: 500;
    background-color: #232a34;
    color: #e3f2fd;
    box-shadow: 0 1px 3px rgba(0,0,0,0.32);
}

.btn:hover,
#fontSelector:hover {
    background-color: #1976d2;
    color: #fff;
    transform: translateY(-1px) scale(1.03);
    box-shadow: 0 2px 6px rgba(25, 118, 210, 0.18);
}

#fontSelector {
    padding: 10px 20px;
}

.btn.fullscreen {
    background-color: #1976d2;
    color: #fff;
}

.btn.fullscreen:hover {
    background-color: #1565c0;
}

/* 返回按钮样式 */
#return-btn {
    position: absolute; /* 绝对定位 */
    top: 20px; /* 距离顶部 20px */
    left: 20px; /* 距离左侧 20px */
    padding: 12px 24px; /* 内边距 */
    font-size: 1rem; /* 字体大小 */
    cursor: pointer; /* 鼠标悬停时显示为手型 */
    background-color: #232a34; /* 按钮背景颜色 */
    color: #e3f2fd; /* 按钮文字颜色 */
    border: 1px solid #1976d2; /* 按钮边框样式 */
    border-radius: 20px; /* 按钮圆角大小 */
    box-shadow: 0 1px 3px rgba(0,0,0,0.32); /* 按钮阴影 */
    transition: all 0.2s cubic-bezier(.4,0,.2,1); /* 背景颜色和缩放的过渡效果 */
    z-index: 1001; /* 按钮层级 */
}

#return-btn:hover {
    background-color: #1976d2; /* 悬停时的背景颜色 */
    color: #fff;
    transform: translateY(-1px) scale(1.03); /* 悬停时向上移动 1px */
    box-shadow: 0 2px 6px rgba(25, 118, 210, 0.18); /* 悬停时的阴影效果 */
}

/* 简化动画效果 */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.font-size-control {
    display: flex;
    align-items: center;
    gap: 4px;
}

#fontSizeInput {
    width: 70px;
    text-align: center;
    padding: 12px 8px;
    background: #181c1f;
    color: #90caf9;
    border: 1px solid #232a34;
    border-radius: 12px;
}

.unit {
    color: #90caf9;
    font-size: 0.9rem;
}