/* 基础样式 */
body {
    font-family: "微软雅黑", sans-serif;
    font-size: 16px;
    line-height: 1.6;
    margin: 0;
    padding: 20px;
    min-height: 100vh;
    transition: all 0.3s ease; /* 平滑过渡 */
}

.container {
    max-width: 800px;
    margin: 0 auto;
}

h1 {
    color: #333;
    text-align: center;
    margin-bottom: 20px;
    font-size: 2.2em;
    font-weight: bold;
}

.btn-group {
    text-align: center;
    margin: 20px 0;
}

.theme-btn {
    padding: 10px 20px;
    margin: 0 5px;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    font-size: 1em;
}

.content img {
    max-width: 100%;
    height: auto;
    border-radius: 8px;
    margin: 20px auto;
    display: block;
}


.footer {
    text-align: center;
    margin-top: 40px;
    padding: 15px;
    font-size: 0.9em;
    border-top: 3px solid #ddd;
}

/* 主题样式 */
.red-theme {
    background-color: #fff5f5;
    color: #c9302c;
}
.red-theme .theme-btn { background-color: #c9302c; color: white; }
.red-theme .footer { border-top-color: #c9302c; }

.green-theme {
    background-color: #f0f8eb;
    color: #2b572d;
}
.green-theme .theme-btn { background-color: #2b572d; color: white; }
.green-theme .footer { border-top-color: #2b572d; }

.blue-theme {
    background-color: #e0f3ff;
    color: #005f9e;
}
.blue-theme .theme-btn { background-color: #005f9e; color: white; }
.blue-theme .footer { border-top-color: #005f9e; }

.black-theme {
    background-color: #222;
    color: #fff;
}
.black-theme .theme-btn { background-color: #444; color: white; }
.black-theme .footer { border-top-color: #666; }
.size-btn {
    padding: 10px 18px;
    margin: 0 5px;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    font-size: 1em;
    background-color: #666;
    color: white;
    transition: background-color 0.3s;
}
 
 .red-theme .size-btn {
    background-color: #c9302c; /* 红色主题按钮颜色 */
}
.green-theme .size-btn {
    background-color: #2b572d; /* 绿色主题按钮颜色 */
}
.blue-theme .size-btn {
    background-color: #005f9e; /* 蓝色主题按钮颜色 */
}
.black-theme .size-btn {
    background-color: #444; /* 黑色主题按钮颜色 */
}

.size-btn:hover {
    opacity: 0.8; /* 鼠标悬停时透明度调整，增强交互感 */
}