/* 背景渐变 */
body {
    margin: 0;
    font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, rgb(214, 238, 250), rgb(180, 222, 250), rgb(240, 248, 255));
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
}

/* 白色容器 */
.container {
    background-color: #ffffff;
    padding: 30px 40px;
    border-radius: 20px;
    box-shadow: 0 8px 20px rgba(0,0,0,0.1);
    width: 350px;
    text-align: center;
}

/* 标题 */
.container h1 {
    margin-bottom: 20px;
    font-size: 24px;
    color: #333;
}

/* 表单组居中排列 */
.form-group {
    display: flex;
    flex-direction: column;
    align-items: center;
    margin-bottom: 15px;
}

/* 下拉框和输入框统一样式 */
select, input[type="number"] {
    width: 60%;               /* 输入框和选择框不要太长 */
    padding: 8px 12px;
    border-radius: 10px;      /* 圆角 */
    border: 1px solid #ccc;
    font-size: 16px;
    margin-top: 5px;          /* 标签与控件间距 */
    text-align: center;       /* 输入文字居中 */
    background-color: rgb(240, 248, 255); /* 浅蓝背景 */
    color: #333;
    outline: none;
}

/* 优化选择框弹出菜单样式 */
select {
    appearance: none;          /* 移除默认样式 */
    -webkit-appearance: none;
    -moz-appearance: none;
    background-image: url("data:image/svg+xml;charset=US-ASCII,%3Csvg width='12' height='12' viewBox='0 0 24 24' fill='none' stroke='%23333' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpolyline points='6 9 12 15 18 9'%3E%3C/polyline%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 10px center;
    background-size: 12px;
    cursor: pointer;
}

/* 鼠标悬停改变边框颜色 */
select:hover, input[type="number"]:hover {
    border-color: rgb(100, 180, 250);
}

/* 按钮居中 */
button {
    display: block;
    margin: 0 auto 20px auto;
    background-color: rgb(100, 180, 250);
    color: #fff;
    border: none;
    padding: 10px 20px;
    border-radius: 15px;
    font-size: 16px;
    cursor: pointer;
    transition: background-color 0.3s;
}

button:hover {
    background-color: rgb(70, 150, 220);
}

/* 进度环 */
.progress-ring {
    position: relative;
    width: 150px;
    height: 150px;
    margin: 20px auto;
}

.progress-ring svg {
    transform: rotate(-90deg);
    width: 150px;
    height: 150px;
}

.progress-ring circle {
    fill: transparent;
    stroke-width: 12;
    stroke-linecap: round;
    stroke: rgb(100, 180, 250);
}

.progress-ring circle.bg {
    stroke: #eee;
}

.progress-ring circle.progress {
    stroke-dasharray: 339.292; /* 2*PI*54 */
    stroke-dashoffset: 339.292;
    transition: stroke-dashoffset 0.2s linear;
}

/* 中心文字 */
.progress-text {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    font-size: 18px;
    font-weight: bold;
    color: #333;
}

/* 测速结果 */
.results {
    margin-top: 15px;
    font-size: 16px;
    color: #333;
}

.results p {
    margin: 5px 0;
}