body {
    background: #111;
    color: #eee;
}

.nettest-section {
    text-align: center;
    padding: 2em;
}

.algo-hint {
    font-size: 1.2em;
    margin-bottom: 2em;
}

.test-block {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 2em;
}

.chart-area {
    flex: 1 1 90%;
    max-width: 500px;
    min-width: 280px;
}

.chart-area canvas {
    background: #000;
    display: block;
    margin: 0 auto;
    width: 100%;           /* 自动适配 */
    height: auto;          /* 高度随宽度比例自适应 */
    border: 1px solid #444;
}

.speed-label, .result {
    margin-top: 0.5em;
    font-size: 1.1em;
}

.button-row {
    margin-top: 2em;
}

.button-row button {
    padding: 0.7em 2em;
    margin: 0 1em;
    font-size: 1em;
    background-color: #4a90e2;
    border: none;
    color: white;
    border-radius: 8px;
    cursor: pointer;
    transition: 0.3s;
}

.button-row button:hover {
    background-color: #3273c5;
}

@media (max-width: 600px) {
    .algo-hint {
        font-size: 1em;
        padding: 0 1em;
    }

    .speed-label, .result {
        font-size: 0.95em;
    }

    .button-row button {
        margin: 0.5em;
        font-size: 0.9em;
        padding: 0.5em 1.5em;
    }
}