body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    margin: 0;
    padding: 20px;
    background-color: #f5f5f5;
    color: #333;
}

.container {
    max-width: 900px;
    margin: 0 auto;
    background-color: white;
    padding: 30px;
    border-radius: 10px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

h1 {
    text-align: center;
    color: #2c3e50;
    margin-bottom: 30px;
}

.controls {
    background-color: #f8f9fa;
    padding: 20px;
    border-radius: 8px;
    margin-bottom: 20px;
    border: 1px solid #e9ecef;
}

#functions-list {
    margin-bottom: 15px;
}

.function-row {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 10px;
}

.function-row label {
    font-weight: 600;
    min-width: 40px; /* 缩短label宽度 */
}

.function-row input[type="text"] {
    flex-grow: 1;
    padding: 10px;
    border: 1px solid #ced4da;
    border-radius: 4px;
    font-size: 16px;
}

.function-row input[type="color"] {
    width: 40px;
    height: 40px;
    border: none;
    padding: 0;
    background: none;
    cursor: pointer;
}

.remove-btn {
    background-color: #e74c3c;
    color: white;
    border: none;
    width: 30px;
    height: 30px;
    border-radius: 4px; /* 改为方形圆角 */
    cursor: pointer;
    font-weight: bold;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: background-color 0.2s;
    flex-shrink: 0; /* 防止被压缩 */
}

.remove-btn:hover {
    background-color: #c0392b;
}

.secondary-btn {
    background-color: #2ecc71;
    color: white;
    border: none;
    padding: 8px 15px;
    font-size: 14px;
    border-radius: 4px;
    cursor: pointer;
    margin-bottom: 20px;
    display: inline-block;
}

.secondary-btn:hover {
    background-color: #27ae60;
}

.range-controls {
    display: flex;
    gap: 30px;
    flex-wrap: wrap;
    margin-top: 10px;
    padding-top: 15px;
    border-top: 1px solid #dee2e6;
}

.input-group {
    margin-bottom: 15px;
    display: flex;
    align-items: center;
    flex-wrap: wrap;
    gap: 10px;
}

.input-group label {
    font-weight: 600;
    min-width: 80px;
}

input[type="number"] {
    padding: 8px;
    width: 80px;
    border: 1px solid #ced4da;
    border-radius: 4px;
}

#draw-btn {
    background-color: #3498db;
    color: white;
    border: none;
    padding: 10px 20px;
    font-size: 16px;
    border-radius: 4px;
    cursor: pointer;
    transition: background-color 0.2s;
    width: 100%;
    margin-top: 10px;
}

#draw-btn:hover {
    background-color: #2980b9;
}

.canvas-container {
    position: relative;
    /* height: 500px; function-plot 会自动控制高度 */
    width: 100%;
    margin-top: 20px;
}

.instructions {
    margin-top: 30px;
    padding: 15px;
    background-color: #e8f4fd;
    border-radius: 8px;
    border-left: 4px solid #3498db;
}

.instructions h3 {
    margin-top: 0;
    font-size: 16px;
}

.instructions ul {
    margin-bottom: 0;
    padding-left: 20px;
}

.instructions li {
    margin-bottom: 5px;
}

code {
    background-color: #fff;
    padding: 2px 5px;
    border-radius: 3px;
    font-family: monospace;
    color: #e74c3c;
}