* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    padding: 20px;
}

.container {
    max-width: 800px;
    margin: 0 auto;
    background: white;
    padding: 30px;
    border-radius: 15px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2);
}

h1 {
    text-align: center;
    color: #333;
    margin-bottom: 10px;
}

p {
    text-align: center;
    color: #666;
    margin-bottom: 30px;
}

.input-group {
    margin-bottom: 20px;
}

label {
    display: block;
    margin-bottom: 5px;
    font-weight: bold;
    color: #333;
}

input {
    width: 100%;
    padding: 12px;
    border: 2px solid #ddd;
    border-radius: 8px;
    font-size: 16px;
    transition: border-color 0.3s;
}

input:focus {
    outline: none;
    border-color: #667eea;
}

button {
    width: 100%;
    padding: 15px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 16px;
    font-weight: bold;
    cursor: pointer;
    transition: transform 0.2s;
}

button:hover {
    transform: translateY(-2px);
}

.results {
    margin-top: 30px;
    padding: 20px;
    background: #f8f9fa;
    border-radius: 10px;
}

.hidden {
    display: none;
}

#roots {
    font-size: 18px;
    margin-bottom: 20px;
    text-align: center;
    font-weight: bold;
}

.chart-container {
    position: relative;
    height: 400px;
    margin-top: 20px;
}

.error {
    background: #fee;
    color: #c33;
    padding: 15px;
    border-radius: 8px;
    margin-top: 20px;
    border: 1px solid #fcc;
}