:root {
    --primary: #2c3e50;
    --secondary: #3498db;
}

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

body {
    font-family: 'Segoe UI', system-ui;
    line-height: 1.6;
    padding: 1rem;
    max-width: 1200px;
    margin: 0 auto;
}

.calculator {
    background: #f8f9fa;
    padding: 2rem;
    border-radius: 10px;
    box-shadow: 0 2px 15px rgba(0,0,0,0.1);
}

.unit-switcher {
    margin: 1rem 0;
    text-align: right;
}

.unit-switcher select {
    padding: 0.5rem;
    border-radius: 5px;
    border: 2px solid #ddd;
    font-size: 1rem;
}

.imperial-inputs { 
    display: none; 
}

.input-group {
    margin-bottom: 1.5rem;
}

label {
    display: block;
    margin-bottom: 0.5rem;
    color: var(--primary);
    font-weight: 600;
}

input {
    width: 100%;
    padding: 0.8rem;
    border: 2px solid #ddd;
    border-radius: 5px;
    font-size: 1rem;
}

button {
    background: var(--secondary);
    color: white;
    border: none;
    padding: 1rem 2rem;
    border-radius: 5px;
    cursor: pointer;
    width: 100%;
    font-size: 1.1rem;
    transition: opacity 0.3s;
}

button:hover {
    opacity: 0.9;
}

.result {
    margin-top: 2rem;
    padding: 1.5rem;
    background: #e9f5ff;
    border-radius: 5px;
    display: none;
}

@media (min-width: 768px) {
    .shape-sections {
        display: grid;
        grid-template-columns: repeat(2, 1fr);
        gap: 2rem;
    }
}