body {
    font-family: 'Segoe UI', Arial, sans-serif;
    background: linear-gradient(135deg, #f8fafc 0%, #e0e7ef 100%);
    margin: 0;
    padding: 0;
    color: #222;
}

header {
    background: #0a2540;
    color: #fff;
    padding: 1.5rem 0;
    text-align: center;
}

header h1 {
    margin: 0;
    font-size: 2.2rem;
    letter-spacing: 1px;
}

nav {
    margin-top: 1rem;
}

nav a {
    color: #fff;
    text-decoration: none;
    margin: 0 1rem;
    font-weight: 500;
    transition: color 0.2s;
}

nav a:hover {
    color: #ffd700;
}

main {
    display: flex;
    justify-content: center;
    align-items: flex-start;
    min-height: 80vh;
    padding: 2rem 1rem;
}

.calculator-section {
    background: #fff;
    border-radius: 16px;
    box-shadow: 0 4px 24px rgba(10,37,64,0.08);
    padding: 2rem 2.5rem;
    max-width: 400px;
    width: 100%;
}

.calculator-section h2 {
    margin-top: 0;
    color: #0a2540;
    font-size: 1.4rem;
    margin-bottom: 1.5rem;
}

form label {
    display: block;
    margin-bottom: 1.2rem;
    font-weight: 500;
}

input, select {
    width: 100%;
    padding: 0.6rem;
    margin-top: 0.3rem;
    border: 1px solid #cbd5e1;
    border-radius: 6px;
    font-size: 1rem;
    box-sizing: border-box;
}

button {
    width: 100%;
    padding: 0.8rem;
    background: #0a2540;
    color: #fff;
    border: none;
    border-radius: 6px;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    margin-top: 1rem;
    transition: background 0.2s;
}

button:hover {
    background: #ffd700;
    color: #0a2540;
}

#result {
    margin-top: 2rem;
    font-size: 1.1rem;
    color: #0a2540;
    background: #f1f5f9;
    padding: 1rem;
    border-radius: 8px;
    min-height: 40px;
}

footer {
    background: #0a2540;
    color: #fff;
    text-align: center;
    padding: 1rem 0;
    font-size: 0.95rem;
    margin-top: 2rem;
}

@media (max-width: 600px) {
    .calculator-section {
        padding: 1.2rem 0.7rem;
        max-width: 100%;
    }
    main {
        padding: 1rem 0.2rem;
    }
}