body {
    margin: 0;
    font-family: Arial, sans-serif;
    background: #f3f4f6;
    display: flex;
    justify-content: center;
    padding: 24px;
}

.container {
    width: 100%;
    max-width: 700px;
    background: white;
    border-radius: 16px;
    padding: 24px;
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.08);
}

h2 {
    margin-bottom: 20px;
    font-size: 22px;
    color: #1f2937;
}

.card {
    border: 1px solid #e5e7eb;
    border-radius: 12px;
    padding: 16px;
    margin-bottom: 16px;
    background: #fff;
}

.card h3 {
    margin: 0 0 12px 0;
    font-size: 16px;
    color: #374151;
}

.grid-2 {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 10px;
}

.grid-3 {
    display: grid;
    grid-template-columns: 1fr 1fr 1fr;
    gap: 10px;
}

input {
    width: 100%;
    padding: 10px;
    border: 1px solid #d1d5db;
    border-radius: 8px;
    outline: none;
    font-size: 14px;
}

input:focus {
    border-color: #3b82f6;
    box-shadow: 0 0 0 2px rgba(59, 130, 246, 0.2);
}

label {
    font-weight: 600;
    color: #374151;
    display: block;
    margin-bottom: 6px;
}

.full {
    width: 100%;
}

button {
    width: 100%;
    padding: 12px;
    background: #2563eb;
    color: white;
    font-weight: 600;
    border: none;
    border-radius: 12px;
    cursor: pointer;
    transition: 0.2s;
    font-size: 15px;
}

button:hover {
    background: #1d4ed8;
}

#result {
    margin-top: 20px;
    font-size: 18px;
    font-weight: 600;
    color: #111827;
}