:root {
    color-scheme: dark;
    font-family: "Inter", "Segoe UI", sans-serif;
    background: radial-gradient(circle at top right, #0d1b2a 0%, #1b263b 50%, #415a77 100%);
}

body {
    margin: 0;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    color: #e0e6f0;
}

.container {
    background: rgba(13, 27, 42, 0.85);
    border-radius: 28px;
    box-shadow: 0 25px 60px rgba(7, 16, 30, 0.55);
    padding: 44px;
    width: min(92%, 620px);
    text-align: center;
    border: 1px solid rgba(65, 90, 119, 0.4);
}

header h1 {
    margin-bottom: 0.4rem;
    font-size: 2.5rem;
    color: #9cb4d8;
}

.description {
    margin-top: 0;
    color: #8aa0bf;
    font-size: 1rem;
}

.form-card {
    margin-top: 2rem;
    padding: 1.6rem;
    border-radius: 20px;
    background: rgba(27, 38, 59, 0.7);
    border: 1px solid rgba(88, 115, 158, 0.35);
}

label {
    display: block;
    text-align: left;
    font-weight: 600;
    color: #b5c7e5;
    margin-bottom: 1rem;
}

input[type="text"] {
    margin-top: 0.4rem;
    width: 100%;
    padding: 0.9rem 1rem;
    border-radius: 12px;
    border: 1px solid rgba(88, 115, 158, 0.4);
    background: rgba(15, 23, 42, 0.9);
    color: #f1f5f9;
    font-size: 1rem;
    transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

input[type="text"]:focus {
    outline: none;
    border-color: #9cb4d8;
    box-shadow: 0 0 0 4px rgba(156, 180, 216, 0.2);
}

button[type="submit"] {
    margin-top: 1.1rem;
    padding: 0.85rem 1.5rem;
    border-radius: 999px;
    border: none;
    font-weight: 700;
    color: #101720;
    background: linear-gradient(135deg, #9cb4d8, #5c7caa);
    cursor: pointer;
    transition: transform 0.15s ease, box-shadow 0.15s ease;
}

button[type="submit"]:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 22px rgba(92, 124, 170, 0.4);
}

.error {
    margin-top: 1rem;
    color: #f8b4b4;
    font-weight: 600;
}

.result-card {
    margin-top: 2.2rem;
    display: grid;
    gap: 1.5rem;
    padding: 1.9rem;
    border-radius: 20px;
    background: rgba(13, 27, 42, 0.85);
    border: 1px solid rgba(156, 180, 216, 0.3);
    box-shadow: inset 0 0 0 1px rgba(55, 75, 105, 0.25);
}

.result-card.empty {
    color: #9cb4d8;
    font-weight: 500;
}

.score-display {
    display: flex;
    align-items: baseline;
    justify-content: center;
    gap: 0.65rem;
    color: #8eb5ff;
}

.score-display .value {
    font-size: 3.6rem;
    font-weight: 800;
}

.score-display .unit {
    font-size: 1.2rem;
    font-weight: 600;
}

.message h2 {
    margin: 0 0 0.5rem;
    font-size: 1.7rem;
    color: #bcd2f2;
}

.message p {
    margin: 0;
    color: #9fb5d8;
}

@media (max-width: 600px) {
    .container {
        padding: 30px 22px;
    }

    header h1 {
        font-size: 2.1rem;
    }

    .score-display .value {
        font-size: 2.9rem;
    }
}