* {
    box-sizing: border-box;
    font-family: system-ui, -apple-system, 'Segoe UI', Roboto, 'Helvetica Neue', sans-serif;
}

body {
    background: #f0f4f8;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    margin: 20px;
}

.card {
    max-width: 800px;
    width: 100%;
    background: white;
    border-radius: 32px;
    padding: 32px 28px;
    box-shadow: 0 20px 40px rgba(0, 20, 40, 0.12);
    transition: all 0.2s ease;
}

h1 {
    font-size: 1.9rem;
    font-weight: 600;
    margin-top: 0;
    margin-bottom: 12px;
    color: #0b2b3b;
    display: flex;
    align-items: center;
    gap: 8px;
}

h1 span {
    background: #e1ecf4;
    padding: 5px 12px;
    font-size: 0.9rem;
    border-radius: 40px;
    color: #1b5e7a;
    font-weight: 400;
}

hr {
    border: none;
    border-top: 2px solid #dde7f0;
    margin: 24px 0 20px 0;
}

.method-row {
    background: #f2f6fa;
    border-radius: 60px;
    display: inline-flex;
    padding: 4px;
    margin-bottom: 32px;
}

.method-option {
    padding: 10px 28px;
    border-radius: 40px;
    font-weight: 500;
    cursor: pointer;
    transition: 0.1s;
    user-select: none;
    border: none;
    background: transparent;
    font-size: 1rem;
    color: #365f74;
}

.method-option.active {
    background: white;
    box-shadow: 0 4px 10px rgba(0, 30, 60, 0.08);
    color: #0f3b4c;
    font-weight: 600;
}

.grid-2 {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 18px 24px;
    margin-bottom: 24px;
}

.field-group {
    display: flex;
    flex-direction: column;
    gap: 6px;
}

.field-group label {
    font-weight: 600;
    font-size: 0.9rem;
    color: #1d4e66;
    letter-spacing: 0.02em;
    display: flex;
    align-items: center;
    gap: 5px;
}

.field-group input, .field-group select {
    background: #f9fcff;
    border: 1.5px solid #cbd6e4;
    border-radius: 18px;
    padding: 12px 16px;
    font-size: 1rem;
    outline: none;
    transition: 0.15s;
    width: 100%;
}

.field-group input:focus, .field-group select:focus {
    border-color: #1e7e9f;
    background: white;
    box-shadow: 0 0 0 3px rgba(22, 129, 173, 0.2);
}

.field-group.hidden {
    display: none;
}

.fuel-info-note {
    font-size: 0.8rem;
    color: #556c7c;
    margin-top: 2px;
    margin-left: 12px;
}

.result-block {
    background: linear-gradient(145deg, #e4eff9, #d1e2f0);
    border-radius: 28px;
    padding: 22px 30px;
    margin: 30px 0 10px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 20px;
}

.result-label {
    font-size: 1.3rem;
    font-weight: 500;
    color: #0c3a4b;
}

.result-value {
    font-size: 2.6rem;
    font-weight: 700;
    background: white;
    padding: 8px 32px;
    border-radius: 80px;
    color: #005072;
    line-height: 1.2;
    box-shadow: inset 0 -2px 5px rgba(0, 0, 0, 0.02);
}

.result-unit {
    font-size: 1rem;
    font-weight: 400;
    color: #2f5f74;
    margin-left: 5px;
}

.footnote {
    font-size: 0.85rem;
    color: #406277;
    display: flex;
    gap: 18px;
    flex-wrap: wrap;
    margin-top: 10px;
}

.badge {
    background: #dbe9f3;
    padding: 2px 15px;
    border-radius: 30px;
    font-size: 0.9rem;
}

button {
    background: none;
    border: none;
    color: #1a6f8d;
    font-weight: 600;
    cursor: pointer;
    font-size: 0.95rem;
    text-decoration: underline dotted;
    text-underline-offset: 4px;
}

button:hover {
    color: #023147;
}