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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: #f0f4f8;
    display: flex;
    justify-content: center;
    align-items: flex-start;
    min-height: 100vh;
    padding: 20px;
}

.container {
    max-width: 1000px;
    width: 100%;
    background: white;
    padding: 30px;
    border-radius: 24px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.12);
}

h1 {
    font-size: 26px;
    font-weight: 600;
    color: #1a2634;
    display: flex;
    align-items: center;
    gap: 10px;
    flex-wrap: wrap;
    margin-bottom: 6px;
}

.subhead {
    color: #4a5b6e;
    font-size: 15px;
    border-left: 4px solid #3b82f6;
    padding-left: 14px;
    margin: 6px 0 24px 0;
    background: #f0f4ff;
    border-radius: 0 12px 12px 0;
    line-height: 1.5;
    padding: 10px;
}

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

.input-group {
    display: flex;
    flex-direction: column;
    gap: 4px;
    margin-bottom: 16px;
}

.input-group label {
    font-size: 13px;
    font-weight: 600;
    color: #2c3e50;
}

.input-group input {
    padding: 12px 14px;
    border-radius: 12px;
    border: 2px solid #e2e8f0;
    font-size: 16px;
    font-weight: 500;
    transition: 0.15s;
    background: white;
    width: 100%;
}

.input-group input:focus {
    outline: none;
    border-color: #3b82f6;
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.2);
}

.result-container {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.result-box {
    background: #0b1e2f;
    border-radius: 18px;
    padding: 24px;
    display: flex;
    flex-direction: column;
    gap: 16px;
    color: white;
}

.result-item {
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.result-item .label {
    font-size: 11px;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    color: #8aa3c0;
}

.result-item .value {
    font-size: 28px;
    font-weight: 700;
    color: #fbbf24;
    font-family: 'Courier New', monospace;
}

.result-item .value.sub-value {
    color: #6ee7b7;
    font-size: 18px;
}

.formula-info {
    font-size: 13px;
    color: #64748b;
    background: #eff6ff;
    padding: 15px;
    border-radius: 12px;
    border-left: 4px solid #3b82f6;
    line-height: 1.5;
}

@media (max-width: 768px) {
    .grid-2col {
        grid-template-columns: 1fr;
    }
    .container {
        padding: 20px;
    }
}