* {
    box-sizing: border-box;
}

html,
body {
    margin: 0;
    padding: 0;
}

body {
    font-family: Arial, Helvetica, sans-serif;
    color: #222;
    background: #fff;
    line-height: 1.5;
}

.tool-container {
    max-width: 850px;
    padding: 24px;
}

.tool-header h1 {
    margin: 0 0 8px;
    font-size: 30px;
}

.tool-header p {
    margin: 0;
    color: #555;
}

.calculator-section,
.info-section {
    margin-top: 30px;
    padding-top: 22px;
    border-top: 2px solid #333;
}

.calculator-section h2,
.info-section h2 {
    margin: 0 0 6px;
}

.section-description {
    margin-top: 0;
    color: #555;
}

.input-grid {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 16px;
    margin: 20px 0;
}

.input-grid.three-column {
    grid-template-columns: repeat(3, minmax(0, 1fr));
}

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

.field label {
    font-weight: bold;
}

.field input,
.field select {
    width: 100%;
    padding: 10px;
    font: inherit;
    border: 1px solid #aaa;
    border-radius: 4px;
}

.unit-field {
    max-width: 260px;
    margin-bottom: 20px;
}

button {
    padding: 11px 18px;
    font: inherit;
    font-weight: bold;
    cursor: pointer;
    border: 1px solid #333;
    border-radius: 4px;
    background: #f3f3f3;
}

button:hover {
    background: #e7e7e7;
}

.results {
    margin-top: 22px;
    padding: 18px;
    border: 1px solid #ccc;
    border-radius: 5px;
    background: #fafafa;
}

.results h3 {
    margin: 0 0 12px;
}

.result-row {
    display: flex;
    justify-content: space-between;
    gap: 20px;
    padding: 9px 0;
    border-bottom: 1px solid #ddd;
}

.result-row:last-child {
    border-bottom: 0;
}

.result-row strong {
    text-align: right;
}

.formula {
    margin: 18px 0;
    padding: 14px;
    border-left: 4px solid #333;
    background: #f5f5f5;
    font-weight: bold;
}

@media (max-width: 650px) {
    .tool-container {
        padding: 16px;
    }

    .input-grid,
    .input-grid.three-column {
        grid-template-columns: 1fr;
    }

    .tool-header h1 {
        font-size: 26px;
    }
}