:root {
    --primary-color: #4361ee;
    --secondary-color: #3f37c9;
    --accent-color: #4895ef;
    --text-color: #2b2d42;
    --light-color: #f8f9fa;
    --error-color: #ef233c;
}

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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    color: var(--text-color);
}

.container {
    width: 100%;
    max-width: 500px;
    padding: 20px;
}

.calculator-card {
    background: white;
    border-radius: 15px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    padding: 30px;
    transition: transform 0.3s ease;
}

.calculator-card:hover {
    transform: translateY(-5px);
}

.header {
    text-align: center;
    margin-bottom: 25px;
}

.header h1 {
    color: var(--primary-color);
    font-size: 28px;
    margin-bottom: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
}

.header p {
    color: #6c757d;
    font-size: 14px;
}

.input-group {
    margin-bottom: 20px;
}

.input-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 500;
    color: var(--text-color);
    display: flex;
    align-items: center;
    gap: 8px;
}

.input-group input {
    width: 100%;
    padding: 12px 15px;
    border: 2px solid #e9ecef;
    border-radius: 8px;
    font-size: 16px;
    transition: all 0.3s;
}

.input-group input:focus {
    border-color: var(--accent-color);
    outline: none;
    box-shadow: 0 0 0 3px rgba(72, 149, 239, 0.2);
}

.calculate-btn {
    width: 100%;
    padding: 14px;
    background: var(--primary-color);
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
}

.calculate-btn:hover {
    background: var(--secondary-color);
    transform: translateY(-2px);
}

.result-container {
    margin-top: 30px;
    display: none;
    animation: fadeIn 0.5s ease;
}

.result-card {
    display: flex;
    justify-content: space-between;
    background: linear-gradient(135deg, #4361ee 0%, #3a0ca3 100%);
    padding: 20px;
    border-radius: 10px;
    color: white;
    margin-bottom: 20px;
}

.result-item {
    text-align: center;
}

.value {
    font-size: 32px;
    font-weight: 700;
    display: block;
}

.unit {
    font-size: 14px;
    opacity: 0.9;
}

.additional-info {
    text-align: center;
}

.additional-info p {
    margin-bottom: 8px;
    font-size: 15px;
}

.error-message {
    color: var(--error-color);
    font-size: 14px;
    margin-top: 5px;
    display: none;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

@media (max-width: 480px) {
    .calculator-card {
        padding: 20px;
    }
    
    .result-card {
        flex-direction: column;
        gap: 15px;
    }
}