:root {
    --primary: #4361ee;
    --secondary: #3a0ca3;
    --success: #4cc9f0;
    --light: #f8f9fa;
    --dark: #212529;
    --gray: #6c757d;
    --border-radius: 8px;
    --box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    --transition: all 0.3s ease;
}

* {
    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%);
    color: var(--dark);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 2rem 1rem;
}

.container {
    width: 100%;
    max-width: 800px;
    background-color: white;
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    padding: 2rem;
    margin-bottom: 2rem;
}

header {
    text-align: center;
    margin-bottom: 2rem;
}

h1 {
    color: var(--primary);
    margin-bottom: 0.5rem;
    font-size: 2.5rem;
}

.subtitle {
    color: var(--gray);
    font-size: 1.1rem;
}

.calculator {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1.5rem;
}

@media (max-width: 768px) {
    .calculator {
        grid-template-columns: 1fr;
    }
}

.input-group {
    margin-bottom: 1.5rem;
}

label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 600;
    color: var(--dark);
}

input {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid #ddd;
    border-radius: var(--border-radius);
    font-size: 1rem;
    transition: var(--transition);
}

input:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(67, 97, 238, 0.2);
}

.score-options {
    display: flex;
    gap: 1rem;
}

.score-btn {
    flex: 1;
    padding: 0.75rem;
    background-color: #e9ecef;
    border: none;
    border-radius: var(--border-radius);
    cursor: pointer;
    text-align: center;
    font-weight: 600;
    transition: var(--transition);
}

.score-btn:hover {
    background-color: #dee2e6;
}

.score-btn.active {
    background-color: var(--primary);
    color: white;
}

button {
    grid-column: span 2;
    padding: 1rem;
    background-color: var(--primary);
    color: white;
    border: none;
    border-radius: var(--border-radius);
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
}

@media (max-width: 768px) {
    button {
        grid-column: span 1;
    }
}

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

.results {
    margin-top: 2rem;
    padding-top: 2rem;
    border-top: 1px solid #eee;
}

.result-item {
    display: flex;
    justify-content: space-between;
    margin-bottom: 1rem;
    padding: 1rem;
    background-color: #f8f9fa;
    border-radius: var(--border-radius);
}

.result-label {
    font-weight: 600;
}

.result-value {
    font-weight: 700;
    color: var(--primary);
}

.gain-positive {
    color: #2ecc71;
}

.gain-negative {
    color: #e74c3c;
}

.explanation {
    margin-top: 2rem;
    padding: 1.5rem;
    background-color: #eef7ff;
    border-radius: var(--border-radius);
    border-left: 4px solid var(--primary);
}

.explanation h3 {
    margin-bottom: 1rem;
    color: var(--primary);
}

footer {
    text-align: center;
    color: var(--gray);
    font-size: 0.9rem;
}