.formulas-header {
    text-align: center;
    margin-bottom: 2rem;
}
.formulas-header h1 {
    color: var(--primary-dark);
    font-size: 2rem;
    margin-bottom: 0.5rem;
}
.formulas-header p {
    color: var(--text-secondary);
    font-size: 1rem;
}
.formulas-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 1.5rem;
    margin-bottom: 3rem;
}
.formula-card {
    background: var(--bg-card);
    padding: 1.5rem;
    border-radius: 20px;
    text-align: center;
    box-shadow: var(--shadow-md);
    transition: all 0.3s ease;
    border-bottom: 4px solid #9b59b6;
    cursor: pointer;
}
.formula-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-hover);
}
.formula-number {
    background: linear-gradient(135deg, #9b59b6, #8e44ad);
    color: var(--text-white);
    width: 45px;
    height: 45px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 1rem auto;
    font-size: 1.3rem;
    font-weight: bold;
}
.formula-card h3 {
    color: var(--primary-dark);
    margin-bottom: 0.5rem;
    font-size: 1.1rem;
}
.formula-card p {
    color: var(--text-secondary);
    font-size: 0.85rem;
    margin-bottom: 1rem;
}
.formula-section {
    background: var(--bg-card);
    border-radius: 25px;
    padding: 1.5rem;
    margin-bottom: 2rem;
    box-shadow: var(--shadow-md);
}
.formula-section h2 {
    color: #e74c3c;
    margin-bottom: 1rem;
    border-right: 4px solid #e74c3c;
    padding-right: 1rem;
}
.formula-display {
    background: var(--bg-formula);
    padding: 1.5rem;
    border-radius: 15px;
    margin: 1rem 0;
    text-align: center;
    font-family: monospace;
    font-size: 1.2rem;
    overflow-x: auto;
}
.formula-list {
    list-style: none;
    padding: 0;
}
.formula-list li {
    background: var(--bg-card-hover);
    padding: 0.8rem 1rem;
    margin-bottom: 0.5rem;
    border-radius: 12px;
    border-right: 3px solid #e74c3c;
}
.formula-list li strong {
    color: #e74c3c;
}
.formula-list li span {
    font-family: monospace;
    font-size: 1.1rem;
}
.back-button {
    text-align: center;
    margin: 2rem 0;
}
.back-button a {
    display: inline-block;
    background: #2a5298;
    color: white;
    padding: 0.8rem 1.5rem;
    border-radius: 40px;
    text-decoration: none;
    transition: 0.3s;
}
.back-button a:hover {
    background: #e74c3c;
    transform: scale(1.05);
}
.formula-container {
    max-width: 1000px;
    margin: 0 auto;
    padding: 0 1rem;
}
.formula-divider {
    height: 2px;
    background: linear-gradient(90deg, transparent, var(--accent), transparent);
    margin: 2rem 0;
}
@media (max-width: 992px) {
    .formulas-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}
@media (max-width: 576px) {
    .formulas-grid {
        grid-template-columns: 1fr;
    }
    .formula-display {
        font-size: 1rem;
    }
}