.standart-sapma-calculator {
    --primary: #475569;
    --accent: #334155;
    --bg-light: #f8fafc;

    max-width: 800px;
    margin: 2rem auto;
    background: #fff;
    border-radius: 20px;
    padding: 3rem;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.05);
}

.standart-sapma-calculator .calculator-header h2 {
    color: var(--primary);
    font-weight: 800;
}

.standart-sapma-calculator textarea.form-control {
    border: 2px solid #e2e8f0;
    border-radius: 12px;
    padding: 1rem;
    font-size: 1.1rem;
    resize: none;
}

.standart-sapma-calculator .btn-primary {
    background: var(--primary);
    border: none;
    padding: 1rem 2rem;
    border-radius: 10px;
    font-weight: 700;
}

.stdev-grid {
    margin-top: 2rem;
}

.stdev-card {
    background: #fff;
    padding: 1.5rem;
    border-radius: 16px;
    border: 1px solid #e2e8f0;
    text-align: center;
}

.stdev-card.main {
    background: var(--primary);
    color: #fff;
    margin-bottom: 1.5rem;
    padding: 2.5rem;
}

.stdev-card.main .val {
    font-size: 3.5rem;
    font-weight: 900;
}

.stdev-card.main .label {
    font-size: 1rem;
    opacity: 0.9;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.stdev-sub-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1rem;
}

.stdev-card .label {
    font-size: 0.8rem;
    color: #64748b;
    margin-bottom: 0.5rem;
}

.stdev-card .val {
    font-size: 1.5rem;
    font-weight: 700;
    color: #1e293b;
}

.stats-info {
    background: #f1f5f9;
    padding: 1rem;
    border-radius: 8px;
    font-size: 0.9rem;
    color: #475569;
}

@media (max-width: 640px) {
    .stdev-sub-grid {
        grid-template-columns: 1fr;
    }

    .stdev-card.main .val {
        font-size: 2.5rem;
    }
}