.calc-tool-container {
    padding: 20px;
    max-width: 420px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    gap: 25px;
    margin-bottom: 80px;
}

.calc-header {
    text-align: center;
    margin-bottom: 20px;
}

.calc-header h2 {
    font-size: 2rem;
    color: var(--text-color);
    margin-bottom: 10px;
}

.calc-header p {
    color: var(--footer-text);
    font-size: 0.95rem;
}

.calc-workspace {
    background-color: var(--nav-bg);
    border: 1px solid var(--border-color);
    border-radius: 16px;
    padding: 20px;
    display: flex;
    flex-direction: column;
    gap: 20px;
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.05);
}

.calc-display-section {
    width: 100%;
}

.calc-display {
    width: 100%;
    height: 70px;
    padding: 15px;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    background-color: var(--bg-color);
    color: var(--text-color);
    font-size: 28px;
    text-align: left;
    font-family: monospace;
    outline: none;
    transition: border-color 0.3s;
}

.calc-buttons-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 12px;
}

.calc-btn {
    background-color: var(--bg-color);
    color: var(--text-color);
    border: 1px solid var(--border-color);
    padding: 18px;
    border-radius: 8px;
    font-size: 1.2rem;
    font-weight: 600;
    cursor: pointer;
    transition: background-color 0.2s, color 0.2s, border-color 0.2s;
    user-select: none;
}

.calc-btn:hover {
    background-color: var(--border-color);
}

.calc-btn.operator {
    color: var(--primary-color);
    font-weight: 700;
}

.calc-btn.clear {
    color: #ef4444;
}

.calc-btn.equal {
    grid-column: span 2;
    background-color: var(--primary-color);
    color: #ffffff;
    border-color: var(--primary-color);
}

.calc-btn.equal:hover {
    opacity: 0.9;
}

@media (max-width: 480px) {
    .calc-btn {
        padding: 14px;
        font-size: 1.1rem;
    }
}