.action-buttons {
    display: flex;
    gap: 16px;
    width: 100%;
}

.action-btn {
    flex: 1;
    width: 100%;
    height: 64px;
    border-radius: 14px;
    border: none;
    font-size: 22px;
    font-weight: 800;
    letter-spacing: 2px;
    color: #fff;
    cursor: pointer;
    transition: .15s;
}

.action-btn.start {
    background: linear-gradient(135deg, #2ecc71, #27ae60);
}

.action-btn.end {
    background: linear-gradient(135deg, #ff7675, #d63031);
}

.action-btn:disabled {
    background: #cfcfcf;
    color: #9e9e9e;
    cursor: not-allowed;
}