side bar slideOut animation doesn't execute at all

Question

I am implementing my own React SideBar component. I am able to make it slide in but unable to make it slide out. fade-out executed but slide-out didn't. I really have no idea why. Please help! Thanks in advance.

This is the simplified AccountSideBar.tsx code:

import React, {useState} from 'react';
import './AccountSideBar.css';

interface AccountSideBarProps {
    onClose: () => void;
}

const AccountSideBar: React.FC<AccountSideBarProps> = ({ onClose }) => {
    const [isClosing, setIsClosing] = useState(false);

    const handleClose = () => {
        setIsClosing(true);
        setTimeout(onClose, 300);
    };

    return (
        <div className={`sidebar-overlay ${isClosing ? 'fade-out' : ''}`} onClick={handleClose}>
            <div className={`account-sidebar ${isClosing ? 'slide-out' : ''}`} onClick={(e) => e.stopPropagation()}>
                <div>
                    <button className="close-button" onClick={handleClose}>×</button>
                </div>
            </div>
        </div>
    );
};

export default AccountSideBar;

This is the App.css:

.sidebar-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-color: rgba(0, 0, 0, 0.5);
  z-index: 1000;
  display: flex;
  justify-content: flex-end;
  animation: fadeIn 0.3s ease-in-out;
}

.fade-out {
  animation: fadeOut 0.3s forwards;
}

.slide-out {
  animation: slideOut 0.3s forwards;
}

@keyframes fadeIn {
  from {
    background-color: rgba(0, 0, 0, 0);
  }
  to {
    background-color: rgba(0, 0, 0, 0.5);
  }
}

@keyframes fadeOut {
  from {
    background-color: rgba(0, 0, 0, 0.5);
  }
  to {
    background-color: rgba(0, 0, 0, 0);
  }
}

@keyframes slideIn {
  from {
    transform: translateX(100%);
  }
  to {
    transform: translateX(0);
  }
}

@keyframes slideOut {
  from {
    transform: translateX(0);
  }
  to {
    transform: translateX(100%);
  }
}

This is the AccountSideBar.css:

.account-sidebar {
    width: 300px;
    height: 100%;
    color: #fff;
    box-shadow: -2px 0 5px rgba(0, 0, 0, 0.5);
    display: flex;
    flex-direction: column;
    padding: 20px;
    animation: slideIn 0.3s ease-in-out;
}

.account-sidebar .close-button {
    position: absolute;
    top: 10px;
    right: 10px;
    background: none;
    border: none;
    color: #fff;
    font-size: 36px;
    cursor: pointer;
}

---Update---

I made a terrible mistake. To simplify question, I put the code from AccountSideBar.css and App.css together, not noticing that this would cause confusion.

Answer 1

The issue you are encountering is related to CSS specificity. Both .account-sidebar and .slide-out are of the same selector type, giving them equal specificity. In such cases, the style defined later will override the earlier one. To resolve this, simply move the .slide-out class below the .account-sidebar in your CSS, and it should work as expected. like this

.sidebar-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-color: rgba(0, 0, 0, 0.5);
  z-index: 1000;
  display: flex;
  justify-content: flex-end;
}

.fade-out {
  animation: fadeOut 0.3s forwards;
}

@keyframes fadeIn {
  from {
    background-color: rgba(0, 0, 0, 0);
  }
  to {
    background-color: rgba(0, 0, 0, 0.5);
  }
}

@keyframes fadeOut {
  from {
    background-color: rgba(0, 0, 0, 0.5);
  }
  to {
    background-color: rgba(0, 0, 0, 0);
  }
}

@keyframes slideIn {
  from {
    transform: translateX(100%);
  }
  to {
    transform: translateX(0);
  }
}

@keyframes slideOut {
  from {
    transform: translateX(0);
  }
  to {
    transform: translateX(100%);
  }
}
.account-sidebar {
  width: 300px;
  height: 100%;
  color: #fff;
  box-shadow: -2px 0 5px rgba(0, 0, 0, 0.5);
  display: flex;
  flex-direction: column;
  padding: 20px;
  animation: slideIn 0.3s ease-in-out;
}

.slide-out {
  animation: slideOut 0.3s forwards;
}

.account-sidebar .close-button {
  position: absolute;
  top: 10px;
  right: 10px;
  background: none;
  border: none;
  color: #fff;
  font-size: 36px;
  cursor: pointer;
}