style.css

*{
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body{
    background-image: linear-gradient(120deg,#f6d365,#d88771);
    color: white;
    font-family: Poppins;
    min-height: 100vh;
}

header{
    font-size: 1.5rem;
}

header, form{
    min-height: 20vh;
    display: flex;
    justify-content: center;
    align-items: center;
}

form input, form button{
    padding: 0.5rem;
    font-size: 2rem;
    border: none;
    background: white;
}

form button{
    color: #d88771;
    background: white;
    cursor: pointer;
    transition: all 0.3s ease;
}

form button:hover{
    background: #d88771;
    color: white;
}

.todo-container{
    display: flex;
    justify-content: center;
    align-items: center;
}
.todo-list{
    min-width: 30%;
    list-style: none;
}
.todo{
    margin: 0.5rem;
    background: white;
    color: black;
    font-size: 1.5;
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: all 0.5s ease;
}
.todo li{
    flex: 1;
}
.delete-btn,
.completed-btn{
    background: #ff6f47;
    color: white;
    border: none;
    padding: 1rem;
    cursor: pointer;
    font-size: 1rem;
}
.completed-btn{
    background: rgb(73,204,73);
}
.todo-item{
    padding:0rem 0.5rem;
}
.fas{
    pointer-events: none;
}

.completed{
    text-decoration: line-through;
    opacity: 0.5;
}
.fall{
    transform: translateY(8rem) rotateZ(20deg);
    opacity: 0;
}

select{
    -webkit-appearance: none;
    appearance: none;
    outline: none;
    border: none ;
}
.select{
    margin: 1rem;
    position: relative;
    overflow: hidden;
}
select{
    color: #ff6f47;
    width: 10rem;
    cursor: pointer;
    padding: 1rem;
}
.select::after{
    content: "\25BC";
    position: absolute;
    background: #ff6f47;;
    top: 0;
    right: 0;
    padding: 1rem;
    pointer-events: none;
    transition: all 1.3s ease;
}
.select:hover::after{
    background:white;
    color: #ff6f47;
}