styles.css

*{
    margin: 0;
    padding: 0;
    outline: 0;
    border: none;
    box-sizing: border-box;
    font-family: 'Roboto', sans-serif;

}
html{
    font-size: 62.5%;
    font-family: 'Roboto', sans-serif;
}
body{
    font-size: 16px;
    background-color: rgba(0, 0, 0, 0.125);;
}
header{
    background-color: #FF5F5D;
    width: 100%;
    height: 250px;
    text-align: center;
    padding: 5rem 0;
    color: #fff;
}
.container{
    display: flex;
    justify-content: center;
    margin-top: -8%;
}
.form {
    background-color: #fff;
    max-width: 440px;
    height: 500px;
    width: 100%;
    padding: 2.4rem;
    border-radius: 4px;
    box-shadow: 0 12px 30px rgba(0, 0, 0, 0.08);
}
.btn{
    background-color: #00CCBF;
    padding: 12px 24px;
    cursor: pointer;
    border-radius: 4px;
    color: #fff;
    font-weight: 700;
    transition: background 0.8s ease;
}
button:hover{
    background-color: #72F2EB
}
input[type="text"]{
    border: 1px solid #747E7E;
    height: 40px;
    padding-left: 8px;
    color: #000;
    width: 100%;
    border-radius: 4px;

}
.input {
    display: flex;
    gap: 8px;
    
}
.tasks{
    padding-top: 2.5rem;
}

.tasks .item{
    display: flex;
    justify-content: flex-start;
    align-items: center;
    gap: .8rem;
    height: 50px;
    border-top: 1px solid rgba(0, 0, 0, 0.078);
}
.tasks .item h3{
    width: 100%;
    font-size: 1.4rem;
}
input[type="checkbox"]:checked ~ h3{
    text-decoration: line-through;
}

.input-error {
    border: 1px solid red !important;
    color: red !important;
}