style.css

*{
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}
body{
    height: 100vh;
    background: linear-gradient(90deg,pink 0%, rgb(255, 0, 255) 100%);
    display: flex;
    align-items: center;
    justify-content: center;
}

.container{
    border: 2px solid white;
    padding: 30px 40px;
    width: 40%;
    min-width: 500px;
}
.container h1{
    color:rgb(247, 228, 228);   
    text-align: center;
    margin-bottom: 20px;
    font-size: 3rem;
}

.new-task-container{
    background-color: white;
    padding: 30px 20px;
    border-radius: 5px;
    box-shadow: 0 15px 30px rgba(0, 0, 0, 0.3);
    display: flex;
}
.new-task-container input{
    flex: 3;
    font-size: 1rem;
    border: 2px solid #d1d3d4;
    border-radius: 5px;
    padding: 12px;
    font-weight: 500;
}

.new-task-container input:focus{
    outline: none;
    border-color: rgb(255, 0, 255);

}

.botaoadicionar{
    flex:1;
    border: none;
    background-color: pink;
    border-radius:5px ;
    padding: 12px;
    font-weight: 500;
    font-size: 1rem;
    margin-left: 12px;
    height: 100%;
    color: black;
    cursor: pointer;
}

.tasks-container{
    background-color: white;
    padding: 30px 20px;
    margin-top: 60px;
    border-radius: 5px;
    box-shadow: 0 15px 30px rgba(0, 0, 0, 0.3);
    width: 100%;
}

/*JS*/
.erro{
    border: 2px solid red !important;
}
.erro::placeholder{
    color: red;
}

.item-tarefa{
    display: flex;    
    align-items: center;
    margin-bottom: 15px;
    font-size: large  
}

.item-tarefa p {
   margin-top: 12px;
}

.item-tarefa i{
    background-color: pink;
    padding: 10px;
    border-radius: 5px;
    float:right;
    margin-left: auto;
}

.form-check:checked{
    background-color: pink;
}
.completed {
    text-decoration: line-through;
}

.texto{
    display: block;
}