body {
    min-height: 100vh;
    margin: 0;
    padding: 0;
    background: linear-gradient(to right, #232526, #414345);
    display: flex;
    align-items: center;
    justify-content: center;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

.container {
    background: linear-gradient(to right, #141e30, #243b55);
    padding: 25px;
    border-radius: 5px;
    height: auto;
    width: 480;
    text-align: center;
    align-items: center;
}

.container h1 {
    color: white;
}

#add-task-btn {
    background: linear-gradient(to right, #667eea, #764ba2);
    padding: 5px;
    border: none;
    border-radius: 3px;
    color: white;
    height: 35px;
}

#todo-input {
    padding: 5px;
    margin: 5px;
    background-color: rgb(221, 214, 214);
    border: none;
    border-radius: 5px;
    height: 20px;
}

#todo-list {
    list-style: none;
    padding: 0;
    margin: 0;
    padding-top: 15px;
    width: 100%;
    height: auto;
}

#todo-list li {
    background: linear-gradient(to right, #232526, #414345);
    color: #fff;
    text-align: left;
    padding: 10px;
    border-radius: 3px;
    margin-bottom: 10px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    cursor: pointer;
    border-radius: 5px;
}

li.completed {
    text-decoration: line-through;
    opacity: 0.7;
}

li button {
    background: linear-gradient(to right, #1e3c72, #2a5298);
    border: none;
    padding: 5px;
    color: white;
    border-radius: 5px;
    cursor: pointer;
    margin-left: 10px;
}

li button:hover {
    background-color: #b71c1c;
}