body {
    font-family: system-ui, sans-serif;
    background: linear-gradient(135deg, #5f2c82, #49a09d);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    flex-direction: column;
}

.app {
    width: 300px;
    padding: 20px;
    border-radius: 8px;
    background-color: white;
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.3);
}

h1 {
    font-size: 2.5rem;
}

#date {
    text-align: center;
}

.field-input {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

#habitInput {
    padding: 10px;
    font-size: 16px;
}

#addBtn {
    padding: 10px 20px;
    cursor: pointer;
}

#habitList {
    list-style: none;
    padding: 0;
}

#habitList li {
    border-top: 1px solid #ccc;
    padding: 8px;
    display: flex;
    justify-content: space-between;
}

#habitList li.completed {
    text-decoration: line-through;
    color: #555;
    opacity: 0.7;
}

.delete-btn,
.mark-btn {
    background: none;
    cursor: pointer;
    border: none;
    font-size: 18px;
}

.delete-btn:hover,
.mark-btn:hover {
    opacity: 0.6;
}