* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: Arial, Helvetica, sans-serif;
}

body {
    background: linear-gradient(135deg, #667eea, #764ba2);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
}

.container {
    background: #fff;
    padding: 25px;
    border-radius: 12px;
    width: 90%;
    max-width: 400px;
    box-shadow: 0 10px 25px rgba(0,0,0,0.2);
    text-align: center;
}

h1 {
    margin-bottom: 20px;
    color: #333;
}

.input-section {
    display: flex;
    gap: 10px;
    margin-bottom: 20px;
}

.input-section input {
    flex: 1;
    padding: 10px;
    border: 2px solid #ddd;
    border-radius: 8px;
    outline: none;
    transition: 0.3s;
}

.input-section input:focus {
    border-color: #667eea;
}

.input-section button {
    padding: 10px 15px;
    border: none;
    background: #667eea;
    color: #fff;
    border-radius: 8px;
    cursor: pointer;
    transition: 0.3s;
}

.input-section button:hover {
    background: #5a67d8;
}

ul {
    list-style: none;
}

li {
    background: #f4f4f4;
    padding: 10px;
    border-radius: 8px;
    margin-bottom: 10px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

li.completed {
    text-decoration: line-through;
    color: gray;
}

.task-btns {
    display: flex;
    gap: 8px;
}

.task-btns button {
    border: none;
    padding: 5px 8px;
    border-radius: 5px;
    cursor: pointer;
}

.complete-btn {
    background: #48bb78;
    color: white;
}

.delete-btn {
    background: #f56565;
    color: white;
}

@media (max-width: 500px) {
    .container {
        padding: 15px;
    }

    h1 {
        font-size: 20px;
    }
}