body {
    font-family: 'Segoe UI', Arial, sans-serif;
    margin: 0;
    padding: 0;
    background: linear-gradient(135deg, #34e5f9, #3b54de);
    color: #fff;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    text-align: center;
}

.header-container {
    margin-top: 120px;
}

h1 {
    font-size: 3rem;
    font-weight: bold;
}

.header-container p {
    font-size: 1.1rem;
    opacity: 0.9;
    margin-bottom: 30px;
}

.todo-container {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 10px;
}

ul#tasks {
    list-style-type: none;
    padding: 0;
    margin-bottom: 20px;
    width: 300px;
    text-align: left;
}

ul#tasks li {
    background: rgba(255, 255, 255, 0.15);
    padding: 8px 12px;
    margin-bottom: 5px;
    border-radius: 6px;
}

input[type="text"] {
    width: 220px;
    padding: 10px;
    border-radius: 8px;
    border: none;
    font-size: 1rem;
}

input[type="submit"].btn {
    padding: 10px 20px;
    border-radius: 8px;
    border: none;
    background: white;
    color: #3b54de;
    font-weight: bold;
    cursor: pointer;
}

.back-link {
    margin-top: auto;
    margin-bottom: 20px;
}

.back-link a {
    color: #fff;
    opacity: 0.8;
    text-decoration: none;
    transition: 0.2s;
}

.back-link a:hover {
    opacity: 1;
}

footer {
    background: rgba(255, 255, 255, 0.1);
    padding: 10px;
    font-size: 0.9rem;
}