.container {
    max-width: 600px;
    margin: 20px auto;
    padding: 20px;
    background: #fff;
    border-radius: 8px;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
}
.todo-container {
    padding: 20px;
    border: 1px solid #ccc;
    border-radius: 8px;
    margin-bottom: 20px;
}
.todo-container h1 {
    font-size: 2em;
    text-align: center;
    color: #333;
    margin-bottom: 20px;
}
.input-group {
    display: flex;
    flex-direction: column;
    gap: 10px;
    margin-bottom: 10px;
}
.input-group input {
    padding: 10px;
    font-size: 1em;
    border: 1px solid #ccc;
    border-radius: 4px;
    flex: 1;
}
.input-group .date-time {
    display: flex;
    gap: 10px;
    flex: 1;
    align-items: center;
}
.input-group .date-time input[type="date"] {
    flex: 0.66;
}
.input-group .date-time input[type="time"] {
    flex: 0.5;
}
.input-group .reminder {
    display: flex;
    align-items: center;
    margin-top: 10px;
    width: 100%;
}
.reminder label {
    margin-right: 5px;
}
.reminder input {
    width: auto;
    flex: none;
}
.add-button {
    padding: 10px;
    font-size: 1em;
    cursor: pointer;
    background-color: #007BFF;
    color: white;
    border: none;
    border-radius: 4px;
    width: 100%;
}
.add-button:hover {
    background-color: #0056b3;
}
.todo-list-container {
    padding: 20px;
    border: 1px solid #ccc;
    border-radius: 8px;
}
.todo-list-header {
    display: flex;
    justify-content: space-between;
    padding: 10px;
    background: #f1f1f1;
    border-bottom: 2px solid #ccc;
    font-weight: bold;
}
.todo-list-header span {
    flex: 1;
    text-align: left;
    margin-left: 10px;
}
.todo-list-header span.due-date {
    flex: 0.4;
}
.todo-list-header span.due-time {
    flex: 0.3;
}
.todo-list-header span.reminder {
    flex: 0.2;
}
.todo-list {
    list-style-type: none;
    padding: 0;
}
.todo-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 10px;
    border-bottom: 1px solid #ccc;
    border-radius: 4px;
    margin-bottom: 10px;
}
.todo-item button {
    background-color: transparent;
    color: black;
    border: none;
    cursor: pointer;
    border-radius: 4px;
    padding: 5px 10px;
    flex: 0.1;
}
.todo-item button:hover {
    color: darkred;
}
.message {
    color: red;
    font-size: 1em;
    text-align: center;
    margin-top: 10px;
}