body {
    font-family: Arial, sans-serif;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin: 0;
    background-color: #f0f0f0;
}

header.head {
    width: 100%;
    text-align: center;
    padding: 20px 0;
    background-color: #fff;
    border-bottom: 1px solid #ccc;
    position: fixed;
    top: 0;
    left: 0;
    z-index: 1000;
    font-size: 2rem;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
}

.flex-container {
    width: 100%;
    max-width: 600px;
    margin: 80px auto;
    padding: 20px;
    box-sizing: border-box;
}

#d1 {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 20px;
    background-color: #fff;
    border: 1px solid #ccc;
    border-radius: 10px;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
    margin-bottom: 20px;
}

#d1 input[type="text"] {
    width: 100%;
    max-width: 500px;
    padding: 10px;
    margin-bottom: 10px;
    border: 1px solid #ccc;
    border-radius: 5px;
    font-size: 1rem;
}

#d1 button {
    width: 100%;
    max-width: 200px;
    padding: 10px 20px;
    background-color: #5cb85c;
    color: #fff;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    font-size: 1rem;
}

#tasks {
    width: 100%;
    text-align: left;
    max-height: 200px;
    overflow-y: auto;
}

.task-item {
    background-color: #e3e7ec;
    border: 1px solid #ced4da;
    padding: 10px;
    margin-top: 10px;
    border-radius: 5px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 1rem;
}

.task-item button {
    padding: 5px 10px;
    background-color: #dc3545;
    color: #fff;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    font-size: 0.9rem;
    margin-left: 5px;
}

#mainbtn {
    position: fixed;
    bottom: 20px;
    right: 10px;
    border-radius: 50%;
    height: 70px;
    width: 70px;
    font-size: 2rem;
    background-color: #f63;
    border: none;
    color: #fff;
    cursor: pointer;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
    z-index: 1000;
}

@media (max-width: 768px) {
    .flex-container {
        margin: 40px auto;
        padding: 10px;
    }

    #d1 input[type="text"] {
        width: calc(100% - 20px);
        max-width: 100%;
    }

    #d1 button {
        width: 100%;
        max-width: 100%;
    }

    .task-item button {
        font-size: 0.8rem;
        padding: 3px 8px;
    }
}

@media (max-width: 480px) {
    header.head {
        font-size: 1.5rem;
    }

    .flex-container {
        margin: 20px auto;
    }

    #mainbtn {
        font-size: 1.5rem;
        height: 60px;
        width: 60px;
        bottom: 10px;
        right: 10px;
    }

    .task-item {
        font-size: 0.9rem;
    }

    .task-item button {
        font-size: 0.7rem;
        padding: 2px 6px;
    }
}