```css
/* ==========================================
   GLOBAL STYLES
   ========================================== */

.control-bar {
    display: flex !important;
    background: red !important;
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    padding: 20px;
    font-family: Arial, sans-serif;
    background-color: #f5f5f5;
    color: #333;
}

.container {
    width: 100%;
    max-width: 900px;
    margin: 0 auto;
}

h1 {
    text-align: center;
    margin-bottom: 25px;
}

h2 {
    margin-top: 0;
    margin-bottom: 20px;
}

h3 {
    margin-bottom: 10px;
}


/* ==========================================
   CARDS
   ========================================== */

.card {
    background-color: #fff;
    padding: 20px;
    margin-bottom: 20px;
    border-radius: 8px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}


/* ==========================================
   FILE INPUT
   ========================================== */

input[type="file"] {
    display: block;
    width: 100%;
    margin-bottom: 10px;
}


/* ==========================================
   GENERAL BUTTONS
   ========================================== */

button {
    padding: 10px 16px;
    border: none;
    border-radius: 5px;
    background-color: #007bff;
    color: white;
    cursor: pointer;
    font-size: 14px;
    margin-top: 10px;
}

button:hover {
    background-color: #0056b3;
}


/* ==========================================
   OUTPUT GROUP
   ========================================== */

.output-group {
    margin-top: 20px;
}

.output-group > label {
    display: block;
    margin-bottom: 5px;
    font-weight: bold;
}


/* ==========================================
   BASE64 TEXTAREAS
   ========================================== */

textarea {
    display: block;
    width: 100%;
    max-width: 100%;
    min-height: 120px;
    padding: 10px;
    border: 1px solid #ccc;
    border-radius: 5px;
    resize: vertical;
    font-family: monospace;
    font-size: 13px;
    line-height: 1.5;
}


/* ==========================================
   CONTROL BAR
   ========================================== */

/*
   IMPORTANT:
   The checkbox stays on the LEFT.
   The Copy button is pushed completely
   to the RIGHT using margin-left: auto.
*/

.output-group > .control-bar {
    display: flex !important;
    flex-direction: row !important;
    align-items: center !important;
    justify-content: flex-start !important;

    width: 100% !important;
    max-width: 100% !important;

    margin: 10px 0 6px 0 !important;
    padding: 0 !important;

    box-sizing: border-box !important;
}


/* ==========================================
   REMOVE PREFIX CHECKBOX
   ========================================== */

.output-group > .control-bar > .checkbox-label {
    display: inline-flex !important;
    flex-direction: row !important;
    align-items: center !important;

    width: auto !important;
    max-width: none !important;

    margin: 0 !important;
    padding: 0 !important;

    font-size: 13px;
    font-weight: normal;

    color: #555;

    cursor: pointer;
    user-select: none;

    flex: 0 0 auto !important;
}


/* Checkbox itself */

.output-group > .control-bar > .checkbox-label input[type="checkbox"] {
    display: inline-block !important;

    width: 15px !important;
    min-width: 15px !important;
    max-width: 15px !important;

    height: 15px !important;
    min-height: 15px !important;
    max-height: 15px !important;

    margin: 0 10px 0 0 !important;
    padding: 0 !important;

    cursor: pointer;
}


/* Remove prefix text */

.output-group > .control-bar > .checkbox-label span {
    display: inline-block !important;

    width: auto !important;
    margin: 0 !important;
    padding: 0 0 0 2px !important;

    font-weight: normal;
}


/* ==========================================
   COPY BUTTON
   ========================================== */

.output-group > .control-bar > #copyBtn {
    display: inline-flex !important;

    /*
       THIS IS WHAT PUSHES THE BUTTON
       ALL THE WAY TO THE RIGHT.
    */
    margin-left: auto !important;

    margin-top: 0 !important;
    margin-right: 0 !important;
    margin-bottom: 0 !important;

    padding: 6px 8px !important;

    width: auto !important;
    min-width: 0 !important;
    max-width: none !important;

    height: auto !important;

    flex: 0 0 auto !important;
    align-self: center !important;

    align-items: center !important;
    justify-content: center !important;

    border: none;
    border-radius: 4px;

    background-color: #6c757d;

    color: white;

    cursor: pointer;

    line-height: 1 !important;
}


/* Copy button hover */

.output-group > .control-bar > #copyBtn:hover {
    background-color: #5a6268;
}


/* Copy icon */

.output-group > .control-bar > #copyBtn svg {
    display: block !important;

    width: 14px !important;
    height: 14px !important;

    margin: 0 !important;
    padding: 0 !important;

    pointer-events: none;
}


/* ==========================================
   PREVIEW
   ========================================== */

.preview-group {
    margin-top: 20px;
}

#imagePreview {
    display: block;
    max-width: 100%;
    height: auto;
    margin-top: 10px;
    border-radius: 5px;
}


/* ==========================================
   STATUS TEXT
   ========================================== */

#statusText {
    margin-top: 10px;
}


/* ==========================================
   MOBILE
   ========================================== */

@media (max-width: 600px) {

    body {
        padding: 10px;
    }

    .card {
        padding: 15px;
    }

    h1 {
        font-size: 24px;
    }

    h2 {
        font-size: 20px;
    }

}
```