/* General Reset & Body Styling */
* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

:root {
    --bg-color: #f4f4f4;
    --text-color: #333;
    --card-bg-color: #fff;
    --border-color: #ddd;
    --header-bg-color: #2c3e50;
    --header-text-color: #ecf0f1;
    --link-color: #2980b9;
    --instruction-bg-color: #ecf0f1;
    --instruction-border-color: #3498db;
}

html[data-theme='dark'] {
    --bg-color: #2d3436;
    --text-color: #dfe6e9;
    --card-bg-color: #636e72;
    --border-color: #444;
    --header-bg-color: #1e272e;
    --header-text-color: #ecf0f1;
    --link-color: #74b9ff;
    --instruction-bg-color: #485460;
    --instruction-border-color: #74b9ff;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--bg-color);
    display: flex;
    flex-direction: column;
    min-height: 100vh;
    transition: background-color 0.3s, color 0.3s;
}

.container {
    max-width: 800px;
    margin: 2rem auto;
    padding: 0 2rem;
    flex: 1;
}

/* Header & Footer */
header {
    background-color: var(--header-bg-color);
    color: var(--header-text-color);
    padding: 2rem;
    text-align: center;
}

header h1 {
    margin-bottom: 0.5rem;
}

header a {
    color: inherit;
    text-decoration: none;
}

footer {
    background-color: #34495e;
    color: #ecf0f1;
    text-align: center;
    padding: 1rem;
    margin-top: auto;
}

/* Main Content & Test Scenarios */
.test-case {
    background-color: var(--card-bg-color);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 2rem;
    margin-bottom: 2rem;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}

.test-case h2 {
    margin-top: 0;
    color: var(--header-bg-color);
    border-bottom: 2px solid #e0e0e0;
    padding-bottom: 0.5rem;
    margin-bottom: 1rem;
}

.instructions {
    background-color: var(--instruction-bg-color);
    border-left: 4px solid var(--instruction-border-color);
    padding: 1rem;
    margin-bottom: 1.5rem;
    font-size: 0.95rem;
}

.scenario-list, .scenario-list-soon {
    list-style: none;
    padding-left: 0;
}

.scenario-list li, .scenario-list-soon li {
    background: var(--card-bg-color);
    padding: 1rem;
    border: 1px solid var(--border-color);
    margin-bottom: 0.5rem;
    border-radius: 5px;
}

.scenario-list a {
    text-decoration: none;
    color: var(--link-color);
    font-weight: bold;
}

.scenario-list a:hover {
    text-decoration: underline;
}

.scenario-list-soon li {
    color: #777;
    background-color: #f9f9f9;
}

/* Form Elements & Buttons */
.form-group {
    margin-bottom: 1rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: bold;
}

.form-group input[type="text"],
.form-group input[type="password"],
.form-group input[type="file"],
.form-group input[type="date"],
.form-group input[type="email"],
.form-group textarea,
.form-group select {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid #ccc;
    border-radius: 4px;
    font-size: 1rem;
}

.form-group textarea {
    resize: vertical;
    min-height: 100px;
}

.form-group input[type="radio"],
.form-group input[type="checkbox"] {
    margin-right: 0.5rem;
}

.btn {
    display: inline-block;
    background-color: #3498db;
    color: #fff;
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    font-size: 1rem;
    text-align: center;
    text-decoration: none;
    margin-right: 0.5rem;
    margin-bottom: 0.5rem;
}

.btn:hover {
    background-color: #2980b9;
}

.btn-secondary {
    background-color: #95a5a6;
}

.btn-secondary:hover {
    background-color: #7f8c8d;
}

/* Validation & Output */
#output {
    margin-top: 1.5rem;
    padding: 1rem;
    border-radius: 5px;
    font-family: "Courier New", Courier, monospace;
    font-size: 0.9rem;
    background-color: #2d3436;
    color: #dfe6e9;
    border: 1px solid #444;
    min-height: 50px;
    white-space: pre-wrap;
    word-wrap: break-word;
}

.validation-message {
    padding: 1rem;
    border-radius: 5px;
    margin-top: 1.5rem;
    font-weight: bold;
    display: none; /* Hidden by default */
}

.validation-message.success {
    background-color: #d4edda;
    color: #155724;
    border: 1px solid #c3e6cb;
    display: block;
}

.validation-message.error {
    background-color: #f8d7da;
    color: #721c24;
    border: 1px solid #f5c6cb;
    display: block;
}

/* Dynamic Content Specific */
#content-area {
    padding: 1rem;
    border: 2px dashed #ccc;
    min-height: 100px;
    margin-top: 1rem;
    display: flex;
    align-items: center;
    justify-content: center;
}

/* Mouse Interactions */
.hover-container {
    background-color: #3498db;
    color: white;
    padding: 1rem;
    text-align: center;
    cursor: pointer;
    width: 200px;
    margin-bottom: 1rem;
}
.hover-reveal {
    display: none;
    margin-top: 0.5rem;
    background-color: #2980b9;
    padding: 0.5rem;
    border-radius: 4px;
}
.hover-container:hover .hover-reveal {
    display: block;
}

#draggable {
    width: 100px;
    height: 100px;
    background-color: #e74c3c;
    color: white;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: grab;
    margin-bottom: 1rem;
}
#droppable {
    width: 200px;
    height: 200px;
    border: 3px dashed #95a5a6;
    display: flex;
    align-items: center;
    justify-content: center;
    color: #95a5a6;
}
#droppable.hover {
    background-color: #ecf0f1;
    border-color: #2ecc71;
}
#droppable.dropped {
    background-color: #d4edda;
    border-color: #2ecc71;
    color: #155724;
}

/* Iframe */
iframe {
    width: 100%;
    height: 250px;
    border: 1px solid #ddd;
}

/* Dynamic Table */
table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 1rem;
}
th, td {
    border: 1px solid #ddd;
    padding: 0.75rem;
    text-align: left;
}
th {
    background-color: #f2f2f2;
}

/* Infinite Scroll */
#scroll-container {
    height: 400px;
    overflow-y: scroll;
    border: 1px solid #ddd;
    padding: 1rem;
    background-color: #fff;
}
.scroll-item {
    padding: 1rem;
    background-color: #ecf0f1;
    margin-bottom: 1rem;
    border-radius: 4px;
}

/* Shadow DOM */
#shadow-host {
    border: 2px dashed #3498db;
    padding: 1.5rem;
    background-color: #f0f8ff;
}

/* Horizontal Slider */
.slider-container {
    display: flex;
    align-items: center;
    margin-top: 1rem;
}

#slider {
    width: 80%;
    margin-right: 1rem;
}

#slider-value {
    font-weight: bold;
    font-size: 1.2rem;
    color: #2c3e50;
    min-width: 40px;
}

/* Modals */
.modal {
    display: none; /* Hidden by default */
    position: fixed;
    z-index: 1000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    overflow: auto;
    background-color: rgba(0,0,0,0.5);
}
.modal-content {
    background-color: #fefefe;
    margin: 15% auto;
    padding: 20px;
    border: 1px solid #888;
    width: 80%;
    max-width: 500px;
    border-radius: 8px;
    position: relative;
}
.modal-header {
    padding-bottom: 1rem;
    border-bottom: 1px solid #e0e0e0;
    margin-bottom: 1rem;
}
.modal-close {
    color: #aaa;
    float: right;
    font-size: 28px;
    font-weight: bold;
    cursor: pointer;
}
.modal-close:hover,
.modal-close:focus {
    color: black;
}

/* Autocomplete */
.autocomplete-container {
    position: relative;
}
.autocomplete-items {
    position: absolute;
    border: 1px solid #d4d4d4;
    border-bottom: none;
    border-top: none;
    z-index: 99;
    top: 100%;
    left: 0;
    right: 0;
}
.autocomplete-items div {
    padding: 10px;
    cursor: pointer;
    background-color: #fff;
    border-bottom: 1px solid #d4d4d4;
}
.autocomplete-items div:hover {
    background-color: #e9e9e9;
}

/* Tabs & Accordions */
.tabs-container {
    border: 1px solid #ddd;
    border-radius: 5px;
    overflow: hidden;
}
.tab-buttons {
    display: flex;
    background-color: #f1f1f1;
}
.tab-btn {
    background-color: inherit;
    border: none;
    outline: none;
    cursor: pointer;
    padding: 14px 16px;
    transition: 0.3s;
    font-size: 1rem;
    flex-grow: 1;
}
.tab-btn:hover {
    background-color: #ddd;
}
.tab-btn.active {
    background-color: #ccc;
}
.tab-content {
    display: none;
    padding: 1rem;
    border-top: 1px solid #ddd;
}
.tab-content.active {
    display: block;
}

.accordion-item {
    border: 1px solid #ddd;
    margin-bottom: -1px; /* Prevent double borders */
}
.accordion-item:first-child {
    border-top-left-radius: 5px;
    border-top-right-radius: 5px;
}
.accordion-item:last-child {
    margin-bottom: 0;
    border-bottom-left-radius: 5px;
    border-bottom-right-radius: 5px;
}
.accordion-header {
    background-color: #f1f1f1;
    color: #444;
    cursor: pointer;
    padding: 1rem;
    width: 100%;
    border: none;
    text-align: left;
    outline: none;
    font-size: 1rem;
    transition: 0.4s;
}
.accordion-header:hover, .accordion-header.active {
    background-color: #ddd;
}
.accordion-content {
    padding: 0 1rem;
    background-color: white;
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.2s ease-out;
}
.accordion-content p {
    padding: 1rem 0;
}

/* Sorting & Filtering */
th.sortable {
    cursor: pointer;
    position: relative;
}
th.sortable::after {
    content: '\2195'; /* Up-down arrow */
    position: absolute;
    right: 8px;
    color: #ccc;
}
th.sortable.sorted-asc::after {
    content: '\2191'; /* Up arrow */
    color: #333;
}
th.sortable.sorted-desc::after {
    content: '\2193'; /* Down arrow */
    color: #333;
}

/* Multi-step Form */
.form-step {
    display: none;
}
.form-step.active {
    display: block;
}
.progress-bar {
    display: flex;
    justify-content: space-between;
    margin-bottom: 2rem;
    list-style: none;
    padding: 0;
}
.progress-step {
    text-align: center;
    position: relative;
    flex: 1;
    color: #95a5a6;
}
.progress-step::before {
    content: '';
    position: absolute;
    top: 50%;
    left: -50%;
    transform: translateY(-50%);
    height: 2px;
    width: 100%;
    background-color: #e0e0e0;
    z-index: -1;
}
.progress-step:first-child::before {
    display: none;
}
.progress-step.active {
    color: #3498db;
    font-weight: bold;
}
.progress-step.active::before {
    background-color: #3498db;
}

/* Login Page */
.login-container {
    max-width: 400px;
    margin: 2rem auto;
    padding: 2rem;
    background: #fff;
    border-radius: 8px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}

/* Dashboard */
.dashboard-welcome {
    background-color: #d4edda;
    color: #155724;
    padding: 1rem;
    border-radius: 5px;
    border: 1px solid #c3e6cb;
}

/* AJAX Content */
#ajax-content-placeholder {
    border: 2px dashed #ccc;
    padding: 2rem;
    margin-top: 1rem;
    min-height: 100px;
    background-color: #f9f9f9;
    text-align: center;
    color: #777;
}
#ajax-content-placeholder.loaded {
    border-style: solid;
    border-color: #2ecc71;
    background-color: #d4edda;
    color: #155724;
}

/* Error Handling */
.form-group .error-message {
    color: #e74c3c;
    font-size: 0.875rem;
    margin-top: 0.25rem;
    display: none; /* Hidden by default */
}
.form-group input.invalid {
    border-color: #e74c3c;
}

/* Canvas */
#drawing-canvas {
    border: 2px solid #2c3e50;
    cursor: crosshair;
    background-color: #fff;
}

/* SVG */
#clickable-svg {
    cursor: pointer;
    max-width: 200px;
}
#clickable-svg .svg-shape:hover {
    opacity: 0.8;
}

/* Internationalization */
.lang-switcher {
    margin-bottom: 1.5rem;
}

/* Rich Text Editor */
.editor-toolbar {
    background-color: #f1f1f1;
    padding: 8px;
    border: 1px solid #ccc;
    border-bottom: none;
    border-radius: 4px 4px 0 0;
}
.editor-toolbar button {
    background: #fff;
    border: 1px solid #ccc;
    padding: 5px 10px;
    margin-right: 5px;
    cursor: pointer;
    font-weight: bold;
}
.editor-content {
    border: 1px solid #ccc;
    padding: 1rem;
    min-height: 150px;
    border-radius: 0 0 4px 4px;
    background-color: #fff;
}

/* Pagination */
.pagination-container {
    margin-top: 2rem;
    text-align: center;
}
.pagination-container a {
    color: #3498db;
    padding: 8px 16px;
    text-decoration: none;
    border: 1px solid #ddd;
    margin: 0 4px;
    border-radius: 4px;
}
.pagination-container a.active {
    background-color: #3498db;
    color: white;
    border-color: #3498db;
}
.pagination-container a:hover:not(.active) {
    background-color: #f1f1f1;
}

/* Performance */
#layout-shift-ad {
    background-color: #f8d7da;
    color: #721c24;
    padding: 1rem;
    text-align: center;
    display: none;
}

/* WebSockets */
#chat-container {
    display: flex;
    flex-direction: column;
    height: 300px;
}
#chat-messages {
    flex-grow: 1;
    border: 1px solid #ccc;
    padding: 1rem;
    overflow-y: auto;
    background: #fff;
    margin-bottom: 1rem;
}
#chat-messages .message {
    margin-bottom: 0.5rem;
}
#chat-messages .message.sent {
    text-align: right;
    color: #2980b9;
}
#chat-messages .message.received {
    text-align: left;
    color: #2c3e50;
}
#chat-form {
    display: flex;
}
#chat-input {
    flex-grow: 1;
    margin-right: 1rem;
}

/* Accessibility */
.contrast-example {
    padding: 1rem;
    border: 1px solid #ddd;
    margin-bottom: 1rem;
}
.contrast-good {
    background-color: #2c3e50;
    color: white;
}
.contrast-bad {
    background-color: #3498db;
    color: #ecf0f1;
}

/* Print styles */
@media print {
    body {
        background-color: #fff;
        color: #000;
    }
    header, footer, .instructions, .btn, #print-button {
        display: none;
    }
    .container, .test-case {
        max-width: 100%;
        margin: 0;
        padding: 0;
        border: none;
        box-shadow: none;
    }
    #printable-content h2 {
        font-size: 18pt;
    }
}

/* Media Elements */
.media-controls {
    margin-top: 1rem;
}