/* style.css - Enhanced styling for the frontend */

/* --- Theme Variables --- */
:root {
    /* Light Theme Defaults */
    --bg-color: #e0f2f7; /* Overall background (soft gradient start) */
    --bg-color-end: #c5e1ee; /* Overall background (soft gradient end) */
    --header-bg-start: #34495e; /* Header background start */
    --header-bg-end: #2c3e50; /* Header background end */
    --header-text-color: #ffffff; /* Header text color */
    --card-bg: #ffffff; /* Card background (auth, chat section) */
    --chat-box-bg: #f5fafd; /* Chat messages box background */
    --message-bg: #ffffff; /* Default message background */
    --my-message-bg: #dcf8c6; /* My message background (light green) */
    --system-message-color: #6c757d; /* System message text color */
    --text-color: #333; /* General text color */
    --input-bg: #ffffff; /* Input field background */
    --input-border: #a7d9f0; /* Input field border */
    --input-focus-border: #007bff; /* Input focus border */
    --button-primary-bg-start: #28a745; /* Primary button background start (green) */
    --button-primary-bg-end: #218838; /* Primary button background end (green) */
    --button-primary-hover-bg-start: #218838; /* Primary button hover background start */
    --button-primary-hover-bg-end: #1e7e34; /* Primary button hover background end */
    --button-secondary-bg-start: #6c757d; /* Secondary button background start (grey) */
    --button-secondary-bg-end: #5a6268; /* Secondary button background end (grey) */
    --button-secondary-hover-bg-start: #5a6268; /* Secondary button hover background start */
    --button-secondary-hover-bg-end: #494f54; /* Secondary button hover background end */
    --button-info-bg-start: #007bff; /* Info button background start (blue) */
    --button-info-bg-end: #0056b3; /* Info button background end (blue) */
    --button-info-hover-bg-start: #0056b3; /* Info button hover background start */
    --button-info-hover-bg-end: #004085; /* Info button hover background end */
    --button-danger-bg-start: #dc3545; /* Danger button background start (red) */
    --button-danger-bg-end: #c82333; /* Danger button background end (red) */
    --button-danger-hover-bg-start: #c82333; /* Danger button hover background start */
    --button-danger-hover-bg-end: #bd2130; /* Danger button hover background end */
    --button-text-color: #ffffff; /* Button text color */
    --border-color: #e0e0e0; /* General border color */
    --box-shadow-light: rgba(0, 0, 0, 0.1); /* Light box shadow */
    --box-shadow-medium: rgba(0, 0, 0, 0.2); /* Medium box shadow */
    --box-shadow-strong: rgba(0, 0, 0, 0.3); /* Strong box shadow */
    --notification-info-bg: #2196F3;
    --notification-info-text: #ffffff;
    --notification-success-bg: #4CAF50;
    --notification-success-text: #ffffff;
    --notification-error-bg: #f44336;
    --notification-error-text: #ffffff;
    --reply-preview-bg: #f0f8ff; /* Background for reply preview */
    --reply-preview-border: #007bff; /* Border for reply preview */
    --reply-preview-text: #555;
    --reply-to-container-bg: #e6f7ff;
    --reply-to-container-border: #a7d9f0;
    --reply-to-container-border-left: #007bff;
    --username-color: #0056b3;
    --timestamp-color: #888;
    --selected-message-border: #007bff;
    --selected-message-bg: #e0f2ff;
    --online-indicator-color: #28a745; /* Green for online */
}

body.dark-theme {
    /* Soft Dark Theme Overrides (Brighter than previous dark) */
    --bg-color: #36454F; /* Charcoal Grey */
    --bg-color-end: #415A77; /* Darker Blue-Grey */
    --header-bg-start: #415A77;
    --header-bg-end: #36454F;
    --header-text-color: #E0E0E0; /* Light Grey */
    --card-bg: #4A607C; /* Medium Blue-Grey */
    --chat-box-bg: #36454F; /* Same as main background for cohesion */
    --message-bg: #5A7391; /* Slightly lighter message background */
    --my-message-bg: #6B8E23; /* Olive Green (still distinct) */
    --system-message-color: #B0C4DE; /* Light Steel Blue */
    --text-color: #E0E0E0; /* Light Grey */
    --input-bg: #4A607C; /* Same as card background */
    --input-border: #6B8E23; /* Olive Green for input borders */
    --input-focus-border: #6A5ACD; /* Slate Blue */
    --button-primary-bg-start: #6B8E23; /* Olive Green */
    --button-primary-bg-end: #556B2F; /* Dark Olive Green */
    --button-primary-hover-bg-start: #556B2F;
    --button-primary-hover-bg-end: #4B5320;
    --button-secondary-bg-start: #708090; /* Slate Grey */
    --button-secondary-bg-end: #607080;
    --button-secondary-hover-bg-start: #607080;
    --button-secondary-hover-bg-end: #506070;
    --button-info-bg-start: #6A5ACD; /* Slate Blue */
    --button-info-bg-end: #483D8B; /* Dark Slate Blue */
    --button-info-hover-bg-start: #483D8B;
    --button-info-hover-bg-end: #3A2F70;
    --button-danger-bg-start: #CD5C5C; /* Indian Red */
    --button-danger-bg-end: #B22222; /* Firebrick */
    --button-danger-hover-bg-start: #B22222;
    --button-danger-hover-bg-end: #8B0000;
    --button-text-color: #ffffff;
    --border-color: #5A7391; /* Medium Blue-Grey for borders */
    --box-shadow-light: rgba(0, 0, 0, 0.25);
    --box-shadow-medium: rgba(0, 0, 0, 0.45);
    --box-shadow-strong: rgba(0, 0, 0, 0.65);
    --notification-info-bg: #6A5ACD;
    --notification-info-text: #E0E0E0;
    --notification-success-bg: #6B8E23;
    --notification-success-text: #E0E0E0;
    --notification-error-bg: #CD5C5C;
    --notification-error-text: #ffffff;
    --reply-preview-bg: #5A7391; /* Slightly lighter than message bg */
    --reply-preview-border: #6A5ACD;
    --reply-preview-text: #B0C4DE;
    --reply-to-container-bg: #5A7391;
    --reply-to-container-border: #6B8E23;
    --reply-to-container-border-left: #6A5ACD;
    --username-color: #B0C4DE;
    --timestamp-color: #A9A9A9; /* Dark Grey */
    --selected-message-border: #6A5ACD;
    --selected-message-bg: #5A7391;
    --online-indicator-color: #6B8E23; /* Olive Green for online */
}

/* --- General Body Styles (using variables) --- */
body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, var(--bg-color) 0%, var(--bg-color-end) 100%); /* Soft gradient background */
    display: flex;
    flex-direction: column; /* Changed to column to stack header, main, footer */
    justify-content: flex-start; /* Align content from the start */
    align-items: center;
    min-height: 100vh;
    margin: 0;
    color: var(--text-color);
    line-height: 1.6;
    padding: 0; /* Remove body padding as header/footer will handle it */
    box-sizing: border-box;
    /* Adjusted padding-top to body for minimized fixed header */
    padding-top: 60px; /* Default padding for header height */
    transition: background 0.5s ease, color 0.5s ease; /* Smooth transition for theme change */
}

.container {
    padding: 30px;
    border-radius: 12px; /* More rounded corners */
    box-shadow: 0 12px 30px var(--box-shadow-medium); /* Stronger, softer shadow */
    width: 100%;
    max-width: 700px; /* Slightly wider max-width */
    text-align: center;
    box-sizing: border-box;
    border: 1px solid var(--border-color); /* Subtle border for container */
}

/* Specific styling for the main content container */
.container.main-content {
    background-color: var(--card-bg); /* Use card-bg for main content area */
}

/* Styles for the new header */
.app-header {
    background: linear-gradient(90deg, var(--header-bg-start) 0%, var(--header-bg-end) 100%); /* Dark blue gradient for header */
    color: var(--header-text-color); /* White text for header */
    padding: 10px 20px; /* Minimized padding */
    width: 100%;
    box-shadow: 0 4px 15px var(--box-shadow-strong); /* More prominent header shadow */
    text-align: center;
    position: fixed;
    top: 0;
    left: 0;
    z-index: 1000; /* Ensure header stays on top */
    display: flex; /* Use flexbox for header content */
    align-items: center;
    justify-content: space-between; /* Space out profile and tagline */
    transition: background 0.5s ease, color 0.5s ease; /* Smooth transition for theme change */
}

.header-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
    width: 100%;
    max-width: 700px; /* Match main container width */
    margin: 0 auto; /* Center content */
    padding: 0; /* Remove padding from this specific container to minimize height */
    box-shadow: none !important; /* Ensure no shadow */
    border: none !important; /* Ensure no border */
    background-color: transparent !important; /* Ensure it's transparent */
}

.app-header h1 { /* This H1 is for the main app title in header */
    color: var(--header-text-color);
    margin: 0; /* Remove default margins */
    font-size: 1.8em;
    text-shadow: 1px 1px 2px rgba(0,0,0,0.2);
    display: none; /* Hide main H1 for a more compact header, use profile area instead */
}

.app-header p { /* Tagline */
    margin: 0;
    font-size: 0.9em;
    opacity: 0.9;
    flex-grow: 1; /* Allow tagline to grow */
    text-align: right; /* Align tagline to the right */
}

.profile-area {
    display: flex;
    align-items: center;
    gap: 10px; /* Space between pic and username */
    color: var(--header-text-color);
    font-weight: 600;
}

.profile-pic {
    width: 40px;
    height: 40px;
    border-radius: 50%; /* Make it round */
    object-fit: cover; /* Ensure image covers the area */
    border: 2px solid var(--header-text-color); /* White border around profile pic */
    box-shadow: 0 0 5px var(--box-shadow-medium);
}

.header-username {
    font-size: 1.1em;
}

/* Position logout button in header */
.header-controls { /* Added this class to wrap header buttons for better layout */
    display: flex;
    align-items: center;
    gap: 10px; /* Space between buttons */
}

.app-header #logout-btn {
    padding: 8px 15px; /* Smaller padding for header button */
    font-size: 0.9em;
    background: linear-gradient(90deg, var(--button-danger-bg-start) 0%, var(--button-danger-bg-end) 100%); /* Red gradient */
    box-shadow: 0 2px 5px var(--box-shadow-medium);
    color: var(--button-text-color);
    border: none;
    border-radius: 6px;
    cursor: pointer;
    transition: background 0.3s ease, transform 0.2s ease, box-shadow 0.2s ease;
}
.app-header #logout-btn:hover {
    background: linear-gradient(90deg, var(--button-danger-hover-bg-start) 0%, var(--button-danger-hover-bg-end) 100%);
    transform: translateY(-2px);
    box-shadow: 0 4px 8px var(--box-shadow-strong);
}


/* Main content area */
.main-content {
    flex-grow: 1;
    width: 100%;
    max-width: 700px;
    padding: 30px;
    box-sizing: border-box;
}


h1 { /* This H1 is for the title inside the main content (Authentication/Chat Room) */
    color: var(--text-color);
    margin-bottom: 30px;
    font-size: 2.2em;
    font-weight: 700;
    transition: color 0.5s ease;
}

.card {
    background-color: var(--card-bg);
    padding: 25px;
    border-radius: 10px;
    margin-bottom: 25px;
    border: 1px solid var(--border-color);
    box-shadow: 0 4px 15px var(--box-shadow-light);
    transition: background-color 0.5s ease, border-color 0.5s ease, box-shadow 0.5s ease;
}

.card h2 {
    color: var(--text-color);
    margin-top: 0;
    margin-bottom: 20px;
    font-size: 1.8em;
    font-weight: 600;
    transition: color 0.5s ease;
}

input[type="text"],
input[type="password"],
.room-selection select,
.file-input {
    width: calc(100% - 22px);
    padding: 12px;
    margin-bottom: 15px;
    border: 1px solid var(--input-border);
    border-radius: 6px;
    font-size: 1em;
    box-sizing: border-box;
    background-color: var(--input-bg);
    color: var(--text-color);
    transition: border-color 0.3s ease, box-shadow 0.3s ease, background-color 0.5s ease, color 0.5s ease;
}

input[type="text"]:focus,
input[type="password"]:focus,
.room-selection select:focus,
.file-input:focus {
    border-color: var(--input-focus-border);
    box-shadow: 0 0 0 4px rgba(0, 123, 255, 0.35); /* This rgba value can be kept static or also made a variable */
    outline: none;
}

button {
    background: linear-gradient(90deg, var(--button-primary-bg-start) 0%, var(--button-primary-bg-end) 100%);
    color: var(--button-text-color);
    padding: 12px 25px;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    font-size: 1em;
    margin: 5px;
    transition: background 0.3s ease, transform 0.2s ease, box-shadow 0.2s ease;
    box-shadow: 0 3px 8px var(--box-shadow-light);
}

button:hover {
    background: linear-gradient(90deg, var(--button-primary-hover-bg-start) 0%, var(--button-primary-hover-bg-end) 100%);
    transform: translateY(-3px);
    box-shadow: 0 6px 15px var(--box-shadow-medium);
}

button.secondary-btn { /* Style for Upload Profile Pic button */
    background: linear-gradient(90deg, var(--button-secondary-bg-start) 0%, var(--button-secondary-bg-end) 100%);
}
button.secondary-btn:hover {
    background: linear-gradient(90deg, var(--button-secondary-hover-bg-start) 0%, var(--button-secondary-hover-bg-end) 100%);
}

button#join-room-btn {
    background: linear-gradient(90deg, var(--button-info-bg-start) 0%, var(--button-info-bg-end) 100%);
}

button#join-room-btn:hover {
    background: linear-gradient(90deg, var(--button-info-hover-bg-start) 0%, var(--button-info-hover-bg-end) 100%);
}

/* --- Chat Section Layout (NEW FLEXBOX CONTAINER) --- */
.chat-section {
    flex-grow: 1;
    display: flex; /* Make chat-section a flex container */
    flex-direction: column; /* Stack its children (chat-main-content) vertically */
    padding: 20px;
    max-width: 1000px; /* Increased max-width to accommodate sidebar */
    margin: 20px auto;
    background-color: var(--card-bg); /* Use card-bg for the main chat container */
    border-radius: 10px;
    box-shadow: 0 4px 15px var(--box-shadow-medium);
    height: calc(100vh - 150px); /* Adjust height to fit header and footer */
    box-sizing: border-box;
    transition: background-color 0.5s ease, box-shadow 0.5s ease;
}

.chat-main-content { /* NEW wrapper for chat box and online users sidebar */
    display: flex;
    flex-grow: 1; /* Allow it to take available height */
    gap: 20px; /* Space between chat box and sidebar */
}

.chat-box-wrapper { /* Existing chat content, now wrapped */
    display: flex;
    flex-direction: column;
    flex-grow: 1; /* Allow chat box to grow */
    min-width: 0; /* Allow content to shrink */
}

.messages-box {
    border: 1px solid var(--input-border);
    padding: 15px;
    height: 350px; /* Fixed height for scrollability */
    overflow-y: auto;
    margin-bottom: 15px;
    background-color: var(--chat-box-bg);
    color: var(--text-color);
    text-align: left;
    border-radius: 8px;
    box-shadow: inset 0 1px 5px var(--box-shadow-light);
    transition: background-color 0.5s ease, border-color 0.5s ease, color 0.5s ease, box-shadow 0.5s ease;
    flex-grow: 1; /* Allow messages box to fill available height */
}

.message {
    margin-bottom: 10px;
    padding: 10px 15px;
    border-radius: 10px;
    background-color: var(--message-bg);
    box-shadow: 0 2px 8px var(--box-shadow-light);
    word-wrap: break-word;
    position: relative;
    display: flex;
    align-items: flex-start;
    gap: 10px;
    transition: background-color 0.5s ease, box-shadow 0.5s ease, border 0.2s ease;
}

.message-profile-pic {
    width: 30px;
    height: 30px;
    border-radius: 50%;
    object-fit: cover;
    border: 1px solid var(--border-color);
    flex-shrink: 0;
}

.message-content {
    flex-grow: 1;
}

.message strong {
    color: var(--username-color);
    font-weight: 600;
    display: block;
    margin-bottom: 5px;
    transition: color 0.5s ease;
}

.message .timestamp {
    font-size: 0.7em;
    color: var(--timestamp-color);
    margin-left: 10px;
    float: right;
    position: absolute;
    bottom: 5px;
    right: 10px;
    transition: color 0.5s ease;
}

.message.system {
    font-style: italic;
    color: var(--system-message-color);
    text-align: center;
    background-color: var(--card-bg);
    border-left: 5px solid #ffc107; /* Warning yellow, can be a variable */
    padding: 12px;
    box-shadow: 0 2px 8px var(--box-shadow-light);
    transition: background-color 0.5s ease, color 0.5s ease;
}

/* New styles for uploaded files */
.chat-image {
    max-width: 100%;
    height: auto;
    display: block;
    margin-top: 10px;
    border-radius: 8px;
    box-shadow: 0 3px 10px var(--box-shadow-medium);
}

.chat-file-link {
    display: inline-block;
    margin-top: 10px;
    padding: 8px 12px;
    background-color: var(--reply-to-container-bg);
    border: 1px solid var(--reply-to-container-border);
    border-radius: 6px;
    color: var(--button-info-bg-start);
    text-decoration: none;
    font-weight: 600;
    transition: background-color 0.2s ease, box-shadow 0.2s ease, color 0.5s ease;
    box-shadow: 0 1px 5px var(--box-shadow-light);
}

.chat-file-link:hover {
    background-color: var(--button-info-hover-bg-start);
    color: var(--button-text-color);
    text-decoration: underline;
    box-shadow: 0 2px 8px var(--box-shadow-medium);
}


.hidden {
    display: none;
}

/* Notification Message Box */
#notification-message {
    position: fixed;
    top: 70px; /* Below the header */
    left: 50%;
    transform: translateX(-50%);
    color: white;
    padding: 10px 20px;
    border-radius: 5px;
    z-index: 1001;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.3s ease-in-out, visibility 0.3s ease-in-out;
    box-shadow: 0 4px 8px var(--box-shadow-medium);
    min-width: 250px;
    text-align: center;
}

#notification-message.show {
    opacity: 1;
    visibility: visible;
}
#notification-message.error {
    background-color: var(--notification-error-bg);
    color: var(--notification-error-text);
}
#notification-message.info {
    background-color: var(--notification-info-bg);
    color: var(--notification-info-text);
}
#notification-message.success {
    background-color: var(--notification-success-bg);
    color: var(--notification-success-text);
}


.room-selection {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 10px;
    margin-bottom: 20px;
    flex-wrap: wrap;
}

.room-selection label {
    font-weight: 600;
    color: var(--text-color);
    transition: color 0.5s ease;
}

.room-selection select {
    flex-grow: 1;
    max-width: 200px;
    margin-bottom: 0;
}

/* Input and Send button alignment - UPDATED FOR FILE INPUT */
.message-input-area {
    display: flex;
    flex-direction: column; /* Stack reply container, file input, message input */
    align-items: stretch; /* Stretch items to fill width */
    gap: 10px;
    margin-bottom: 15px;
}

#file-input {
    flex-grow: 1;
    min-width: 100px;
    margin-bottom: 0;
}

#message-input {
    flex-grow: 3;
    min-width: 150px;
    margin-right: 0;
    margin-bottom: 0;
}

#send-btn {
    width: auto;
    padding-left: 15px;
    padding-right: 15px;
    margin-bottom: 0;
    align-self: flex-end; /* Align send button to the right */
}

/* Reply-to container styling */
.reply-to-container {
    background-color: var(--reply-to-container-bg);
    border: 1px solid var(--reply-to-container-border);
    border-left: 4px solid var(--reply-to-container-border-left);
    padding: 8px 12px;
    border-radius: 8px;
    margin-bottom: 10px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 0.9em;
    color: var(--text-color);
    transition: background-color 0.5s ease, border-color 0.5s ease, color 0.5s ease;
}

.reply-to-container strong {
    color: var(--username-color);
    transition: color 0.5s ease;
}

.reply-to-container .cancel-reply-btn {
    background: none;
    border: none;
    color: var(--system-message-color);
    font-size: 1.2em;
    cursor: pointer;
    padding: 0 5px;
    transition: color 0.2s ease;
    box-shadow: none; /* Remove button shadow */
    margin: 0; /* Remove button margin */
}
.reply-to-container .cancel-reply-btn:hover {
    color: var(--button-danger-bg-start); /* Red on hover */
    transform: none; /* Prevent transform on hover */
    background: none; /* Prevent background change on hover */
}

/* Styling for replied message preview within a message */
.reply-preview {
    background-color: var(--reply-preview-bg);
    border-left: 3px solid var(--reply-preview-border);
    padding: 5px 10px;
    margin-bottom: 8px;
    border-radius: 5px;
    font-size: 0.85em;
    color: var(--reply-preview-text);
    word-wrap: break-word; /* Ensure long text wraps */
    transition: background-color 0.5s ease, border-color 0.5s ease, color 0.5s ease;
}

.reply-preview strong {
    color: var(--username-color);
    transition: color 0.5s ease;
}

.reply-preview .replied-text {
    display: block; /* Make replied text a block to wrap below "Replying to" */
    margin-top: 3px;
    font-style: italic;
    color: var(--system-message-color);
    transition: color 0.5s ease;
}


#send-btn-area { /* This is a new div to wrap message input and send button */
    display: flex;
    align-items: center;
    gap: 10px;
    width: 100%;
}
#send-btn-area #message-input {
    flex-grow: 1;
    margin-bottom: 0; /* Remove bottom margin from input here */
}
#send-btn-area #send-btn {
    margin-bottom: 0; /* Remove bottom margin from button here */
}


/* Styles for the new footer */
.app-footer {
    background: linear-gradient(90deg, var(--header-bg-end) 0%, var(--header-bg-start) 100%);
    color: var(--header-text-color);
    padding: 15px 20px;
    width: 100%;
    text-align: center;
    font-size: 0.9em;
    box-shadow: 0 -4px 15px var(--box-shadow-strong);
    margin-top: auto;
    transition: background 0.5s ease, color 0.5s ease;
}

.app-footer p {
    margin: 0;
    opacity: 0.9;
}

/* Specific styling for the footer container */
.app-footer .container {
    padding: 0 20px; /* Add horizontal padding to create space from edges */
    box-shadow: none !important;
    border: none !important;
    background-color: transparent !important;
    display: flex;
    flex-direction: row; /* Changed to row for side-by-side layout */
    justify-content: space-between; /* Pushes items to opposite ends */
    align-items: center; /* Vertically center items */
    gap: 10px; /* Space between copyright and social links if they wrap */
    flex-wrap: wrap; /* Allow wrapping on smaller screens */
}

/* Social media links styling */
.social-links {
    display: flex;
    gap: 15px; /* Space between icons */
    margin-top: 0; /* Remove top margin as it's now row */
}

.social-links a {
    color: var(--header-text-color);
    font-size: 1.8em; /* Adjusted icon size for Bootstrap Icons */
    transition: color 0.3s ease, transform 0.2s ease;
}

.social-links a:hover {
    color: var(--button-info-bg-start); /* Change color on hover */
    transform: translateY(-3px); /* Slight lift on hover */
}


/* Scroll-to-top button styles */
.scroll-to-top-btn {
    position: fixed;
    bottom: 20px;
    right: 20px;
    background-color: var(--button-info-bg-start);
    color: var(--button-text-color);
    border: none;
    border-radius: 50%;
    width: 50px;
    height: 50px;
    font-size: 2em;
    display: flex;
    justify-content: center;
    align-items: center;
    cursor: pointer;
    box-shadow: 0 4px 10px var(--box-shadow-medium);
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.3s ease-in-out, visibility 0.3s ease-in-out, background-color 0.5s ease;
    z-index: 999;
}

.scroll-to-top-btn.show {
    opacity: 1;
    visibility: visible;
}

.scroll-to-top-btn:hover {
    background-color: var(--button-info-hover-bg-start);
}

/* Chat header controls for profile pic upload button */
.chat-header-controls {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
    flex-wrap: wrap;
    gap: 10px;
}
.chat-header-controls h2 {
    margin: 0;
    flex-grow: 1;
    text-align: left;
}


/* Message Selection Styles */
.message.selected-message {
    border: 2px solid var(--selected-message-border); /* Border for selected messages */
    background-color: var(--selected-message-bg); /* Background for selected messages */
    border-radius: 10px; /* Keep consistent with message border-radius */
    padding: 10px 15px; /* Keep consistent with message padding */
}

#delete-selected-btn {
    background: linear-gradient(90deg, var(--button-danger-bg-start) 0%, var(--button-danger-bg-end) 100%); /* Red gradient */
    color: var(--button-text-color);
    border: none;
    padding: 10px 15px;
    border-radius: 6px;
    cursor: pointer;
    transition: background 0.3s ease, transform 0.2s ease, box-shadow 0.2s ease;
    box-shadow: 0 3px 8px var(--box-shadow-light);
}

#delete-selected-btn:hover {
    background: linear-gradient(90deg, var(--button-danger-hover-bg-start) 0%, var(--button-danger-hover-bg-end) 100%);
    transform: translateY(-2px);
    box-shadow: 0 4px 8px var(--box-shadow-medium);
}

#delete-selected-btn.hidden {
    display: none;
}

#cancel-selection-btn {
    background: linear-gradient(90deg, var(--button-secondary-bg-start) 0%, var(--button-secondary-bg-end) 100%); /* Grey gradient */
    color: var(--button-text-color);
    border: none;
    padding: 10px 15px;
    border-radius: 6px;
    cursor: pointer;
    transition: background 0.3s ease, transform 0.2s ease, box-shadow 0.2s ease;
    box-shadow: 0 3px 8px var(--box-shadow-light);
}

#cancel-selection-btn:hover {
    background: linear-gradient(90deg, var(--button-secondary-hover-bg-start) 0%, var(--button-secondary-hover-bg-end) 100%);
    transform: translateY(-2px);
    box-shadow: 0 4px 8px var(--box-shadow-medium);
}

#cancel-selection-btn.hidden {
    display: none;
}

#chat-action-buttons {
    display: flex;
    gap: 10px; /* Space between buttons */
    margin-top: 10px;
    justify-content: center; /* Center the buttons */
    padding-bottom: 10px; /* Add some padding at the bottom */
}

/* Theme Toggle Button Style */
#theme-toggle-btn {
    background: linear-gradient(90deg, var(--button-info-bg-start) 0%, var(--button-info-bg-end) 100%);
    color: var(--button-text-color);
    border: none;
    padding: 8px 12px;
    border-radius: 6px; /* Slightly rounded */
    cursor: pointer;
    transition: background 0.3s ease, transform 0.2s ease, box-shadow 0.2s ease;
    box-shadow: 0 2px 5px var(--box-shadow-light);
}

#theme-toggle-btn:hover {
    background: linear-gradient(90deg, var(--button-info-hover-bg-start) 0%, var(--button-info-hover-bg-end) 100%);
    transform: translateY(-2px);
    box-shadow: 0 4px 8px var(--box-shadow-medium);
}

/* --- Online Users Sidebar Styles --- */
.online-users-sidebar {
    width: 250px; /* Default width for the sidebar */
    background-color: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 10px;
    padding: 15px;
    box-shadow: 0 4px 15px var(--box-shadow-light);
    display: flex;
    flex-direction: column;
    flex-shrink: 0; /* Prevent sidebar from shrinking */
    transition: width 0.3s ease, padding 0.3s ease, background-color 0.5s ease, border-color 0.5s ease, box-shadow 0.5s ease;
    overflow: hidden; /* Hide content that overflows when minimized */
}

.online-users-header { /* NEW: Header for sidebar */
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 15px;
    padding-bottom: 10px;
    border-bottom: 1px solid var(--border-color);
    transition: border-color 0.5s ease;
}

.online-users-sidebar h3 {
    margin: 0;
    color: var(--text-color);
    font-size: 1.4em;
    white-space: nowrap; /* Prevent text wrapping */
    overflow: hidden; /* Hide overflow when minimized */
    text-overflow: ellipsis; /* Add ellipsis for overflow */
    transition: color 0.5s ease, opacity 0.3s ease;
}

.toggle-sidebar-btn { /* NEW: Style for the toggle button */
    background: none;
    border: none;
    color: var(--text-color);
    font-size: 1.5em;
    cursor: pointer;
    padding: 0 5px;
    line-height: 1; /* Ensure consistent height */
    transition: color 0.3s ease, transform 0.3s ease;
}

.toggle-sidebar-btn:hover {
    color: var(--button-info-bg-start);
}

/* Styles for minimized state */
.online-users-sidebar.minimized {
    width: 50px; /* Minimized width */
    padding: 15px 5px; /* Reduced padding */
}

.online-users-sidebar.minimized .online-users-header {
    justify-content: center; /* Center the toggle button */
    border-bottom: none; /* Remove border when minimized */
    margin-bottom: 0;
    padding-bottom: 0;
}

.online-users-sidebar.minimized h3 {
    display: none; /* Hide heading when minimized */
    opacity: 0;
}

.online-users-sidebar.minimized #online-users-list {
    display: none; /* Hide the list when minimized */
    opacity: 0;
    transition: opacity 0.3s ease;
}

.online-users-sidebar.minimized .toggle-sidebar-btn {
    transform: rotate(0deg); /* Ensure it points right */
}


#online-users-list {
    list-style: none;
    padding: 0;
    margin: 0;
    flex-grow: 1; /* Allow list to grow and scroll if needed */
    overflow-y: auto; /* Enable scrolling for long lists */
    transition: opacity 0.3s ease; /* Smooth transition for list appearance */
}

.online-user-item {
    display: flex;
    align-items: center;
    padding: 8px 0;
    border-bottom: 1px dashed var(--border-color); /* Subtle separator */
    color: var(--text-color);
    font-weight: 500;
    transition: color 0.5s ease, border-color 0.5s ease;
}

.online-user-item:last-child {
    border-bottom: none; /* No border for the last item */
}

.online-user-pic {
    width: 30px;
    height: 30px;
    border-radius: 50%;
    object-fit: cover;
    margin-right: 10px;
    border: 1px solid var(--border-color);
    flex-shrink: 0;
}

.online-username {
    flex-grow: 1;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.online-indicator {
    width: 10px;
    height: 10px;
    background-color: var(--online-indicator-color); /* Green dot for online */
    border-radius: 50%;
    margin-left: 10px;
    flex-shrink: 0;
}

.you-label {
    font-size: 0.8em;
    font-style: italic;
    color: var(--system-message-color);
    margin-left: 5px;
    flex-shrink: 0;
}


/* Responsive adjustments */
@media (max-width: 768px) {
    .container {
        padding: 15px;
        border-radius: 8px;
    }

    /* Adjust header for smaller screens */
    .app-header {
        padding: 8px 15px;
        flex-direction: column; /* Stack profile area and tagline */
        align-items: flex-start;
    }
    .app-header h1 {
        font-size: 1.5em;
    }
    .app-header p {
        font-size: 0.8em;
        text-align: left;
        width: 100%; /* Take full width */
    }
    /* Adjust logout button for smaller screens */
    .header-controls { /* Use this wrapper for responsive button stacking */
        width: 100%;
        flex-direction: column;
        align-items: stretch;
        gap: 8px; /* Reduce gap for stacked buttons */
        margin-top: 10px;
    }
    .app-header #logout-btn,
    #theme-toggle-btn { /* Apply to both header buttons */
        width: 100%;
        margin: 0; /* Remove individual margins */
        text-align: center;
    }


    /* Adjust body padding for smaller header */
    body {
        padding-top: 50px;
    }

    h1 {
        font-size: 1.8em;
        margin-bottom: 20px;
    }

    .card {
        padding: 15px;
        margin-bottom: 15px;
    }

    .card h2 {
        font-size: 1.5em;
        margin-bottom: 15px;
    }

    input[type="text"],
    input[type="password"],
    .room-selection select,
    .file-input,
    button {
        width: 100%;
        margin: 5px 0;
    }

    .room-selection {
        flex-direction: column;
        align-items: stretch;
    }

    .room-selection select {
        max-width: 100%;
    }

    .message-input-area {
        flex-direction: column;
        align-items: stretch;
        gap: 5px;
    }

    #file-input {
        width: 100%;
        margin-right: 0;
        margin-bottom: 5px;
    }
    #message-input {
        width: 100%;
        margin-right: 0;
        margin-bottom: 5px;
    }
    #send-btn {
        width: 100%;
        margin-bottom: 10px;
    }
    #send-btn-area {
        flex-direction: column;
        align-items: stretch;
    }


    .scroll-to-top-btn {
        width: 45px;
        height: 45px;
        font-size: 1.8em;
        bottom: 15px;
        right: 15px;
    }

    .chat-header-controls {
        flex-direction: column;
        align-items: flex-start;
    }
    .chat-header-controls h2 {
        text-align: center; /* Center chat room title on mobile */
        width: 100%;
    }

    /* --- Responsive for Online Users Sidebar --- */
    .chat-main-content {
        flex-direction: column; /* Stack chat box and sidebar vertically on smaller screens */
        gap: 15px;
    }

    .online-users-sidebar {
        width: 100%; /* Full width on smaller screens */
        order: -1; /* Place sidebar above chat box on mobile */
        padding: 15px; /* Reset padding for full width */
    }

    .online-users-sidebar.minimized {
        width: 100%; /* Still full width, but content hidden */
        padding: 15px; /* Keep padding */
    }

    .online-users-sidebar.minimized .online-users-header {
        justify-content: space-between; /* Keep space-between for mobile */
    }

    .online-users-sidebar.minimized h3 {
        display: block; /* Show heading on mobile even when minimized */
        opacity: 1;
        flex-grow: 1; /* Allow heading to take space */
        text-align: left;
    }


    /* Footer responsive adjustment */
    .app-footer .container {
        flex-direction: column; /* Stack on smaller screens */
        text-align: center;
    }
    .social-links {
        margin-top: 10px; /* Add back margin when stacked */
        justify-content: center; /* Center social links when stacked */
    }
}

@media (max-width: 480px) {
    body {
        padding: 10px;
        padding-top: 45px;
    }
    .container {
        padding: 15px;
    }
    h1 {
        font-size: 1.5em;
    }
    .card h2 {
        font-size: 1.3em;
    }
    .messages-box {
        height: 250px;
    }
    .app-header h1 {
        font-size: 1.2em;
    }
    .app-header p {
        display: none; /* Hide tagline on very small screens */
    }
}