/* ==================== CSS VARIABLES ==================== */
:root {
    /* Dark Theme (Default) */
    --bg-gradient-start: #1a1a1a;
    --bg-gradient-end: #2d2d2d;
    --text-primary: #ffffff;
    --text-secondary: rgba(255, 255, 255, 0.6);
    --border-primary: rgba(255, 255, 255, 0.2);
    --border-secondary: rgba(255, 255, 255, 0.3);
    --bg-overlay-dark: rgba(0, 0, 0, 0.4);
    --bg-overlay-medium: rgba(0, 0, 0, 0.3);
    --bg-overlay-light: rgba(0, 0, 0, 0.2);
    --bg-glass-light: rgba(255, 255, 255, 0.1);
    --bg-glass-medium: rgba(255, 255, 255, 0.2);
    --bg-glass-strong: rgba(255, 255, 255, 0.3);
    --user-message-bg: rgba(0, 0, 0, 0.6);
    --user-message-text: #ffffff;
    --bot-message-bg: rgba(255, 255, 255, 0.9);
    --bot-message-text: #1a1a1a;
    --input-bg: rgba(255, 255, 255, 0.1);
    --input-border: rgba(255, 255, 255, 0.3);
    --input-text: #ffffff;
    --input-placeholder: rgba(255, 255, 255, 0.6);
    --button-bg: rgba(255, 255, 255, 0.9);
    --button-text: #000000;
    --button-hover-bg: rgba(255, 255, 255, 1);
    --scrollbar-track: rgba(0, 0, 0, 0.2);
    --scrollbar-thumb: rgba(255, 255, 255, 0.5);
    --scrollbar-thumb-hover: rgba(255, 255, 255, 0.7);
}

/* Light Theme */
body.light-theme {
    --bg-gradient-start: #f5f5f5;
    --bg-gradient-end: #e0e0e0;
    --text-primary: #1a1a1a;
    --text-secondary: rgba(0, 0, 0, 0.6);
    --border-primary: rgba(0, 0, 0, 0.2);
    --border-secondary: rgba(0, 0, 0, 0.3);
    --bg-overlay-dark: rgba(255, 255, 255, 0.6);
    --bg-overlay-medium: rgba(255, 255, 255, 0.5);
    --bg-overlay-light: rgba(255, 255, 255, 0.3);
    --bg-glass-light: rgba(0, 0, 0, 0.05);
    --bg-glass-medium: rgba(0, 0, 0, 0.1);
    --bg-glass-strong: rgba(0, 0, 0, 0.15);
    --user-message-bg: rgba(59, 130, 246, 0.9);
    --user-message-text: #ffffff;
    --bot-message-bg: rgba(255, 255, 255, 0.95);
    --bot-message-text: #1a1a1a;
    --input-bg: rgba(255, 255, 255, 0.9);
    --input-border: rgba(0, 0, 0, 0.3);
    --input-text: #1a1a1a;
    --input-placeholder: rgba(0, 0, 0, 0.5);
    --button-bg: rgba(59, 130, 246, 0.9);
    --button-text: #ffffff;
    --button-hover-bg: rgba(59, 130, 246, 1);
    --scrollbar-track: rgba(0, 0, 0, 0.1);
    --scrollbar-thumb: rgba(0, 0, 0, 0.3);
    --scrollbar-thumb-hover: rgba(0, 0, 0, 0.5);
}

/* ==================== BASE STYLES ==================== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    -webkit-tap-highlight-color: transparent;
}

html {
    scroll-behavior: smooth;
    -webkit-text-size-adjust: 100%;
    text-size-adjust: 100%;
    touch-action: manipulation;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, var(--bg-gradient-start) 0%, var(--bg-gradient-end) 100%);
    height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 20px;
    margin: 0;
    overflow: hidden;
    transition: background 0.3s ease;
}

/* ==================== LAYOUT ==================== */
.app-container {
    width: 100%;
    max-width: 1400px;
    height: 90vh;
    display: flex;
    gap: 0;
}

/* ==================== SIDEBAR ==================== */
.sidebar {
    width: 280px;
    background: var(--bg-overlay-dark);
    -webkit-backdrop-filter: blur(10px);
    backdrop-filter: blur(10px);
    border-radius: 20px 0 0 20px;
    border: 1px solid var(--border-primary);
    border-right: none;
    display: flex;
    flex-direction: column;
    overflow: hidden;
    transition: all 0.3s;
}

.sidebar.collapsed {
    width: 0;
    border: none;
    padding: 0;
}

.sidebar-header {
    padding: 20px;
    background: var(--bg-overlay-medium);
    border-bottom: 1px solid var(--border-primary);
}

.new-chat-btn {
    width: 100%;
    padding: 12px;
    background: var(--button-bg);
    color: var(--button-text);
    border: none;
    border-radius: 12px;
    font-size: 15px;
    font-weight: bold;
    cursor: pointer;
    transition: all 0.2s;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
}

.new-chat-btn:hover {
    background: var(--button-hover-bg);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px var(--bg-glass-medium);
}

.chat-list {
    flex: 1;
    overflow-y: auto;
    padding: 10px;
}

.chat-item {
    padding: 12px 15px;
    margin-bottom: 8px;
    background: var(--bg-glass-light);
    border-radius: 10px;
    cursor: pointer;
    transition: all 0.2s;
    border: 1px solid var(--bg-glass-light);
}

.chat-item:hover {
    background: var(--bg-glass-medium);
    transform: translateX(5px);
}

.chat-item.active {
    background: var(--bg-glass-strong);
    border-color: var(--border-secondary);
}

.chat-item-title {
    color: var(--text-primary);
    font-size: 14px;
    font-weight: 500;
    margin-bottom: 4px;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.chat-item-date {
    color: var(--text-secondary);
    font-size: 11px;
}

.chat-item-pin {
    float: left;
    background: rgba(255, 193, 7, 0.3);
    border: none;
    color: #ffc107;
    padding: 2px 8px;
    border-radius: 5px;
    font-size: 12px;
    cursor: pointer;
    opacity: 0;
    transition: all 0.2s;
    margin-right: 5px;
}

.chat-item:hover .chat-item-pin {
    opacity: 1;
}

.chat-item-pin:hover {
    background: rgba(255, 193, 7, 0.6);
}

.chat-item.pinned .chat-item-pin {
    opacity: 1;
    background: rgba(255, 193, 7, 0.5);
}

.chat-item.pinned {
    border-left: 3px solid #ffc107;
    background: rgba(255, 193, 7, 0.1);
}

.chat-item-delete {
    float: right;
    background: rgba(220, 53, 69, 0.5);
    border: none;
    color: white;
    padding: 2px 8px;
    border-radius: 5px;
    font-size: 12px;
    cursor: pointer;
    opacity: 0;
    transition: all 0.2s;
}

.chat-item:hover .chat-item-delete {
    opacity: 1;
}

.chat-item-delete:hover {
    background: rgba(220, 53, 69, 0.8);
}

.sidebar-footer {
    padding: 15px;
    background: var(--bg-overlay-medium);
    border-top: 1px solid var(--border-primary);
}

.clear-all-btn {
    width: 100%;
    padding: 10px;
    background: rgba(220, 53, 69, 0.6);
    color: white;
    border: 1px solid rgba(220, 53, 69, 0.8);
    border-radius: 10px;
    font-size: 13px;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s;
}

.clear-all-btn:hover {
    background: rgba(220, 53, 69, 0.8);
    transform: translateY(-2px);
}

.sidebar-toggle {
    position: absolute;
    left: 280px;
    top: 50%;
    transform: translateY(-50%);
    background: var(--bg-overlay-dark);
    border: 1px solid var(--border-secondary);
    color: var(--text-primary);
    padding: 15px 8px;
    border-radius: 0 10px 10px 0;
    cursor: pointer;
    transition: all 0.3s;
    z-index: 1000;
    font-size: 18px;
}

.sidebar-toggle:hover {
    background: var(--bg-overlay-medium);
    padding-right: 12px;
}

.sidebar.collapsed + .sidebar-toggle {
    left: 0;
}

.chat-list::-webkit-scrollbar {
    width: 6px;
}

.chat-list::-webkit-scrollbar-track {
    background: var(--scrollbar-track);
}

.chat-list::-webkit-scrollbar-thumb {
    background: var(--scrollbar-thumb);
    border-radius: 3px;
}

/* ==================== CHAT CONTAINER ==================== */
.chat-container {
    flex: 1;
    background: var(--bg-glass-light);
    -webkit-backdrop-filter: blur(10px);
    backdrop-filter: blur(10px);
    border-radius: 0 20px 20px 0;
    border: 1px solid var(--border-primary);
    border-left: none;
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

.sidebar.collapsed + .sidebar-toggle + .chat-container {
    border-radius: 20px;
    border-left: 1px solid var(--border-primary);
}

.chat-header {
    background: var(--bg-overlay-medium);
    -webkit-backdrop-filter: blur(10px);
    backdrop-filter: blur(10px);
    color: var(--text-primary);
    padding: 20px;
    text-align: center;
    font-size: 24px;
    font-weight: bold;
    border-bottom: 1px solid var(--border-primary);
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 10px;
}

.header-left-controls,
.header-right-controls {
    display: flex;
    gap: 8px;
    align-items: center;
}

.header-title {
    flex: 1;
    text-align: center;
}

.header-btn {
    background: var(--bg-glass-medium);
    border: 1px solid var(--border-secondary);
    color: var(--text-primary);
    padding: 8px 16px;
    border-radius: 20px;
    cursor: pointer;
    font-size: 14px;
    transition: all 0.3s;
    white-space: nowrap;
}

.header-btn:hover {
    background: var(--bg-glass-strong);
    transform: scale(1.05);
}

.header-btn.danger:hover {
    background: rgba(220, 53, 69, 0.6);
    border-color: rgba(220, 53, 69, 0.8);
}

.theme-toggle {
    background: var(--bg-glass-medium);
    border: 1px solid var(--border-secondary);
    color: var(--text-primary);
    padding: 8px 16px;
    border-radius: 20px;
    cursor: pointer;
    font-size: 14px;
    transition: all 0.3s;
}

.theme-toggle:hover {
    background: var(--bg-glass-strong);
    transform: scale(1.05);
}

/* ==================== CHAT MESSAGES ==================== */
.chat-messages {
    flex: 1;
    padding: 20px;
    overflow-y: auto;
    background: var(--bg-overlay-light);
}

.message {
    margin-bottom: 15px;
    display: flex;
    animation: fadeIn 0.3s ease-in;
    flex-direction: column;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.message.user {
    align-items: flex-end;
}

.message.bot {
    align-items: flex-start;
}

.message-content {
    max-width: 70%;
    padding: 12px 18px;
    border-radius: 18px;
    word-wrap: break-word;
    line-height: 1.4;
    display: flex;
    flex-direction: column;
    white-space: pre-wrap; /* Preserve line breaks and spaces */
}

.message.user .message-content {
    background: var(--user-message-bg);
    -webkit-backdrop-filter: blur(10px);
    backdrop-filter: blur(10px);
    color: var(--user-message-text);
    border: 1px solid var(--border-secondary);
    border-bottom-right-radius: 4px;
}

.message.bot .message-content {
    background: var(--bot-message-bg);
    -webkit-backdrop-filter: blur(10px);
    backdrop-filter: blur(10px);
    color: var(--bot-message-text);
    border: 1px solid var(--border-primary);
    border-bottom-left-radius: 4px;
}

/* Formatting styles */
.message-content h2 {
    font-size: 18px;
    font-weight: 700;
    margin: 12px 0 8px 0;
    color: var(--bot-message-text);
    border-bottom: 2px solid var(--bot-message-text);
    padding-bottom: 4px;
}

.message-content h3 {
    font-size: 16px;
    font-weight: 600;
    margin: 10px 0 6px 0;
    color: var(--bot-message-text);
}

.message-content strong {
    font-weight: 700;
    color: var(--bot-message-text);
}

.message-content em {
    font-style: italic;
}

.message-content u {
    text-decoration: underline;
    text-decoration-thickness: 2px;
}

.message-content ul {
    margin: 10px 0;
    padding-left: 20px;
}

.message-content li {
    margin: 5px 0;
    line-height: 1.6;
}

.message-content p {
    margin: 8px 0;
}

/* ==================== CHAT INPUT ==================== */
.chat-input-container {
    padding: 20px;
    background: var(--bg-overlay-medium);
    -webkit-backdrop-filter: blur(10px);
    backdrop-filter: blur(10px);
    display: flex;
    gap: 10px;
    align-items: flex-end;
    flex-wrap: nowrap;
}

#userInput {
    flex: 1;
    padding: 12px 18px;
    border: 2px solid var(--input-border);
    background: var(--input-bg);
    -webkit-backdrop-filter: blur(10px);
    backdrop-filter: blur(10px);
    color: var(--input-text);
    border-radius: 25px;
    font-size: 16px;
    outline: none;
    transition: border-color 0.3s, background 0.3s, height 0.1s ease;
    resize: none;
    overflow-y: hidden;
    min-height: 44px;
    max-height: 250px; /* 10 lines max on desktop */
    line-height: 1.5;
    font-family: inherit;
    word-wrap: break-word;
    vertical-align: top;
}

#userInput::placeholder {
    color: var(--input-placeholder);
}

#userInput:focus {
    border-color: var(--border-secondary);
    background: var(--bg-glass-medium);
}

/* Custom scrollbar for textarea when content exceeds max-height */
#userInput::-webkit-scrollbar {
    width: 6px;
}

#userInput::-webkit-scrollbar-track {
    background: transparent;
}

#userInput::-webkit-scrollbar-thumb {
    background: var(--scrollbar-thumb);
    border-radius: 3px;
}

#userInput::-webkit-scrollbar-thumb:hover {
    background: var(--scrollbar-thumb-hover);
}

#sendBtn {
    padding: 12px 30px;
    background: var(--button-bg);
    -webkit-backdrop-filter: blur(10px);
    backdrop-filter: blur(10px);
    color: var(--button-text);
    border: 1px solid var(--border-secondary);
    border-radius: 25px;
    font-size: 16px;
    font-weight: bold;
    cursor: pointer;
    transition: all 0.2s;
}

#sendBtn:hover {
    transform: translateY(-2px);
    background: var(--button-hover-bg);
    box-shadow: 0 5px 15px var(--bg-glass-medium);
}

#sendBtn:active {
    transform: translateY(0);
}

#sendBtn:disabled {
    background: rgba(128, 128, 128, 0.5);
    color: rgba(255, 255, 255, 0.5);
    cursor: not-allowed;
    transform: none;
}

.voice-btn {
    padding: 12px 18px;
    background: var(--bg-glass-medium);
    -webkit-backdrop-filter: blur(10px);
    backdrop-filter: blur(10px);
    color: var(--text-primary);
    border: 2px solid var(--border-secondary);
    border-radius: 25px;
    font-size: 20px;
    cursor: pointer;
    transition: all 0.2s;
    display: flex;
    align-items: center;
    justify-content: center;
    min-width: 48px;
}

.voice-btn:hover {
    transform: translateY(-2px);
    background: var(--bg-glass-strong);
    box-shadow: 0 5px 15px var(--bg-glass-medium);
}

.voice-btn:active {
    transform: translateY(0);
}

.voice-btn.listening {
    background: rgba(220, 53, 69, 0.7);
    border-color: rgba(220, 53, 69, 0.9);
    animation: pulse 1.5s infinite;
}

.voice-btn:disabled {
    background: rgba(128, 128, 128, 0.3);
    color: rgba(128, 128, 128, 0.6);
    cursor: not-allowed;
    transform: none;
    opacity: 0.5;
}

@keyframes pulse {
    0%, 100% {
        transform: scale(1);
        box-shadow: 0 0 0 0 rgba(220, 53, 69, 0.7);
    }
    50% {
        transform: scale(1.05);
        box-shadow: 0 0 0 10px rgba(220, 53, 69, 0);
    }
}

/* ==================== LOADING INDICATOR ==================== */
.loading {
    display: none;
    text-align: center;
    padding: 10px;
    color: var(--text-primary);
    font-style: italic;
}

.loading.active {
    display: block;
}

.typing-indicator {
    display: inline-block;
}

.typing-indicator span {
    display: inline-block;
    width: 8px;
    height: 8px;
    background: var(--text-primary);
    border-radius: 50%;
    margin: 0 2px;
    animation: typing 1.4s infinite;
}

.typing-indicator span:nth-child(2) {
    animation-delay: 0.2s;
}

.typing-indicator span:nth-child(3) {
    animation-delay: 0.4s;
}

@keyframes typing {
    0%, 60%, 100% {
        transform: translateY(0);
        opacity: 0.7;
    }
    30% {
        transform: translateY(-10px);
        opacity: 1;
    }
}

/* ==================== SUGGESTIONS ==================== */
.suggestions {
    margin-top: 10px;
    padding: 10px;
    background: var(--bg-glass-light);
    border-radius: 10px;
    font-size: 14px;
}

.suggestion-item {
    display: inline-block;
    margin: 5px;
    padding: 5px 10px;
    background: var(--bg-glass-medium);
    border-radius: 15px;
    cursor: pointer;
    transition: all 0.2s;
}

.suggestion-item:hover {
    background: var(--bg-glass-strong);
    transform: scale(1.05);
}

.confidence-low {
    opacity: 0.85;
    font-style: italic;
}

.confidence-indicator {
    font-size: 12px;
    color: var(--text-secondary);
    margin-top: 5px;
}

/* ==================== TRIPLE QUOTE BLOCKS ==================== */
.triple-quote-block {
    margin: 12px 0;
    border: 2px solid rgba(59, 130, 246, 0.5);
    border-radius: 10px;
    background: rgba(59, 130, 246, 0.05);
    padding: 16px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

body.light-theme .triple-quote-block {
    border: 2px solid rgba(59, 130, 246, 0.6);
    background: rgba(59, 130, 246, 0.08);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.05);
}

.triple-quote-content {
    color: var(--text-primary);
    line-height: 1.6;
    white-space: pre-wrap;
    word-wrap: break-word;
    font-size: 15px;
}

/* ==================== CODE BLOCKS ==================== */
.code-block-wrapper {
    margin: 12px 0;
    border-radius: 8px;
    overflow: hidden;
    background: rgba(0, 0, 0, 0.8);
    border: 1px solid rgba(255, 255, 255, 0.1);
}

body.light-theme .code-block-wrapper {
    background: rgba(245, 245, 245, 0.95);
    border: 1px solid rgba(0, 0, 0, 0.1);
}

.code-block-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 8px 12px;
    background: rgba(0, 0, 0, 0.4);
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

body.light-theme .code-block-header {
    background: rgba(0, 0, 0, 0.05);
    border-bottom: 1px solid rgba(0, 0, 0, 0.1);
}

.code-language {
    font-size: 12px;
    font-weight: 600;
    color: rgba(255, 255, 255, 0.7);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

body.light-theme .code-language {
    color: rgba(0, 0, 0, 0.6);
}

.code-copy-btn {
    background: rgba(59, 130, 246, 0.6);
    color: white;
    border: none;
    padding: 4px 12px;
    border-radius: 5px;
    font-size: 12px;
    cursor: pointer;
    transition: all 0.2s;
    font-weight: 500;
}

.code-copy-btn:hover {
    background: rgba(59, 130, 246, 0.8);
    transform: scale(1.05);
}

.code-copy-btn:active {
    transform: scale(0.95);
}

.code-block {
    margin: 0;
    padding: 12px;
    overflow-x: auto;
    background: transparent;
    font-family: 'Consolas', 'Monaco', 'Courier New', monospace;
    font-size: 14px;
    line-height: 1.6;
    max-height: 500px;
    overflow-y: auto;
}

.code-block code {
    display: block;
    color: #e6e6e6;
    white-space: pre;
    word-wrap: normal;
    word-break: normal;
}

body.light-theme .code-block code {
    color: #333333;
}

/* Scrollbar for code blocks */
.code-block::-webkit-scrollbar {
    width: 8px;
    height: 8px;
}

.code-block::-webkit-scrollbar-track {
    background: rgba(0, 0, 0, 0.2);
}

.code-block::-webkit-scrollbar-thumb {
    background: rgba(255, 255, 255, 0.3);
    border-radius: 4px;
}

.code-block::-webkit-scrollbar-thumb:hover {
    background: rgba(255, 255, 255, 0.5);
}

body.light-theme .code-block::-webkit-scrollbar-track {
    background: rgba(0, 0, 0, 0.05);
}

body.light-theme .code-block::-webkit-scrollbar-thumb {
    background: rgba(0, 0, 0, 0.2);
}

body.light-theme .code-block::-webkit-scrollbar-thumb:hover {
    background: rgba(0, 0, 0, 0.4);
}

/* Mobile optimization for code blocks */
@media screen and (max-width: 768px) {
    .code-block {
        font-size: 12px;
        padding: 10px;
        max-height: 300px;
    }
    
    .code-block-header {
        padding: 6px 10px;
    }
    
    .code-copy-btn {
        padding: 3px 10px;
        font-size: 11px;
    }
}

/* ==================== MESSAGE ACTIONS ==================== */
.message-actions {
    display: flex;
    gap: 8px;
    margin-top: 10px;
    justify-content: flex-start;
    align-items: center;
    width: 100%;
    padding-top: 8px;
    border-top: 1px solid var(--border-primary);
}

.action-btn {
    background: transparent;
    border: 1px solid var(--border-secondary);
    border-radius: 6px;
    padding: 6px 10px;
    cursor: pointer;
    pointer-events: auto;
    transition: all 0.2s;
    font-size: 15px;
    opacity: 0.6;
    user-select: none;
    -webkit-user-select: none;
    color: var(--bot-message-text);
}

.action-btn:hover {
    opacity: 1;
    border-color: var(--border-secondary);
    transform: scale(1.05);
    cursor: pointer;
    text-decoration: none;
}

.action-btn:active {
    transform: scale(0.95);
}

.action-btn.active {
    opacity: 1;
    border-color: var(--border-secondary);
    background: var(--bg-glass-light);
}

.action-btn.dislike-active {
    opacity: 1;
    border-color: var(--border-secondary);
    background: var(--bg-glass-light);
}

/* ==================== SCROLLBARS ==================== */
.chat-messages::-webkit-scrollbar {
    width: 8px;
}

.chat-messages::-webkit-scrollbar-track {
    background: var(--scrollbar-track);
}

.chat-messages::-webkit-scrollbar-thumb {
    background: var(--scrollbar-thumb);
    border-radius: 4px;
}

.chat-messages::-webkit-scrollbar-thumb:hover {
    background: var(--scrollbar-thumb-hover);
}

/* ==================== BROWSER WARNING ==================== */
.browser-warning {
    position: fixed;
    bottom: 20px;
    right: 20px;
    background: rgba(255, 193, 7, 0.95);
    color: #000;
    padding: 12px 20px;
    border-radius: 10px;
    font-size: 13px;
    z-index: 10000;
    box-shadow: 0 4px 12px rgba(0,0,0,0.3);
    display: none;
    max-width: 300px;
    animation: slideIn 0.3s ease;
}

.browser-warning.show {
    display: block;
}

.browser-warning-close {
    background: none;
    border: none;
    font-size: 18px;
    cursor: pointer;
    float: right;
    margin-left: 10px;
    padding: 0;
    line-height: 1;
}

@keyframes slideIn {
    from {
        transform: translateX(400px);
        opacity: 0;
    }
    to {
        transform: translateX(0);
        opacity: 1;
    }
}

/* ==================== MOBILE OVERLAY ==================== */
.sidebar-overlay {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.5);
    z-index: 999;
    opacity: 0;
    transition: opacity 0.3s;
}

.sidebar-overlay.show {
    display: block;
    opacity: 1;
}

/* Mobile menu button */
.mobile-menu-btn {
    display: none;
    position: fixed;
    top: 20px;
    left: 20px;
    background: rgba(0, 0, 0, 0.8);
    border: 1px solid var(--border-secondary);
    color: var(--text-primary);
    padding: 12px 16px;
    border-radius: 10px;
    cursor: pointer;
    z-index: 1001;
    font-size: 18px;
    -webkit-backdrop-filter: blur(10px);
    backdrop-filter: blur(10px);
}

/* ==================== RESPONSIVE DESIGN ==================== */

/* Tablet (landscape and portrait) */
@media screen and (max-width: 1024px) {
    .app-container {
        max-width: 100%;
    }

    .sidebar {
        width: 260px;
    }

    .chat-header {
        font-size: 20px;
        padding: 15px;
    }

    .header-btn, .theme-toggle {
        padding: 6px 12px;
        font-size: 13px;
    }
}

/* Mobile (portrait) */
@media screen and (max-width: 768px) {
    body {
        padding: 0;
    }

    .app-container {
        height: 100vh;
        max-width: 100%;
    }

    .sidebar {
        position: fixed;
        left: -280px;
        top: 0;
        bottom: 0;
        width: 280px;
        z-index: 1000;
        border-radius: 0;
        border: none;
        border-right: 1px solid var(--border-primary);
        transition: left 0.3s ease;
    }

    .sidebar.mobile-open {
        left: 0;
    }

    .sidebar-toggle {
        display: none;
    }

    .mobile-menu-btn {
        display: block;
    }

    .chat-container {
        border-radius: 0;
        border: none;
        width: 100%;
    }

    .chat-header {
        padding: 15px 10px;
        font-size: 18px;
    }

    .header-title {
        font-size: 18px;
    }

    .header-btn, .theme-toggle {
        padding: 6px 10px;
        font-size: 12px;
        white-space: nowrap;
    }

    .header-left-controls,
    .header-right-controls {
        gap: 5px;
    }

    .chat-messages {
        padding: 15px 10px;
    }

    .message-content {
        max-width: 85%;
        font-size: 15px;
        padding: 10px 14px;
    }

    .chat-input-container {
        padding: 10px;
        gap: 8px;
    }

    #userInput {
        font-size: 16px;
        padding: 10px 15px;
        max-height: 200px; /* Limit to ~8 lines on tablet */
    }

    #sendBtn {
        padding: 10px 20px;
        font-size: 15px;
    }

    .voice-btn {
        padding: 10px 14px;
        font-size: 18px;
        min-width: 44px;
    }

    .message-actions {
        flex-wrap: wrap;
    }

    .action-btn {
        padding: 6px 10px;
        font-size: 16px;
    }

    .suggestions {
        flex-direction: column;
    }

    .suggestion-item {
        width: 100%;
    }
}

/* Small mobile (portrait) */
@media screen and (max-width: 480px) {
    .mobile-menu-btn {
        top: 10px;
        left: 10px;
        padding: 10px 14px;
        font-size: 16px;
    }

    .chat-header {
        padding: 12px 8px;
        font-size: 16px;
        gap: 5px;
    }

    .header-title {
        font-size: 16px;
    }

    .header-btn {
        padding: 5px 8px;
        font-size: 11px;
    }

    .theme-toggle {
        padding: 5px 8px;
        font-size: 11px;
    }

    .message-content {
        max-width: 90%;
        font-size: 14px;
    }

    .chat-input-container {
        padding: 8px;
    }

    #userInput {
        font-size: 16px;
        padding: 10px 12px;
        max-height: 150px; /* Limit to ~6 lines on mobile */
        min-height: 44px;
    }

    #sendBtn {
        padding: 10px 16px;
        font-size: 14px;
    }

    .voice-btn {
        padding: 10px 12px;
        font-size: 16px;
        min-width: 44px;
    }

    .sidebar {
        width: 85%;
        max-width: 280px;
        left: -100%;
    }

    .new-chat-btn {
        font-size: 14px;
        padding: 10px;
    }

    .chat-item {
        padding: 10px 12px;
    }

    .chat-item-title {
        font-size: 13px;
    }

    .chat-item-date {
        font-size: 10px;
    }
}

/* Landscape mobile */
@media screen and (max-height: 500px) and (orientation: landscape) {
    .app-container {
        height: 100vh;
    }

    .chat-header {
        padding: 10px;
    }

    .chat-messages {
        padding: 10px;
    }

    .chat-input-container {
        padding: 8px;
    }
}

/* Touch-friendly enhancements */
@media (hover: none) and (pointer: coarse) {
    .header-btn, .theme-toggle, .new-chat-btn, 
    .action-btn, .suggestion-item, .chat-item {
        min-height: 44px;
        min-width: 44px;
    }

    #sendBtn, .voice-btn {
        min-height: 48px;
        min-width: 48px;
    }

    .sidebar {
        -webkit-overflow-scrolling: touch;
    }

    .chat-messages {
        -webkit-overflow-scrolling: touch;
    }

    .chat-list {
        -webkit-overflow-scrolling: touch;
    }
}

/* High DPI screens */
@media (-webkit-min-device-pixel-ratio: 2), (min-resolution: 192dpi) {
    .chat-container,
    .sidebar {
        border-width: 0.5px;
    }
}