:root {
    --bg-primary: #ffffff;
    --bg-secondary: #f7f7f8;
    --bg-tertiary: #f0f0f0;
    --text-primary: #343541;
    --text-secondary: #6e6e80;
    --border-color: #e5e5e5;
    --accent-color: #10a37f;
    --accent-hover: #0e8e6e;
    --user-message-bg: #f7f7f8;
    --ai-message-bg: #ffffff;
    --sidebar-bg: #202123;
    --sidebar-text: #ececf1;
    --sidebar-hover: #2a2b2e;
    --code-bg: #f4f4f4;
    --shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

[data-theme="dark"] {
    --bg-primary: #343541;
    --bg-secondary: #40414f;
    --bg-tertiary: #2c2d38;
    --text-primary: #ececf1;
    --text-secondary: #acacbe;
    --border-color: #4e4f60;
    --user-message-bg: #40414f;
    --ai-message-bg: #444654;
    --sidebar-bg: #202123;
    --sidebar-text: #ececf1;
    --sidebar-hover: #2a2b2e;
    --code-bg: #1e1e1e;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', sans-serif;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    overflow: hidden;
}

/* App Container */
.app-container {
    display: flex;
    height: 100vh;
    overflow: hidden;
}

/* Sidebar */
.sidebar {
    width: 260px;
    background-color: var(--sidebar-bg);
    color: var(--sidebar-text);
    display: flex;
    flex-direction: column;
    transition: transform 0.3s ease;
    z-index: 100;
}

.sidebar.collapsed {
    transform: translateX(-100%);
}

.sidebar-header {
    padding: 1rem;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.new-chat-btn {
    width: 100%;
    padding: 0.75rem;
    background: transparent;
    border: 1px solid rgba(255, 255, 255, 0.2);
    color: var(--sidebar-text);
    border-radius: 8px;
    cursor: pointer;
    font-size: 0.9rem;
    transition: all 0.2s;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
}

.new-chat-btn:hover {
    background-color: var(--sidebar-hover);
    border-color: rgba(255, 255, 255, 0.3);
}

.sidebar-toggle {
    position: absolute;
    top: 1rem;
    right: -40px;
    background: var(--sidebar-bg);
    border: none;
    color: var(--sidebar-text);
    padding: 0.5rem;
    border-radius: 8px;
    cursor: pointer;
    display: none;
}

.sidebar-content {
    flex: 1;
    overflow-y: auto;
    padding: 1rem;
}

.chat-history {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.chat-item {
    padding: 0.75rem;
    border-radius: 8px;
    cursor: pointer;
    transition: background-color 0.2s;
    display: flex;
    align-items: center;
    justify-content: space-between;
    font-size: 0.9rem;
}

.chat-item:hover {
    background-color: var(--sidebar-hover);
}

.chat-item.active {
    background-color: var(--sidebar-hover);
}

.chat-title {
    flex: 1;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.delete-chat {
    background: none;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    padding: 0.25rem;
    border-radius: 4px;
    opacity: 0;
    transition: opacity 0.2s;
}

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

.delete-chat:hover {
    color: #ef4444;
}

.sidebar-footer {
    padding: 1rem;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.user-info {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    margin-bottom: 1rem;
    font-size: 0.9rem;
}

.logout-btn {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    color: var(--sidebar-text);
    text-decoration: none;
    padding: 0.5rem;
    border-radius: 8px;
    transition: background-color 0.2s;
    font-size: 0.9rem;
}

.logout-btn:hover {
    background-color: var(--sidebar-hover);
}

/* Main Content */
.main-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    background-color: var(--bg-primary);
    overflow: hidden;
}

/* Chat Messages Area */
.chat-messages {
    flex: 1;
    overflow-y: auto;
    padding: 2rem 1rem;
}

.messages-container {
    max-width: 800px;
    margin: 0 auto;
}

.message {
    display: flex;
    gap: 1rem;
    padding: 1.5rem;
    animation: fadeIn 0.3s ease;
}

.message.user {
    background-color: var(--user-message-bg);
}

.message.ai {
    background-color: var(--ai-message-bg);
}

.message-avatar {
    width: 32px;
    height: 32px;
    border-radius: 4px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
}

.message.user .message-avatar {
    background-color: var(--accent-color);
    color: white;
}

.message.ai .message-avatar {
    background-color: var(--bg-tertiary);
    color: var(--text-primary);
}

.message-content {
    flex: 1;
    line-height: 1.6;
    overflow-x: auto;
}

.message-content pre {
    background-color: var(--code-bg);
    padding: 1rem;
    border-radius: 8px;
    overflow-x: auto;
    margin: 0.5rem 0;
}

.message-content code {
    background-color: var(--code-bg);
    padding: 0.2rem 0.4rem;
    border-radius: 4px;
    font-family: 'Courier New', monospace;
    font-size: 0.9rem;
}

.message-content p {
    margin-bottom: 0.5rem;
}

.message-content ul, .message-content ol {
    margin: 0.5rem 0;
    padding-left: 1.5rem;
}

.copy-btn {
    background: none;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    padding: 0.25rem;
    border-radius: 4px;
    font-size: 0.8rem;
    float: right;
    margin-left: 0.5rem;
}

.copy-btn:hover {
    color: var(--accent-color);
}

/* Typing Indicator */
.typing-indicator {
    display: flex;
    gap: 0.5rem;
    padding: 1rem;
    background-color: var(--ai-message-bg);
    border-radius: 8px;
    width: fit-content;
}

.typing-indicator span {
    width: 8px;
    height: 8px;
    background-color: var(--text-secondary);
    border-radius: 50%;
    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: 0.5;
    }
    30% {
        transform: translateY(-10px);
        opacity: 1;
    }
}

/* Input Area */
.chat-input-area {
    padding: 1rem;
    border-top: 1px solid var(--border-color);
    background-color: var(--bg-primary);
}

.input-container {
    max-width: 800px;
    margin: 0 auto;
    position: relative;
}

.chat-input {
    width: 100%;
    padding: 1rem;
    padding-right: 3rem;
    border: 1px solid var(--border-color);
    border-radius: 12px;
    background-color: var(--bg-secondary);
    color: var(--text-primary);
    font-size: 1rem;
    resize: none;
    font-family: inherit;
}

.chat-input:focus {
    outline: none;
    border-color: var(--accent-color);
}

.send-btn {
    position: absolute;
    right: 0.75rem;
    bottom: 0.75rem;
    background: var(--accent-color);
    border: none;
    color: white;
    padding: 0.5rem;
    border-radius: 8px;
    cursor: pointer;
    transition: background-color 0.2s;
}

.send-btn:hover {
    background-color: var(--accent-hover);
}

.send-btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

/* Theme Toggle */
.theme-toggle {
    position: fixed;
    bottom: 1rem;
    right: 1rem;
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    color: var(--text-primary);
    padding: 0.75rem;
    border-radius: 50%;
    cursor: pointer;
    z-index: 1000;
    transition: all 0.2s;
}

.theme-toggle:hover {
    transform: scale(1.1);
}

/* Auth Pages */
.auth-page {
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 100vh;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
}

.auth-container {
    width: 100%;
    max-width: 400px;
    padding: 1rem;
}

.auth-card {
    background: white;
    border-radius: 16px;
    padding: 2rem;
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.1);
}

.auth-card h1 {
    font-size: 1.75rem;
    margin-bottom: 0.5rem;
    color: #333;
}

.auth-card p {
    color: #666;
    margin-bottom: 1.5rem;
}

.auth-form .form-group {
    margin-bottom: 1rem;
}

.auth-form label {
    display: block;
    margin-bottom: 0.5rem;
    color: #333;
    font-weight: 500;
}

.auth-form input {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid #ddd;
    border-radius: 8px;
    font-size: 1rem;
    transition: border-color 0.2s;
}

.auth-form input:focus {
    outline: none;
    border-color: #667eea;
}

.btn {
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    cursor: pointer;
    transition: all 0.2s;
}

.btn-primary {
    background: #667eea;
    color: white;
}

.btn-primary:hover {
    background: #5a67d8;
    transform: translateY(-1px);
}

.btn-block {
    width: 100%;
}

.alert {
    padding: 0.75rem;
    border-radius: 8px;
    margin-bottom: 1rem;
}

.alert-error {
    background-color: #fee;
    color: #c33;
    border: 1px solid #fcc;
}

.alert-success {
    background-color: #efe;
    color: #3c3;
    border: 1px solid #cfc;
}

.auth-link {
    text-align: center;
    margin-top: 1.5rem;
    color: #666;
}

.auth-link a {
    color: #667eea;
    text-decoration: none;
}

.auth-link a:hover {
    text-decoration: underline;
}

/* Loading States */
.loading-history {
    text-align: center;
    padding: 2rem;
    color: var(--text-secondary);
}

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

/* Responsive Design */
@media (max-width: 768px) {
    .sidebar {
        position: fixed;
        top: 0;
        left: 0;
        height: 100%;
        transform: translateX(-100%);
    }
    
    .sidebar.open {
        transform: translateX(0);
    }
    
    .sidebar-toggle {
        display: block;
    }
    
    .message {
        padding: 1rem;
    }
    
    .chat-messages {
        padding: 1rem;
    }
    
    .auth-card {
        padding: 1.5rem;
    }
}

/* Scrollbar */
::-webkit-scrollbar {
    width: 8px;
    height: 8px;
}

::-webkit-scrollbar-track {
    background: var(--bg-secondary);
}

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

::-webkit-scrollbar-thumb:hover {
    background: var(--text-secondary);
}