/* Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --bg-primary: #0f172a;
    --bg-secondary: #1e293b;
    --bg-tertiary: #334155;
    --bg-hover: #475569;
    --text-primary: #f1f5f9;
    --text-secondary: #cbd5e1;
    --text-muted: #94a3b8;
    --border-color: #334155;
    --accent: #3b82f6;
    --accent-hover: #2563eb;
    --user-bg: #1e40af;
    --assistant-bg: #1e293b;
    --success: #10b981;
    --error: #ef4444;
    --shadow: rgba(0, 0, 0, 0.3);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen',
        'Ubuntu', 'Cantarell', 'Fira Sans', 'Droid Sans', 'Helvetica Neue', sans-serif;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
}

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

/* Sidebar */
.sidebar {
    width: 260px;
    background-color: var(--bg-secondary);
    border-right: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
}

.sidebar-header {
    padding: 1rem;
    border-bottom: 1px solid var(--border-color);
}

.new-chat-btn {
    width: 100%;
    padding: 0.75rem 1rem;
    background-color: var(--bg-tertiary);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.875rem;
    font-weight: 500;
    transition: all 0.2s;
}

.new-chat-btn:hover {
    background-color: var(--bg-hover);
}

.conversations-list {
    flex: 1;
    overflow-y: auto;
    padding: 0.5rem;
}

.conversation-item {
    padding: 0.75rem;
    margin-bottom: 0.25rem;
    border-radius: 0.5rem;
    cursor: pointer;
    transition: background-color 0.2s;
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 0.5rem;
}

.conversation-item:hover {
    background-color: var(--bg-tertiary);
}

.conversation-item.active {
    background-color: var(--bg-tertiary);
}

.conversation-title {
    flex: 1;
    font-size: 0.875rem;
    color: var(--text-secondary);
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.conversation-delete {
    background: none;
    border: none;
    color: var(--text-muted);
    cursor: pointer;
    padding: 0.25rem;
    opacity: 0;
    transition: opacity 0.2s;
}

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

.conversation-delete:hover {
    color: var(--error);
}

.sidebar-footer {
    padding: 1rem;
    border-top: 1px solid var(--border-color);
}

.cost-stats {
    font-size: 0.75rem;
    color: var(--text-muted);
}

.stat-item {
    display: flex;
    justify-content: space-between;
    margin-bottom: 0.25rem;
}

.stat-value {
    color: var(--text-secondary);
    font-weight: 600;
}

/* Chat Container */
.chat-container {
    flex: 1;
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

.chat-header {
    padding: 1rem 2rem;
    background-color: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.chat-header h1 {
    font-size: 1.25rem;
    font-weight: 600;
}

.model-selector select {
    padding: 0.5rem 1rem;
    background-color: var(--bg-tertiary);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    cursor: pointer;
    font-size: 0.875rem;
}

.model-selector select:focus {
    outline: none;
    border-color: var(--accent);
}

/* Messages */
.messages-container {
    flex: 1;
    overflow-y: auto;
    padding: 2rem;
    scroll-behavior: smooth;
}

.welcome-message {
    text-align: center;
    padding: 4rem 2rem;
    color: var(--text-muted);
}

.welcome-message h2 {
    margin-bottom: 0.5rem;
    color: var(--text-secondary);
}

.message {
    margin-bottom: 1.5rem;
    display: flex;
    gap: 1rem;
    animation: fadeIn 0.3s ease-in;
}

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

.message-avatar {
    width: 36px;
    height: 36px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
    font-weight: 600;
    font-size: 0.875rem;
}

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

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

.message-content {
    flex: 1;
    max-width: 48rem;
}

.message-role {
    font-size: 0.875rem;
    font-weight: 600;
    margin-bottom: 0.25rem;
    color: var(--text-secondary);
}

.message-text {
    color: var(--text-primary);
    line-height: 1.6;
    word-wrap: break-word;
}

.message-text p {
    margin-bottom: 0.75rem;
}

.message-text code {
    background-color: var(--bg-tertiary);
    padding: 0.125rem 0.25rem;
    border-radius: 0.25rem;
    font-size: 0.875rem;
    font-family: 'Courier New', monospace;
}

.message-text pre {
    background-color: var(--bg-tertiary);
    padding: 1rem;
    border-radius: 0.5rem;
    overflow-x: auto;
    margin-bottom: 0.75rem;
}

.message-text pre code {
    background: none;
    padding: 0;
}

.message-timestamp {
    font-size: 0.75rem;
    color: var(--text-muted);
    margin-top: 0.25rem;
}

.typing-indicator {
    display: flex;
    gap: 0.25rem;
    padding: 0.5rem 0;
}

.typing-dot {
    width: 8px;
    height: 8px;
    background-color: var(--text-muted);
    border-radius: 50%;
    animation: typing 1.4s infinite;
}

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

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

@keyframes typing {
    0%, 60%, 100% {
        opacity: 0.3;
        transform: translateY(0);
    }
    30% {
        opacity: 1;
        transform: translateY(-10px);
    }
}

/* Input Container */
.input-container {
    padding: 1rem 2rem 1.5rem;
    background-color: var(--bg-secondary);
    border-top: 1px solid var(--border-color);
}

.input-wrapper {
    display: flex;
    gap: 0.75rem;
    align-items: flex-end;
    background-color: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    border-radius: 0.75rem;
    padding: 0.75rem;
    transition: border-color 0.2s;
}

.input-wrapper:focus-within {
    border-color: var(--accent);
}

#messageInput {
    flex: 1;
    background: none;
    border: none;
    color: var(--text-primary);
    font-size: 1rem;
    resize: none;
    max-height: 200px;
    outline: none;
    font-family: inherit;
}

#messageInput::placeholder {
    color: var(--text-muted);
}

.send-btn {
    background-color: var(--accent);
    color: white;
    border: none;
    border-radius: 0.5rem;
    width: 36px;
    height: 36px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: background-color 0.2s;
    flex-shrink: 0;
}

.send-btn:hover:not(:disabled) {
    background-color: var(--accent-hover);
}

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

.input-hint {
    font-size: 0.75rem;
    color: var(--text-muted);
    margin-top: 0.5rem;
    text-align: center;
}

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

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

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

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

/* Responsive */
@media (max-width: 768px) {
    .sidebar {
        position: absolute;
        left: -260px;
        height: 100%;
        z-index: 100;
        transition: left 0.3s;
    }

    .sidebar.open {
        left: 0;
    }

    .chat-header h1 {
        font-size: 1rem;
    }

    .messages-container {
        padding: 1rem;
    }

    .input-container {
        padding: 1rem;
    }
}