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

:root {
    --bg-primary: #1a1a2e;
    --bg-secondary: #16213e;
    --bg-tertiary: #0f3460;
    --bg-input: #1e2757;
    --text-primary: #e4e6eb;
    --text-secondary: #b0b3b8;
    --accent: #e94560;
    --accent-hover: #ff6b6b;
    --user-msg-bg: #1e3a5f;
    --ai-msg-bg: #2d2d44;
    --border-color: #2a2a4a;
    --shadow: 0 2px 10px rgba(0, 0, 0, 0.3);
    --sidebar-width: 280px;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    height: 100vh;
    overflow: hidden;
}

.app-container {
    display: flex;
    height: 100vh;
}

/* Sidebar */
.sidebar {
    width: var(--sidebar-width);
    background: var(--bg-secondary);
    border-right: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    transition: transform 0.3s ease;
}

.sidebar-header {
    padding: 20px;
    border-bottom: 1px solid var(--border-color);
}

.sidebar-header h1 {
    font-size: 1.5rem;
    margin-bottom: 15px;
    color: var(--accent);
}

.btn-new-chat {
    width: 100%;
    padding: 12px 16px;
    background: var(--accent);
    color: white;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    font-size: 0.95rem;
    font-weight: 500;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    transition: background 0.2s;
}

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

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

.chat-item {
    padding: 12px 16px;
    margin-bottom: 5px;
    border-radius: 8px;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: background 0.2s;
}

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

.chat-item.active {
    background: var(--bg-tertiary);
    border-left: 3px solid var(--accent);
}

.chat-item-title {
    flex: 1;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
    font-size: 0.9rem;
}

.chat-item-delete {
    opacity: 0;
    background: none;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    padding: 4px 8px;
    border-radius: 4px;
    transition: all 0.2s;
}

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

.chat-item-delete:hover {
    color: var(--accent);
    background: rgba(233, 69, 96, 0.1);
}

.sidebar.streaming {
    pointer-events: none;
    opacity: 0.6;
}

.sidebar-footer {
    padding: 15px 20px;
    border-top: 1px solid var(--border-color);
}

.btn-clear-all {
    width: 100%;
    padding: 10px;
    background: transparent;
    color: var(--text-secondary);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    cursor: pointer;
    font-size: 0.9rem;
    transition: all 0.2s;
}

.btn-clear-all:hover {
    color: var(--accent);
    border-color: var(--accent);
}

/* Main Chat Area */
.chat-main {
    flex: 1;
    display: flex;
    flex-direction: column;
    min-width: 0;
}

.chat-header {
    padding: 15px 20px;
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    gap: 15px;
}

.btn-toggle-sidebar {
    background: none;
    border: none;
    color: var(--text-primary);
    cursor: pointer;
    padding: 8px;
    border-radius: 6px;
    transition: background 0.2s;
    display: none;
}

.btn-toggle-sidebar:hover {
    background: var(--bg-tertiary);
}

.header-controls {
    display: flex;
    align-items: center;
    gap: 20px;
    flex: 1;
}

.model-selector,
.api-config {
    display: flex;
    align-items: center;
    gap: 8px;
}

.model-selector label,
.api-config label {
    font-size: 0.85rem;
    color: var(--text-secondary);
    white-space: nowrap;
}

.model-selector select {
    padding: 8px 12px;
    background: var(--bg-input);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    font-size: 0.9rem;
    cursor: pointer;
    min-width: 150px;
}

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

.api-config input {
    padding: 8px 12px;
    background: var(--bg-input);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    font-size: 0.9rem;
    width: 200px;
}

.system-prompt-config {
    display: flex;
    align-items: center;
    gap: 8px;
}

.system-prompt-config label {
    font-size: 0.85rem;
    color: var(--text-secondary);
    white-space: nowrap;
}

.system-prompt-config input {
    padding: 8px 12px;
    background: var(--bg-input);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
    border-radius: 6px;
    font-size: 0.9rem;
    width: 250px;
}

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

/* Chat Messages */
.chat-messages {
    flex: 1;
    overflow-y: auto;
    padding: 20px;
    display: flex;
    flex-direction: column;
    gap: 15px;
}

.welcome-screen {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
}

.welcome-content {
    text-align: center;
}

.welcome-icon {
    font-size: 4rem;
    margin-bottom: 20px;
}

.welcome-content h2 {
    font-size: 2rem;
    margin-bottom: 10px;
    color: var(--text-primary);
}

.welcome-content p {
    color: var(--text-secondary);
    font-size: 1.1rem;
}

.message {
    display: flex;
    gap: 12px;
    max-width: 85%;
    animation: fadeIn 0.3s ease;
}

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

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

.message.assistant {
    align-self: flex-start;
}

.message-avatar {
    width: 36px;
    height: 36px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
    flex-shrink: 0;
}

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

.message.assistant .message-avatar {
    background: var(--bg-tertiary);
}

.message-content {
    flex: 1;
    padding: 12px 16px;
    border-radius: 12px;
    line-height: 1.6;
    word-wrap: break-word;
}

.message.user .message-content {
    background: var(--user-msg-bg);
    border-top-right-radius: 4px;
}

.message.assistant .message-content {
    background: var(--ai-msg-bg);
    border-top-left-radius: 4px;
}

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

.message-content p:last-child {
    margin-bottom: 0;
}

/* Thinking Block */
.thinking-block {
    margin-bottom: 12px;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    overflow: hidden;
    background: var(--thinking-bg);
}

.thinking-header {
    padding: 8px 12px;
    background: rgba(233, 69, 96, 0.1);
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 0.85rem;
    color: var(--text-secondary);
    user-select: none;
    transition: background 0.2s;
}

.thinking-header:hover {
    background: rgba(233, 69, 96, 0.15);
}

.thinking-toggle {
    font-size: 0.7rem;
    transition: transform 0.2s;
}

.thinking-toggle.collapsed {
    transform: rotate(-90deg);
}

.thinking-content {
    padding: 12px;
    font-size: 0.85rem;
    color: var(--text-secondary);
    max-height: 300px;
    overflow-y: auto;
    transition: max-height 0.3s ease;
}

.thinking-content.collapsed {
    max-height: 0;
    padding: 0 12px;
    overflow: hidden;
}

/* Chat Input */
.chat-input-area {
    padding: 20px;
    background: var(--bg-secondary);
    border-top: 1px solid var(--border-color);
}

.input-container {
    display: flex;
    align-items: flex-end;
    gap: 10px;
    max-width: 900px;
    margin: 0 auto;
}

#messageInput {
    flex: 1;
    padding: 12px 16px;
    background: var(--bg-input);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    font-size: 1rem;
    font-family: inherit;
    resize: none;
    min-height: 48px;
    max-height: 200px;
    line-height: 1.5;
}

#messageInput:focus {
    outline: none;
    border-color: var(--accent);
}

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

.btn-send {
    padding: 12px 16px;
    background: var(--accent);
    color: white;
    border: none;
    border-radius: 12px;
    cursor: pointer;
    transition: background 0.2s;
    display: flex;
    align-items: center;
    justify-content: center;
}

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

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

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

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

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

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

/* Loading dots */
.loading-dots {
    display: inline-flex;
    gap: 4px;
    padding: 8px 0;
}

.loading-dots span {
    width: 8px;
    height: 8px;
    background: var(--text-secondary);
    border-radius: 50%;
    animation: bounce 1.4s infinite ease-in-out;
}

.loading-dots span:nth-child(1) {
    animation-delay: -0.32s;
}

.loading-dots span:nth-child(2) {
    animation-delay: -0.16s;
}

@keyframes bounce {
    0%, 80%, 100% {
        transform: scale(0);
    }
    40% {
        transform: scale(1);
    }
}

/* Code blocks */
pre {
    background: #0d1117;
    padding: 12px;
    border-radius: 8px;
    overflow-x: auto;
    margin: 8px 0;
}

code {
    font-family: 'Consolas', 'Monaco', 'Courier New', monospace;
    font-size: 0.9em;
}

p code {
    background: rgba(0, 0, 0, 0.3);
    padding: 2px 6px;
    border-radius: 4px;
}

/* Responsive */
@media (max-width: 768px) {
    .sidebar {
        position: fixed;
        left: 0;
        top: 0;
        height: 100vh;
        z-index: 100;
        transform: translateX(-100%);
    }

    .sidebar.open {
        transform: translateX(0);
    }

    .btn-toggle-sidebar {
        display: block;
    }

    .header-controls {
        flex-direction: column;
        gap: 10px;
    }

    .api-config input {
        width: 150px;
    }
}