* {
    box-sizing: border-box;
}

:root {
    --bg: #111214;
    --panel: #17191d;
    --panel-alt: #1d2024;
    --line: rgba(255, 255, 255, 0.08);
    --line-strong: rgba(255, 255, 255, 0.12);
    --text: #f3f4f6;
    --muted: #9ca3af;
    --muted-strong: #d1d5db;
    --accent: #38bdf8;
    --user: #dbeafe;
    --user-text: #0f172a;
    color-scheme: dark;
}

html,
body {
    height: 100%;
}

body {
    margin: 0;
    min-height: 100vh;
    background: var(--bg);
    color: var(--text);
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    font-size: 15px;
    line-height: 1.5;
    -webkit-font-smoothing: antialiased;
    text-rendering: optimizeLegibility;
}

.app {
    min-height: 100vh;
}

.top-header,
.main-content,
.input-container {
    width: min(840px, calc(100% - 32px));
    margin: 0 auto;
}

.top-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
    padding: 18px 0;
    border-bottom: 1px solid var(--line);
}

.brand-link {
    text-decoration: none;
}

.main-logo {
    margin: 0;
    font-size: 1rem;
    font-weight: 700;
    letter-spacing: -0.02em;
    color: var(--text);
}

.header-controls {
    display: flex;
    align-items: center;
    gap: 10px;
}

.header-model-selector {
    position: relative;
}

.model-selector-btn,
.new-chat-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    height: 38px;
    padding: 0 14px;
    border: 1px solid var(--line);
    border-radius: 999px;
    background: transparent;
    color: var(--text);
    font-size: 0.92rem;
    font-weight: 600;
    cursor: pointer;
    transition: border-color 0.2s ease, background 0.2s ease;
}

.model-selector-btn:hover,
.new-chat-btn:hover {
    border-color: var(--line-strong);
    background: rgba(255, 255, 255, 0.03);
}

.model-selector-btn {
    min-width: 190px;
    justify-content: space-between;
}

.model-name {
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.new-chat-label {
    display: inline-block;
}

.model-dropdown {
    position: absolute;
    top: calc(100% + 10px);
    right: 0;
    min-width: 300px;
    padding: 8px;
    border: 1px solid var(--line);
    border-radius: 16px;
    background: var(--panel);
    box-shadow: 0 20px 40px -24px rgba(0, 0, 0, 0.95);
    opacity: 0;
    visibility: hidden;
    transform: translateY(-8px);
    transition: opacity 0.18s ease, transform 0.18s ease, visibility 0.18s ease;
    z-index: 1000;
}

.model-dropdown.show {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.model-option {
    padding: 12px 14px;
    border-radius: 12px;
    cursor: pointer;
    transition: background 0.2s ease;
}

.model-option:hover,
.model-option.active {
    background: rgba(255, 255, 255, 0.04);
}

.model-option-name {
    font-size: 0.95rem;
    font-weight: 600;
    color: var(--text);
}

.model-option-desc {
    margin-top: 4px;
    font-size: 0.84rem;
    color: var(--muted);
    line-height: 1.45;
}

.model-option-divider {
    margin: 8px 0;
    border-top: 1px solid var(--line);
}

.main-content {
    padding: 28px 0 172px;
}

.active-model-bar {
    display: flex;
    align-items: baseline;
    gap: 10px;
    flex-wrap: wrap;
    color: var(--muted);
    font-size: 0.94rem;
    padding-bottom: 18px;
}

.active-model-label {
    font-size: 0.78rem;
    font-weight: 700;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: var(--muted);
}

.active-model-bar strong {
    color: var(--text);
    font-size: 0.98rem;
    letter-spacing: -0.02em;
}

.active-model-description {
    color: var(--muted);
}

.chat-container {
    min-height: 64vh;
}

.messages {
    display: flex;
    flex-direction: column;
    gap: 18px;
    min-height: 420px;
}

.welcome-message {
    max-width: 620px;
    margin: 56px auto 0;
    text-align: left;
}

.welcome-label {
    display: inline-block;
    margin-bottom: 12px;
    color: var(--muted);
    font-size: 0.78rem;
    font-weight: 700;
    letter-spacing: 0.08em;
    text-transform: uppercase;
}

.welcome-message h2 {
    margin: 0;
    font-size: clamp(2rem, 5vw, 2.8rem);
    line-height: 1.08;
    letter-spacing: -0.04em;
}

.welcome-message p {
    margin: 16px 0 0;
    color: var(--muted);
    font-size: 1rem;
    line-height: 1.7;
}

.starter-prompts {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin-top: 28px;
}

.starter-chip {
    padding: 10px 14px;
    border: 1px solid var(--line);
    border-radius: 999px;
    background: transparent;
    color: var(--muted-strong);
    font-size: 0.88rem;
    font-weight: 600;
    cursor: pointer;
    transition: border-color 0.2s ease, background 0.2s ease, color 0.2s ease;
}

.starter-chip:hover {
    border-color: var(--line-strong);
    background: rgba(255, 255, 255, 0.03);
    color: var(--text);
}

.welcome-note {
    margin-top: 18px !important;
    font-size: 0.92rem !important;
}

.message {
    display: flex;
    flex-direction: column;
    gap: 6px;
}

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

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

.message-content {
    max-width: min(720px, 100%);
    padding: 14px 16px;
    border-radius: 18px;
    background: var(--panel);
    border: 1px solid var(--line);
    color: var(--text);
    font-size: 1rem;
    line-height: 1.7;
    word-break: break-word;
}

.message.user .message-content {
    background: var(--user);
    border-color: rgba(255, 255, 255, 0.12);
    color: var(--user-text);
}

.message-time {
    color: var(--muted);
    font-size: 0.72rem;
    padding: 0 4px;
}

.message-content h1,
.message-content h2,
.message-content h3,
.message-content h4,
.message-content h5,
.message-content h6 {
    margin: 0 0 10px;
    color: inherit;
    line-height: 1.25;
}

.message-content h1 { font-size: 1.35em; }
.message-content h2 { font-size: 1.28em; }
.message-content h3 { font-size: 1.18em; }

.message-content p {
    margin: 0 0 12px;
}

.message-content p:last-child,
.message-content ul:last-child,
.message-content ol:last-child,
.message-content pre:last-child,
.message-content blockquote:last-child {
    margin-bottom: 0;
}

.message-content ul,
.message-content ol {
    margin: 0 0 12px;
    padding-left: 20px;
}

.message-content li {
    margin: 4px 0;
}

.message-content blockquote {
    margin: 0 0 12px;
    padding-left: 14px;
    border-left: 2px solid rgba(255, 255, 255, 0.18);
    color: inherit;
    opacity: 0.88;
}

.message-content code {
    padding: 2px 6px;
    border-radius: 8px;
    background: rgba(255, 255, 255, 0.06);
    font-family: ui-monospace, SFMono-Regular, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace;
    font-size: 0.92em;
}

.message.user .message-content code {
    background: rgba(15, 23, 42, 0.08);
}

.message-content pre {
    margin: 0 0 12px;
    padding: 14px 16px;
    border-radius: 14px;
    background: rgba(0, 0, 0, 0.22);
    overflow-x: auto;
}

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

.message-content .math-inline {
    padding: 2px 6px;
    border-radius: 8px;
    background: rgba(255, 255, 255, 0.04);
}

.message-content .math-block {
    margin: 0 0 12px;
    padding: 14px 16px;
    border: 1px solid rgba(255, 255, 255, 0.08);
    border-radius: 14px;
    background: rgba(255, 255, 255, 0.02);
    overflow-x: auto;
    text-align: center;
}

.message-content .math-boxed {
    border-color: rgba(56, 189, 248, 0.35) !important;
}

.message-content a {
    color: var(--accent);
}

.message.user .message-content a {
    color: #1d4ed8;
}

.debate-header {
    margin: 24px 0 16px;
    padding: 16px 20px;
    border-radius: 16px;
    background: rgba(56, 189, 248, 0.08);
    border: 1px solid rgba(56, 189, 248, 0.2);
}

.debate-header h3 {
    margin: 0 0 8px;
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text);
}

.debate-meta {
    margin: 0;
    font-size: 0.85rem;
    color: var(--muted);
}

.debate-evidence {
    margin: 20px 0;
    padding: 16px;
    border-radius: 16px;
    background: rgba(148, 163, 184, 0.08);
    border: 1px solid rgba(148, 163, 184, 0.18);
}

.debate-evidence-item {
    margin-top: 10px;
}

.debate-evidence-item summary {
    cursor: pointer;
    color: var(--text);
    font-weight: 600;
}

.debate-evidence-item pre {
    margin: 10px 0 0;
    white-space: pre-wrap;
    color: var(--muted);
    font-family: inherit;
    font-size: 0.85rem;
    line-height: 1.5;
}

.debate-round {
    margin: 20px 0;
}

.debate-round-label {
    margin-bottom: 12px;
    font-size: 0.85rem;
    font-weight: 700;
    letter-spacing: 0.06em;
    text-transform: uppercase;
    color: var(--muted);
}

.debate-agents-container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
}

.debate-agent {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.debate-agent-label {
    font-size: 0.78rem;
    font-weight: 700;
    letter-spacing: 0.06em;
    text-transform: uppercase;
    color: var(--muted);
}

.debate-agent.agent-a .debate-agent-label {
    color: var(--accent);
}

.debate-agent.agent-b .debate-agent-label {
    color: #a855f7;
}

.debate-agent.agent-a .message-content {
    background: rgba(56, 189, 248, 0.08);
    border-color: rgba(56, 189, 248, 0.25);
}

.debate-agent.agent-b .message-content {
    background: rgba(168, 85, 247, 0.08);
    border-color: rgba(168, 85, 247, 0.25);
}

.debate-agent-error .message-content {
    background: rgba(239, 68, 68, 0.08);
    border-color: rgba(239, 68, 68, 0.25);
}

.debate-synthesis {
    background: rgba(34, 197, 94, 0.08);
    border-color: rgba(34, 197, 94, 0.25);
}

.debate-final-answers {
    margin-top: 28px;
}

.debate-final-answer {
    background: rgba(34, 197, 94, 0.08);
    border-color: rgba(34, 197, 94, 0.25);
}

@media (max-width: 768px) {
    .debate-agents-container {
        grid-template-columns: 1fr;
    }
}

.typing-indicator {
    display: flex;
    align-items: center;
    gap: 5px;
    padding: 2px 0;
}

.typing-dot {
    width: 5px;
    height: 5px;
    border-radius: 50%;
    background: var(--muted);
    animation: typing 1.15s ease-in-out infinite;
}

.typing-dot:nth-child(2) {
    animation-delay: 0.15s;
}

.typing-dot:nth-child(3) {
    animation-delay: 0.3s;
}

.input-area {
    position: fixed;
    left: 0;
    right: 0;
    bottom: 0;
    padding: 18px 0 24px;
    background: linear-gradient(to top, rgba(17, 18, 20, 1), rgba(17, 18, 20, 0.95), rgba(17, 18, 20, 0));
    backdrop-filter: blur(8px);
}

.input-wrapper {
    display: flex;
    align-items: flex-end;
    gap: 12px;
    padding: 14px 16px;
    border: 1px solid var(--line);
    border-radius: 24px;
    background: rgba(255, 255, 255, 0.03);
}

.input-wrapper:focus-within {
    border-color: rgba(56, 189, 248, 0.28);
}

#messageInput {
    flex: 1;
    min-height: 24px;
    max-height: 140px;
    padding: 0;
    border: none;
    outline: none;
    resize: none;
    background: transparent;
    color: var(--text);
    font: inherit;
    line-height: 1.6;
}

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

.send-btn {
    width: 36px;
    height: 36px;
    border: none;
    border-radius: 999px;
    background: var(--text);
    color: #111214;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    flex-shrink: 0;
    transition: opacity 0.2s ease, transform 0.2s ease;
}

.send-btn:disabled {
    opacity: 0.35;
    cursor: not-allowed;
}

.send-btn:not(:disabled):hover {
    opacity: 0.92;
    transform: translateY(-1px);
}

.input-footer {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    padding: 8px 4px 0;
    color: var(--muted);
    font-size: 0.78rem;
}

.input-hint,
.char-count {
    color: var(--muted);
}

::-webkit-scrollbar {
    width: 8px;
    height: 8px;
}

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

::-webkit-scrollbar-thumb {
    background: rgba(255, 255, 255, 0.12);
    border-radius: 999px;
}

::-webkit-scrollbar-thumb:hover {
    background: rgba(255, 255, 255, 0.2);
}

@keyframes typing {
    0%, 60%, 100% {
        opacity: 0.3;
        transform: translateY(0);
    }
    30% {
        opacity: 1;
        transform: translateY(-3px);
    }
}

@media (max-width: 820px) {
    .top-header,
    .main-content,
    .input-container {
        width: min(100% - 24px, 840px);
    }

    .top-header {
        flex-direction: column;
        align-items: flex-start;
    }

    .header-controls {
        width: 100%;
        justify-content: space-between;
    }

    .model-dropdown {
        left: 0;
        right: auto;
    }
}

@media (max-width: 560px) {
    .main-content {
        padding-top: 22px;
    }

    .header-controls {
        flex-wrap: wrap;
    }

    .model-selector-btn {
        width: 100%;
    }

    .new-chat-btn {
        width: 100%;
    }

    .model-dropdown {
        min-width: 100%;
    }

    .active-model-bar {
        flex-direction: column;
        gap: 6px;
    }

    .welcome-message {
        margin-top: 28px;
    }

    .welcome-message h2 {
        font-size: 2rem;
    }

    .starter-prompts {
        flex-direction: column;
    }

    .input-footer {
        flex-direction: column;
        align-items: flex-start;
    }
}