/* ============================================================
   STEM Copilot — Stylesheet
   Montserrat, dark theme, premium chat UI
   ============================================================ */

:root {
    --brand-orange: #EB5A28;
    --brand-orange-hover: #cf4f22;
    --brand-orange-glow: rgba(235, 90, 40, 0.25);
    --bg-main: #000000;
    --bg-sidebar: #0a0a0a;
    --bg-input: #1a1a1a;
    --bg-hover: #1f1f1f;
    --bg-card: #141414;
    --bg-elevated: #1c1c1c;
    --text-primary: #ececec;
    --text-secondary: #888888;
    --text-muted: #555555;
    --border-color: #262626;
    --border-subtle: #1e1e1e;
    --msg-user: #2a2a2a;
    --msg-ai: transparent;
    --radius: 12px;
    --radius-lg: 16px;
    --radius-xl: 24px;
    --transition: 0.25s cubic-bezier(0.4, 0, 0.2, 1);
    --sidebar-width: 280px;
    --rail-width: 56px;
}

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

html {
    -webkit-text-size-adjust: 100%;
    -ms-text-size-adjust: 100%;
    touch-action: manipulation;
    overscroll-behavior: none;
}

body {
    font-family: 'Montserrat', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    background-color: var(--bg-main);
    color: var(--text-primary);
    height: 100vh;
    height: 100dvh;
    overflow: hidden;
    touch-action: manipulation;
    -webkit-tap-highlight-color: transparent;
    overscroll-behavior: none;
}


/* ============================================================
   LOGIN SCREEN
   ============================================================ */

.login-screen {
    position: fixed;
    inset: 0;
    z-index: 1000;
    background: var(--bg-main);
    display: flex;
    align-items: center;
    justify-content: center;
}

.login-card {
    text-align: center;
    max-width: 400px;
    padding: 48px 36px;
}

.login-logo {
    width: 100px;
    height: 100px;
    margin-bottom: 28px;
    border-radius: 50%;
    object-fit: cover;
}

.login-logo-stembotix {
    height: 48px;
    margin-bottom: 32px;
    object-fit: contain;
}

.login-title {
    font-size: 24px;
    font-weight: 700;
    margin-bottom: 8px;
    color: var(--text-primary);
    white-space: nowrap;
}

.login-subtitle {
    font-size: 14px;
    color: var(--text-secondary);
    margin-bottom: 32px;
    line-height: 1.6;
}

.google-btn-wrap {
    display: flex;
    justify-content: center;
    margin-bottom: 20px;
}

.gsi-custom-btn {
    display: inline-flex;
    align-items: center;
    gap: 12px;
    background: #1a1a1a;
    border: 1px solid #333;
    border-radius: 24px;
    padding: 12px 28px;
    color: #f0ece6;
    font-family: 'Montserrat', sans-serif;
    font-size: 13px;
    font-weight: 700;
    cursor: pointer;
    transition: background 0.2s, border-color 0.2s, transform 0.1s;
    white-space: nowrap;
}

.gsi-custom-btn:hover {
    background: #222;
    border-color: #555;
}

.gsi-custom-btn:active {
    transform: scale(0.97);
}

.login-footer {
    font-size: 11px;
    color: var(--text-muted);
    margin-top: 16px;
}


/* ============================================================
   BYOK ONBOARDING
   ============================================================ */

.byok-screen {
    position: fixed;
    inset: 0;
    z-index: 999;
    background: var(--bg-main);
    display: flex;
    align-items: center;
    justify-content: center;
}

.byok-card {
    text-align: center;
    max-width: 440px;
    padding: 48px 36px;
}

.byok-card h2 { font-size: 22px; font-weight: 700; margin-bottom: 12px; }

.byok-desc { font-size: 14px; color: var(--text-secondary); line-height: 1.6; margin-bottom: 20px; }

.byok-steps {
    text-align: left;
    padding-left: 20px;
    margin-bottom: 24px;
    font-size: 14px;
    line-height: 2;
    color: var(--text-secondary);
}

.byok-steps a { color: var(--brand-orange); text-decoration: none; }
.byok-steps a:hover { text-decoration: underline; }

.byok-submit-btn {
    width: 100%;
    padding: 14px;
    margin-top: 16px;
    background: var(--brand-orange);
    color: #fff;
    border: none;
    border-radius: var(--radius);
    font-family: inherit;
    font-size: 15px;
    font-weight: 600;
    cursor: pointer;
    transition: background var(--transition);
}

.byok-submit-btn:hover { background: var(--brand-orange-hover); }
.byok-note { font-size: 11px; color: var(--text-muted); margin-top: 12px; }


/* ============================================================
   PWA INSTALL BANNER
   ============================================================ */

.install-banner {
    position: fixed;
    bottom: calc(24px + env(safe-area-inset-bottom));
    left: 50%;
    transform: translateX(-50%);
    z-index: 1000;
    background: var(--bg-elevated);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 12px 16px;
    display: flex;
    align-items: center;
    gap: 12px;
    box-shadow: 0 12px 48px rgba(0,0,0,0.8);
    max-width: 400px;
    width: calc(100% - 32px);
    animation: slideUp 0.4s cubic-bezier(0.16, 1, 0.3, 1);
}

.install-banner-icon { width: 36px; height: 36px; border-radius: 8px; }

.install-banner-text {
    flex: 1;
    display: flex;
    flex-direction: column;
    font-size: 13px;
    line-height: 1.4;
}

.install-banner-text strong { color: var(--text-primary); }
.install-banner-text span { color: var(--text-secondary); font-size: 11px; }

.install-banner-btn {
    background: var(--brand-orange);
    color: #fff;
    border: none;
    border-radius: 8px;
    padding: 8px 16px;
    font-family: inherit;
    font-size: 13px;
    font-weight: 600;
    cursor: pointer;
    transition: background var(--transition);
}

.install-banner-btn:hover { background: var(--brand-orange-hover); }

.install-banner-dismiss {
    background: none;
    border: none;
    color: var(--text-muted);
    font-size: 18px;
    cursor: pointer;
    padding: 0 4px;
}

@keyframes slideUp {
    from { opacity: 0; transform: translateX(-50%) translateY(20px); }
    to   { opacity: 1; transform: translateX(-50%) translateY(0); }
}


/* ============================================================
   APP CONTAINER
   ============================================================ */

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


/* ============================================================
   SIDEBAR (full) — premium look
   ============================================================ */

.sidebar {
    width: var(--sidebar-width);
    flex-shrink: 0;
    background: var(--bg-sidebar);
    display: flex;
    flex-direction: column;
    border-right: 1px solid var(--border-color);
    transition: margin-left var(--transition), opacity var(--transition);
    position: relative;
    z-index: 20;
}

.sidebar.collapsed {
    margin-left: calc(-1 * var(--sidebar-width));
    opacity: 0;
    pointer-events: none;
}

.sidebar-top {
    flex: 1;
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

.sidebar-logo-row {
    padding: 18px 18px 8px;
    display: flex;
    align-items: center;
}

.sidebar-logo {
    height: 30px;
    object-fit: contain;
}

.new-chat-btn {
    margin: 8px 14px;
    padding: 12px 16px;
    background: linear-gradient(135deg, rgba(235,90,40,0.08), rgba(235,90,40,0.02));
    border: 1px solid rgba(235,90,40,0.2);
    color: var(--text-primary);
    border-radius: var(--radius);
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 14px;
    font-weight: 600;
    font-family: inherit;
    transition: background var(--transition), border-color var(--transition), box-shadow var(--transition);
}

.new-chat-btn:hover {
    background: linear-gradient(135deg, rgba(235,90,40,0.15), rgba(235,90,40,0.05));
    border-color: rgba(235,90,40,0.4);
    box-shadow: 0 0 16px rgba(235,90,40,0.1);
}

.new-chat-btn svg {
    color: var(--brand-orange);
}

.chat-history {
    flex: 1;
    overflow-y: auto;
    padding: 6px 10px;
    display: flex;
    flex-direction: column;
    gap: 3px;
}

.history-item {
    position: relative;
    padding: 10px 12px;
    border-radius: 10px;
    cursor: pointer;
    color: var(--text-secondary);
    font-size: 13px;
    display: flex;
    align-items: center;
    gap: 10px;
    transition: background var(--transition), color var(--transition), transform 0.15s;
}

.history-item:hover {
    background: var(--bg-hover);
    color: var(--text-primary);
}

.history-item:active {
    transform: scale(0.98);
}

.history-item.active {
    background: linear-gradient(135deg, rgba(235,90,40,0.1), rgba(235,90,40,0.03));
    color: var(--text-primary);
    border: 1px solid rgba(235,90,40,0.15);
}

.history-item:not(.active) {
    border: 1px solid transparent;
}

.thread-icon {
    flex-shrink: 0;
    opacity: 0.4;
    width: 16px;
    height: 16px;
}

.history-item.active .thread-icon {
    opacity: 0.8;
    color: var(--brand-orange);
}

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

.options-btn {
    background: none; border: none;
    color: var(--text-secondary);
    font-size: 18px; line-height: 1;
    cursor: pointer; opacity: 0;
    padding: 0 4px;
    flex-shrink: 0;
    transition: opacity 0.2s, color 0.2s;
}

.history-item:hover .options-btn,
.options-btn.menu-open { opacity: 1; }
.options-btn:hover { color: var(--text-primary); }

.options-menu {
    position: absolute;
    right: 10px; top: 40px;
    background: var(--bg-elevated);
    border: 1px solid var(--border-color);
    border-radius: 10px;
    display: none;
    flex-direction: column;
    z-index: 100;
    box-shadow: 0 8px 32px rgba(0,0,0,0.7);
    min-width: 130px;
    overflow: hidden;
}

.options-menu.show { display: flex; }

.option-item {
    padding: 10px 14px;
    font-size: 13px;
    color: var(--text-primary);
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 8px;
    transition: background 0.2s;
}

.option-item:hover { background: var(--bg-hover); }
.option-item.delete { color: #ff4a4a; }

.rename-input {
    width: 100%;
    background: transparent; border: none;
    color: var(--text-primary);
    font-family: inherit; font-size: 13px;
    outline: none;
    border-bottom: 1px solid var(--brand-orange);
    padding: 2px 0;
}


/* --- Sidebar bottom — user profile (premium look) --- */

.sidebar-bottom {
    padding: 12px 14px 16px;
    border-top: 1px solid var(--border-color);
    position: relative;
    background: linear-gradient(180deg, transparent, rgba(235,90,40,0.02));
}

.user-profile-btn {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 10px 12px;
    border-radius: 12px;
    cursor: pointer;
    transition: background var(--transition), box-shadow var(--transition);
    border: 1px solid transparent;
}

.user-profile-btn:hover {
    background: var(--bg-hover);
    border-color: var(--border-color);
    box-shadow: 0 2px 12px rgba(0,0,0,0.3);
}

.user-avatar {
    width: 34px; height: 34px;
    border-radius: 50%;
    object-fit: cover;
    background: var(--bg-hover);
    border: 2px solid var(--border-color);
    transition: border-color var(--transition);
}

.user-profile-btn:hover .user-avatar {
    border-color: var(--brand-orange);
}

.user-name {
    flex: 1;
    font-size: 13px;
    font-weight: 600;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.user-menu-arrow { opacity: 0.5; transition: transform 0.2s; }

.user-menu {
    display: none;
    position: absolute;
    bottom: 72px; left: 14px; right: 14px;
    background: var(--bg-elevated);
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    box-shadow: 0 8px 32px rgba(0,0,0,0.7);
    overflow: hidden;
    z-index: 50;
}

.user-menu.show { display: block; }

.user-menu-item {
    padding: 12px 16px;
    font-size: 13px;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 10px;
    transition: background 0.2s;
}

.user-menu-item:hover { background: var(--bg-hover); }
.user-menu-logout { color: #ff4a4a; }


/* ============================================================
   SIDEBAR RAIL (collapsed mode — desktop only)
   ============================================================ */

.sidebar-rail {
    width: var(--rail-width);
    flex-shrink: 0;
    background: var(--bg-sidebar);
    border-right: 1px solid var(--border-color);
    display: none;
    flex-direction: column;
    justify-content: space-between;
    align-items: center;
    padding: 12px 0;
    z-index: 20;
}

.sidebar-rail.visible {
    display: flex;
}

.rail-top, .rail-bottom {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 4px;
}

.rail-icon-btn {
    width: 40px; height: 40px;
    border-radius: 10px;
    background: transparent;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: background var(--transition), color var(--transition);
}

.rail-icon-btn:hover {
    background: var(--bg-hover);
    color: var(--text-primary);
}

.rail-logo {
    width: 34px; height: 34px;
    border-radius: 6px;
    object-fit: contain;
}

.rail-avatar {
    width: 28px; height: 28px;
    border-radius: 50%;
    object-fit: cover;
    background: var(--bg-hover);
}


/* ============================================================
   MAIN CHAT AREA
   ============================================================ */

.main-chat {
    flex: 1;
    display: flex;
    flex-direction: column;
    position: relative;
    min-width: 0;
}

.main-header {
    position: absolute;
    top: 0; left: 0;
    width: 100%;
    padding: 14px 20px;
    display: flex;
    align-items: center;
    z-index: 10;
}

.toggle-sidebar-btn {
    background: transparent; border: none;
    color: var(--text-secondary);
    cursor: pointer;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 8px;
    border-radius: 8px;
    transition: background 0.2s, color 0.2s;
}

.toggle-sidebar-btn:hover {
    background: var(--bg-hover);
    color: var(--text-primary);
}

.chat-container {
    flex: 1;
    overflow-y: auto;
    padding: 64px 20px 20px;
    display: flex;
    flex-direction: column;
    gap: 24px;
    scroll-behavior: smooth;
}


/* ============================================================
   HERO / WELCOME SCREEN
   ============================================================ */

.hero-welcome {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    flex: 1;
    gap: 24px;
    user-select: none;
    padding: 40px 20px;
}

.hero-bot-icon {
    width: 120px;
    height: 120px;
    object-fit: contain;
    animation: heroFloat 3s ease-in-out infinite;
    filter: drop-shadow(0 8px 24px rgba(235, 90, 40, 0.15));
}

@keyframes heroFloat {
    0%, 100% { transform: translateY(0); }
    50%      { transform: translateY(-8px); }
}

.hero-title {
    font-size: 32px;
    font-weight: 700;
    color: var(--text-primary);
    text-align: center;
    line-height: 1.3;
}

.hero-input-wrap {
    width: 100%;
    max-width: 640px;
}

.hero-input-box {
    display: flex;
    align-items: flex-end;
    background: var(--bg-input);
    border: 1.5px solid var(--border-color);
    border-radius: var(--radius-xl);
    transition: border-color 0.3s, box-shadow 0.3s;
    box-shadow: 0 2px 12px rgba(0,0,0,0.3);
}

.hero-input-box:focus-within {
    border-color: var(--brand-orange);
    box-shadow: 0 0 0 3px var(--brand-orange-glow), 0 4px 20px rgba(0,0,0,0.4);
}

.hero-input-box textarea {
    flex: 1;
    background: transparent; border: none;
    color: var(--text-primary);
    padding: 16px 12px;
    font-family: inherit;
    font-size: 15px;
    resize: none; outline: none;
    height: 54px; max-height: 120px;
    line-height: 1.5;
    overflow-y: hidden;
}

.hero-input-box textarea::placeholder { color: var(--text-muted); }

.hero-pills {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 10px;
    max-width: 560px;
    width: 100%;
}

.hero-pill {
    padding: 14px 16px;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    color: var(--text-secondary);
    font-family: inherit;
    font-size: 13px;
    font-weight: 500;
    cursor: pointer;
    text-align: left;
    transition: background var(--transition), color var(--transition), border-color var(--transition), box-shadow var(--transition);
}

.hero-pill:hover {
    background: var(--bg-hover);
    border-color: var(--brand-orange);
    color: var(--text-primary);
    box-shadow: 0 0 0 1px var(--brand-orange-glow);
}


/* ============================================================
   MESSAGES
   ============================================================ */

.message-row {
    display: flex;
    width: 100%;
    max-width: 800px;
    margin: 0 auto;
    animation: fadeIn 0.35s ease-out forwards;
}

.message-row.user { justify-content: flex-end; }
.message-row.ai   { justify-content: flex-start; }

.message-content {
    padding: 14px 18px;
    border-radius: var(--radius);
    font-size: 14px;
    line-height: 1.6;
    color: var(--text-primary);
    overflow-wrap: break-word;
}

.user .message-content {
    max-width: 75%;
    background: var(--msg-user);
    border-bottom-right-radius: 4px;
    color: var(--text-primary);
}

.ai .message-content {
    max-width: 100%;
    background: var(--msg-ai);
}

.ai-avatar {
    width: 30px; height: 30px;
    border-radius: 50%;
    background-image: url('/assets/bot.png');
    background-size: cover;
    background-position: center;
    margin-right: 14px;
    flex-shrink: 0;
    margin-top: 4px;
}

.ai-avatar.pulsing {
    animation: avatarPulse 1.5s ease-in-out infinite;
}

@keyframes avatarPulse {
    0%, 100% { opacity: 0.6; transform: scale(1); }
    50%      { opacity: 1;   transform: scale(1.05); }
}


/* --- Thinking indicator --- */

.thinking-indicator {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 8px 0;
    animation: fadeIn 0.3s ease-out;
}

.thinking-indicator.hidden { display: none; }

.thinking-logo {
    width: 22px; height: 22px;
    border-radius: 50%;
    animation: pulse 1.5s ease-in-out infinite;
}

.thinking-text {
    font-size: 13px;
    color: var(--text-secondary);
    font-style: italic;
}

@keyframes pulse {
    0%, 100% { opacity: 0.5; transform: scale(1); }
    50%      { opacity: 1;   transform: scale(1.08); }
}


/* --- Rendered markdown in AI messages --- */

.message-content h1, .message-content h2, .message-content h3 {
    margin-top: 16px; margin-bottom: 8px;
    font-weight: 600;
}
.message-content h1 { font-size: 1.25em; }
.message-content h2 { font-size: 1.12em; }
.message-content h3 { font-size: 1.05em; }
.message-content p { margin-bottom: 10px; }

.message-content ul, .message-content ol { margin: 8px 0 8px 20px; }
.message-content li { margin-bottom: 4px; }

.message-content code {
    background: #1e1e1e;
    padding: 2px 6px;
    border-radius: 4px;
    font-family: 'Courier New', monospace;
    font-size: 0.88em;
}

.message-content pre {
    background: #111;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 14px;
    overflow-x: auto;
    margin: 10px 0;
}

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

.message-content table { border-collapse: collapse; margin: 10px 0; width: 100%; }
.message-content th, .message-content td {
    border: 1px solid var(--border-color);
    padding: 8px 12px;
    text-align: left;
    font-size: 14px;
}
.message-content th { background: var(--bg-input); font-weight: 600; }

.message-content blockquote {
    border-left: 3px solid var(--brand-orange);
    padding-left: 12px;
    margin: 10px 0;
    color: var(--text-secondary);
}

.katex { color: var(--text-primary); }
.katex-display { margin: 14px 0; overflow-x: auto; }

.message-image {
    max-width: 240px;
    border-radius: 8px;
    margin-bottom: 8px;
}


/* ============================================================
   INPUT AREA (bottom bar during chat)
   ============================================================ */

.input-container {
    padding: 16px 20px 10px;
    background: linear-gradient(180deg, transparent, var(--bg-main) 20%);
    display: flex;
    flex-direction: column;
    align-items: center;
    z-index: 10;
}

.image-preview-bar {
    max-width: 800px;
    width: 100%;
    display: flex;
    align-items: center;
    gap: 8px;
    margin-bottom: 8px;
    padding: 6px 10px;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
}

.image-preview-thumb {
    width: 48px; height: 48px;
    border-radius: 6px;
    background-size: cover;
    background-position: center;
}

.image-preview-remove {
    margin-left: auto;
    background: none; border: none;
    color: var(--text-secondary);
    font-size: 20px;
    cursor: pointer;
    padding: 4px 8px;
    transition: color 0.2s;
}

.image-preview-remove:hover { color: #ff4a4a; }

.input-box {
    width: 100%; max-width: 800px;
    position: relative;
    display: flex;
    align-items: flex-end;
    background: var(--bg-input);
    border: 1.5px solid var(--border-color);
    border-radius: var(--radius-xl);
    transition: border-color 0.3s, box-shadow 0.3s;
    box-shadow: 0 2px 12px rgba(0,0,0,0.3);
}

.input-box:focus-within {
    border-color: var(--brand-orange);
    box-shadow: 0 0 0 3px var(--brand-orange-glow), 0 4px 20px rgba(0,0,0,0.4);
}

.upload-btn {
    background: none; border: none;
    color: var(--text-secondary);
    cursor: pointer;
    padding: 16px 4px 16px 16px;
    display: flex;
    align-items: center;
    transition: color 0.2s;
}

.upload-btn:hover { color: var(--text-primary); }

#userInput {
    flex: 1;
    background: transparent; border: none;
    color: var(--text-primary);
    padding: 16px 12px 16px 16px;
    font-family: inherit;
    font-size: 14px;
    resize: none; outline: none;
    height: 54px; max-height: 200px;
    line-height: 1.5;
    overflow-y: hidden;
}

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

.send-btn {
    background: none; border: none;
    color: var(--text-secondary);
    cursor: pointer;
    padding: 16px 16px 16px 4px;
    display: flex;
    align-items: center;
    transition: color 0.2s, transform 0.1s;
}

.send-btn:hover { color: var(--brand-orange); }
.send-btn:active { transform: scale(0.92); }
.send-btn svg { width: 20px; height: 20px; fill: currentColor; }

.stop-btn {
    background: none; border: none;
    color: var(--brand-orange);
    cursor: pointer;
    padding: 16px 16px 16px 4px;
    display: none;
    align-items: center;
    transition: color 0.2s, transform 0.1s;
}

.stop-btn.visible { display: flex; }

.stop-btn:hover { color: #ff4a4a; }
.stop-btn:active { transform: scale(0.92); }
.stop-btn svg { width: 22px; height: 22px; fill: currentColor; }

.disclaimer-text {
    font-size: 11px;
    color: rgba(255,255,255,0.5);
    font-weight: 500;
    margin-top: 10px;
    text-align: center;
}


/* ============================================================
   SETTINGS MODAL
   ============================================================ */

.modal-overlay {
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(0,0,0,0.6);
    z-index: 500;
    align-items: center;
    justify-content: center;
}

.modal-overlay.show { display: flex; }

.settings-modal {
    background: var(--bg-sidebar);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    width: 600px;
    max-width: 92vw;
    height: 520px;
    max-height: 88vh;
    overflow: hidden;
    box-shadow: 0 8px 40px rgba(0,0,0,0.6);
    display: flex;
    flex-direction: column;
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px 24px;
    border-bottom: 1px solid var(--border-color);
    flex-shrink: 0;
}

.modal-header h2 { font-size: 18px; font-weight: 600; }

.modal-close {
    background: none; border: none;
    color: var(--text-secondary);
    font-size: 24px;
    cursor: pointer;
    padding: 0 4px;
    transition: color 0.2s;
}

.modal-close:hover { color: var(--text-primary); }

.modal-body {
    padding: 0;
    overflow: hidden;
}

.settings-layout {
    display: flex;
    flex: 1;
    overflow: hidden;
}

.settings-nav {
    width: 160px;
    flex-shrink: 0;
    background: var(--bg-main);
    padding: 16px 8px;
    display: flex;
    flex-direction: column;
    gap: 2px;
    border-right: 1px solid var(--border-color);
}

.settings-nav-btn {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 10px 12px;
    background: none;
    border: none;
    color: var(--text-secondary);
    font-family: inherit;
    font-size: 13px;
    font-weight: 500;
    cursor: pointer;
    border-radius: 8px;
    transition: background var(--transition), color var(--transition);
    text-align: left;
    width: 100%;
}

.settings-nav-btn:hover { background: var(--bg-hover); color: var(--text-primary); }
.settings-nav-btn.active { background: var(--bg-hover); color: var(--text-primary); font-weight: 600; }

.settings-panel {
    flex: 1;
    padding: 24px;
    overflow-y: auto;
    min-width: 0;
}

.tab-content { display: none; }
.tab-content.active { display: block; }

.settings-section-title {
    font-size: 14px;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 10px;
}

.settings-input, .settings-textarea {
    width: 100%;
    padding: 11px 14px;
    background: var(--bg-input);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    color: var(--text-primary);
    font-family: inherit;
    font-size: 14px;
    outline: none;
    transition: border-color 0.2s;
}

.settings-input:focus, .settings-textarea:focus { border-color: var(--brand-orange); }
.settings-input::placeholder, .settings-textarea::placeholder { color: var(--text-muted); }

.settings-textarea {
    resize: vertical;
    min-height: 80px;
    line-height: 1.5;
}

.settings-select {
    width: 100%;
    padding: 11px 14px;
    background: var(--bg-input);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    color: var(--text-primary);
    font-family: inherit;
    font-size: 14px;
    outline: none;
    cursor: pointer;
    appearance: none;
    -webkit-appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' fill='%23888' viewBox='0 0 16 16'%3E%3Cpath d='M8 11L3 6h10z'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 12px center;
    transition: border-color 0.2s;
}

.settings-select:focus { border-color: var(--brand-orange); }
.settings-select option { background: var(--bg-input); color: var(--text-primary); }

.settings-save-btn {
    margin-top: 12px;
    padding: 10px 24px;
    background: var(--brand-orange);
    color: #fff;
    border: none;
    border-radius: 8px;
    font-family: inherit;
    font-size: 13px;
    font-weight: 600;
    cursor: pointer;
    transition: background var(--transition);
}

.settings-save-btn:hover { background: var(--brand-orange-hover); }

.settings-hint {
    font-size: 12px;
    color: var(--text-muted);
    margin-top: 8px;
    line-height: 1.5;
}

.settings-hint a { color: var(--brand-orange); text-decoration: none; }
.settings-hint a:hover { text-decoration: underline; }

.persona-option {
    display: flex;
    flex-direction: column;
    gap: 4px;
    padding: 14px 16px;
    border-radius: var(--radius);
    border: 1px solid var(--border-color);
    cursor: pointer;
    margin-bottom: 8px;
    transition: border-color 0.2s, background 0.2s;
}

.persona-option:hover { background: var(--bg-hover); }
.persona-option.active { border-color: var(--brand-orange); background: rgba(235,90,40,0.06); }

.persona-name { font-size: 14px; font-weight: 600; color: var(--text-primary); }
.persona-desc { font-size: 12px; color: var(--text-secondary); line-height: 1.5; }


/* ============================================================
   ANIMATIONS & SCROLLBAR
   ============================================================ */

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(8px); }
    to   { opacity: 1; transform: translateY(0); }
}

::-webkit-scrollbar { width: 5px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: #333; border-radius: 4px; }
::-webkit-scrollbar-thumb:hover { background: #555; }

.cursor::after {
    content: '\25CB';
    animation: blink 1s step-start infinite;
    color: var(--brand-orange);
    margin-left: 2px;
}

@keyframes blink { 50% { opacity: 0; } }


/* ============================================================
   ERROR MESSAGE
   ============================================================ */

.error-message {
    color: #ff6b6b;
    font-style: italic;
    padding: 10px 14px;
    background: rgba(255,75,75,0.08);
    border-radius: 8px;
    border-left: 3px solid #ff4a4a;
}


/* ============================================================
   RESPONSIVE — MOBILE
   ============================================================ */

.mobile-fab-toggle { display: none !important; }

/* Sidebar overlay — mobile only (hidden on desktop) */
.sidebar-overlay {
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(0,0,0,0.55);
    z-index: 35;
    -webkit-tap-highlight-color: transparent;
}
.sidebar-overlay.visible { display: block; }

@media (max-width: 768px) {
    /* App container */
    .app-container {
        overflow: hidden;
        position: relative;
    }

    /* Sidebar — fixed overlay on mobile */
    .sidebar {
        position: fixed; left: 0; top: 0;
        width: var(--sidebar-width);
        height: 100vh;
        height: 100dvh;
        z-index: 40;
        transition: transform var(--transition), opacity var(--transition);
        margin-left: 0 !important;
    }

    .sidebar.collapsed {
        transform: translateX(calc(-1 * var(--sidebar-width)));
        opacity: 0;
        pointer-events: none;
    }

    .sidebar:not(.collapsed) {
        transform: translateX(0);
        opacity: 1;
        pointer-events: auto;
    }

    .sidebar-rail { display: none !important; }

    /* Main chat fills full screen */
    .main-chat {
        width: 100vw;
        min-width: 0;
        flex: 1;
    }

    /* Sidebar logo bigger on mobile */
    .sidebar-logo {
        height: 36px;
    }

    .sidebar-logo-row {
        padding: 20px 18px 10px;
    }

    /* Settings modal */
    .settings-modal {
        width: 96vw;
        height: 78vh;
        max-height: 78vh;
    }

    .settings-layout {
        flex-direction: row;
        min-height: unset;
    }

    .settings-nav {
        width: 52px;
        min-width: 52px;
        flex-direction: column;
        padding: 10px 4px;
        border-right: 1px solid var(--border-color);
        border-bottom: none;
        overflow-x: unset;
        overflow-y: auto;
        gap: 4px;
        align-items: center;
    }

    .settings-nav-btn {
        width: 40px;
        height: 40px;
        padding: 0;
        justify-content: center;
        border-radius: 10px;
        white-space: normal;
    }
    .settings-nav-btn span,
    .settings-nav-btn > :not(svg) { display: none; }
    .settings-nav-btn svg { width: 18px; height: 18px; flex-shrink: 0; }
    .settings-nav-btn.active {
        background: var(--bg-elevated);
        color: var(--brand-orange);
    }

    .settings-panel { padding: 14px 12px; flex: 1; min-width: 0; }

    .hero-title { font-size: 22px; }
    .hero-bot-icon { width: 80px; height: 80px; }

    /* Hero welcome — scrollable so pills don't go off-screen */
    .hero-welcome {
        justify-content: flex-start;
        padding: 20px 16px calc(20px + env(safe-area-inset-bottom));
        overflow-y: auto;
        min-height: 0;
    }

    .hero-pills { grid-template-columns: 1fr; }
    .hero-pill { font-size: 12px; padding: 12px 14px; }

    .hero-input-wrap { max-width: 100%; }

    .login-title { font-size: 20px; white-space: normal; }

    /* Chat container */
    .chat-container {
        padding: 60px 10px 16px;
        gap: 16px;
        height: 100%;
    }

    .message-row {
        max-width: 100%;
    }

    .ai-avatar {
        display: none;
    }
    .ai .message-content {
        font-size: 13px;
        line-height: 1.55;
        padding: 0 2px;
    }

    .user .message-content {
        max-width: 88%;
        font-size: 13px;
    }

    .thinking-indicator .thinking-logo {
        display: none;
    }

    .input-container {
        padding: 10px 10px calc(6px + env(safe-area-inset-bottom));
    }

    .disclaimer-text {
        font-size: 10px;
        margin-top: 6px;
    }

    /* History items — always show options on mobile (no hover) */
    .history-item .options-btn {
        opacity: 0.6;
    }
}

@media (max-width: 480px) {
    .hero-title { font-size: 20px; }
    .hero-input-box textarea { font-size: 13px; }
    .ai .message-content { font-size: 12.5px; }
    .user .message-content { font-size: 12.5px; }
    .katex-display { overflow-x: auto; font-size: 0.95em; }
    .message-content pre { font-size: 11px; }
}