/* =====================================================
   Chat with me · Secure WebRTC Chat
   视觉参考：Enclave（深色加密原生 + 工程师审美）
   主色：#10B981 翡翠绿 / #34D399 浅绿
   背景：#0B0F13 / #0D1117 / #161B22
   ===================================================== */

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700;800&family=JetBrains+Mono:wght@400;500;600&display=swap');

/* ---------- 设计令牌 ---------- */
:root {
  --bg-base: #0B0F13;
  --bg-panel: #0D1117;
  --bg-deep: #080A0D;
  --bg-elev: #161B22;
  --bg-hover: #1F2937;

  --text-primary: #E2E8F0;
  --text-secondary: #94A3B8;
  --text-muted: #64748B;
  --text-inverse: #000;

  --accent: #10B981;
  --accent-bright: #34D399;
  --accent-glow: rgba(16, 185, 129, 0.4);
  --accent-faint: rgba(16, 185, 129, 0.1);
  --accent-border: rgba(16, 185, 129, 0.2);

  --border: #1F2937;
  --border-strong: #30363D;
  --border-mid: #374151;

  --warning: #EAB308;
  --danger: #ef4444;

  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-mono: 'JetBrains Mono', 'SF Mono', Menlo, Monaco, Consolas, monospace;

  --shadow-lg: 0 0 15px rgba(16, 185, 129, 0.4);
  --shadow-md: 0 8px 32px rgba(0, 0, 0, 0.5);
}

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

html, body {
  height: 100%;
  background: var(--bg-base);
  color: var(--text-primary);
  font-family: var(--font-sans);
  font-size: 14px;
  line-height: 1.5;
  overflow: hidden;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

button, input, textarea, select {
  font-family: inherit;
  color: inherit;
}

button { cursor: pointer; border: none; background: none; }

a { color: var(--accent); text-decoration: none; }

/* ---------- 滚动条 ---------- */
::-webkit-scrollbar { width: 8px; height: 8px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 4px; }
::-webkit-scrollbar-thumb:hover { background: var(--border-mid); }

/* =========================================================
   主布局：左 280px 侧栏 + 右 1fr 会话
   ========================================================= */
.app-shell {
  display: grid;
  grid-template-columns: 288px 1fr;
  height: 100vh;
  background: var(--bg-base);
}

/* ---------- 侧栏 ---------- */
.sidebar {
  display: flex;
  flex-direction: column;
  background: var(--bg-deep);
  border-right: 1px solid var(--border);
  overflow: hidden;
}

.sidebar-header {
  height: 64px;
  padding: 0 24px;
  display: flex;
  align-items: center;
  gap: 8px;
  border-bottom: 1px solid var(--border);
  background: var(--bg-panel);
  flex-shrink: 0;
}

.sidebar-brand {
  display: flex;
  align-items: center;
  gap: 8px;
}

.brand-icon {
  width: 28px;
  height: 28px;
  border-radius: 8px;
  background: linear-gradient(135deg, var(--accent) 0%, var(--accent-bright) 100%);
  display: grid;
  place-items: center;
  color: var(--text-inverse);
  font-weight: 800;
  font-size: 14px;
  box-shadow: 0 0 12px var(--accent-faint);
}

.brand-name {
  font-weight: 700;
  letter-spacing: 0.02em;
  color: #fff;
  font-size: 15px;
}

.section-label {
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.15em;
  color: var(--text-muted);
  text-transform: uppercase;
  padding: 20px 24px 8px;
}

.identity-list {
  flex: 1;
  overflow-y: auto;
  padding: 0 12px 16px;
}

.identity-card {
  background: var(--bg-elev);
  border-left: 2px solid var(--accent);
  border-radius: 8px;
  padding: 12px;
  margin-bottom: 12px;
}

.identity-card.peer {
  border-left-color: var(--accent-bright);
  opacity: 0.92;
}

.identity-card.waiting {
  border: 1px solid var(--border-strong);
  background: var(--bg-elev);
  border-left: none;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  gap: 12px;
  padding: 16px;
}

.identity-row {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 12px;
}

.identity-avatar {
  width: 40px;
  height: 40px;
  border-radius: 8px;
  background: var(--bg-panel);
  display: grid;
  place-items: center;
  flex-shrink: 0;
  color: var(--text-secondary);
}

.identity-avatar.peer {
  background: var(--accent-bright);
  color: var(--text-inverse);
}

.identity-info {
  flex: 1;
  overflow: hidden;
}

.identity-name {
  font-size: 13px;
  font-weight: 600;
  color: var(--text-primary);
}

.identity-status {
  font-size: 11px;
  color: var(--accent);
  font-weight: 500;
}

.identity-status.peer { color: var(--accent-bright); }
.identity-status.muted { color: var(--text-muted); }

.fingerprint-block {
  padding-top: 12px;
  border-top: 1px solid var(--border-mid);
}

.fingerprint-label {
  font-size: 9px;
  color: var(--text-muted);
  font-family: var(--font-mono);
  letter-spacing: 0.12em;
  text-transform: uppercase;
  margin-bottom: 4px;
}

.fingerprint-value {
  font-size: 11px;
  color: var(--text-secondary);
  font-family: var(--font-mono);
  word-break: break-all;
  line-height: 1.5;
}

.sidebar-footer {
  padding: 12px 20px;
  border-top: 1px solid var(--border);
  background: var(--bg-deep);
}

.sidebar-footer-tag {
  font-size: 10px;
  font-family: var(--font-mono);
  color: var(--accent);
  opacity: 0.7;
  letter-spacing: 0.08em;
  display: flex;
  align-items: center;
  gap: 6px;
  text-transform: uppercase;
}

.sidebar-footer-tag .dot {
  display: inline-block;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 6px var(--accent);
}

/* =========================================================
   右侧会话面板
   ========================================================= */
.session-panel {
  display: flex;
  flex-direction: column;
  background: var(--bg-base);
  overflow: hidden;
  min-width: 0;
}

.session-topbar {
  height: 64px;
  flex-shrink: 0;
  padding: 0 32px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  border-bottom: 1px solid var(--border);
  background: var(--bg-panel);
}

.session-topbar-info {
  display: flex;
  align-items: center;
  gap: 12px;
  min-width: 0;
}

.session-topbar-title {
  font-size: 14px;
  font-weight: 700;
  color: #fff;
  letter-spacing: 0.02em;
  display: flex;
  align-items: center;
  gap: 8px;
}

.session-topbar-title .sep {
  color: var(--text-muted);
  font-weight: 400;
}

.session-topbar-code {
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--text-secondary);
  letter-spacing: 0.06em;
  margin-left: 6px;
}

.session-topbar-actions {
  display: flex;
  align-items: center;
  gap: 16px;
}

.e2ee-badge {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 10px;
  font-family: var(--font-mono);
  letter-spacing: 0.06em;
  padding: 6px 10px;
  border-radius: 6px;
  border: 1px solid var(--accent-border);
  background: var(--accent-faint);
  color: var(--accent);
  text-transform: uppercase;
}

.e2ee-badge.is-waiting {
  border-color: rgba(234, 179, 8, 0.2);
  background: rgba(234, 179, 8, 0.1);
  color: var(--warning);
}

.e2ee-badge.is-failed {
  border-color: rgba(239, 68, 68, 0.2);
  background: rgba(239, 68, 68, 0.1);
  color: var(--danger);
}

.e2ee-badge svg {
  width: 12px;
  height: 12px;
}

.icon-btn {
  width: 32px;
  height: 32px;
  border-radius: 6px;
  display: grid;
  place-items: center;
  color: var(--text-muted);
  border: 1px solid transparent;
  transition: all 0.15s;
}

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

.icon-btn.is-on {
  background: var(--bg-hover);
  border-color: var(--border-mid);
  color: #fff;
}

.icon-btn svg { width: 16px; height: 16px; }

/* =========================================================
   消息流
   ========================================================= */
.message-stream {
  flex: 1;
  overflow-y: auto;
  padding: 24px 32px 32px;
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.secure-banner {
  align-self: center;
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 10px;
  font-family: var(--font-mono);
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-muted);
  padding: 6px 12px;
  border-radius: 999px;
  background: var(--bg-elev);
  border: 1px solid var(--border-strong);
  margin-bottom: 24px;
}

.secure-banner.is-connected { color: var(--accent); border-color: var(--accent-border); }
.secure-banner.is-connected svg { color: var(--accent); }

.secure-banner svg { width: 12px; height: 12px; }

/* 系统消息 */
.timeline-system {
  align-self: center;
  font-size: 10px;
  font-family: var(--font-mono);
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-muted);
  padding: 4px 12px;
  border-radius: 999px;
  background: var(--bg-elev);
  border: 1px solid var(--border);
}

.timeline-system.success { color: var(--accent); border-color: var(--accent-border); }
.timeline-system.error { color: var(--danger); border-color: rgba(239, 68, 68, 0.3); }

/* 消息气泡 */
.timeline-item {
  display: flex;
  gap: 16px;
  max-width: 672px;
  align-items: flex-end;
}

.timeline-item.outgoing {
  align-self: flex-end;
  flex-direction: row-reverse;
}

.msg-avatar {
  width: 32px;
  height: 32px;
  border-radius: 8px;
  display: grid;
  place-items: center;
  font-size: 11px;
  font-weight: 700;
  flex-shrink: 0;
  font-family: var(--font-mono);
}

.msg-avatar.mine {
  background: var(--border-mid);
  color: #fff;
}

.msg-avatar.peer {
  background: var(--accent-bright);
  color: var(--text-inverse);
}

.msg-body {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.timeline-item.outgoing .msg-body { align-items: flex-end; }
.timeline-item:not(.outgoing) .msg-body { align-items: flex-start; }

.msg-bubble {
  padding: 14px 16px;
  border-radius: 14px;
  font-size: 14px;
  line-height: 1.6;
  word-wrap: break-word;
  overflow-wrap: anywhere;
  white-space: pre-wrap;
  max-width: 480px;
  position: relative;
}

.timeline-item.outgoing .msg-bubble {
  background: var(--accent);
  color: var(--text-inverse);
  border-top-right-radius: 0;
  font-weight: 500;
}

.timeline-item:not(.outgoing) .msg-bubble {
  background: var(--bg-elev);
  color: var(--text-primary);
  border: 1px solid var(--border-strong);
  border-top-left-radius: 0;
}

.msg-meta {
  font-size: 10px;
  font-family: var(--font-mono);
  color: var(--text-muted);
  letter-spacing: 0.08em;
  text-transform: uppercase;
  margin-top: 2px;
  padding: 0 4px;
}

.timeline-item.outgoing .msg-meta { color: var(--accent-bright); }

/* 文件气泡 */
.file-bubble {
  min-width: 260px;
}

.file-row {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 6px;
}

.file-icon { font-size: 16px; }

.file-name {
  font-weight: 600;
  font-size: 13px;
  word-break: break-all;
}

.file-detail {
  font-size: 11px;
  font-family: var(--font-mono);
  color: var(--text-secondary);
  margin-bottom: 8px;
  opacity: 0.85;
}

.file-progress {
  width: 100%;
  height: 4px;
  background: var(--bg-deep);
  border-radius: 2px;
  overflow: hidden;
  margin-bottom: 6px;
}

.file-progress-fill {
  height: 100%;
  background: var(--accent-bright);
  transition: width 0.2s;
}

.timeline-item.outgoing .file-progress-fill { background: #fff; }

.file-status {
  font-size: 10px;
  font-family: var(--font-mono);
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-muted);
}

.timeline-item.outgoing .file-status { color: var(--accent-bright); }

/* =========================================================
   输入区
   ========================================================= */
.composer {
  padding: 24px 32px;
  background: var(--bg-panel);
  border-top: 1px solid var(--border);
}

.composer-inner {
  max-width: 896px;
  margin: 0 auto;
  display: flex;
  gap: 16px;
}

.composer-input-wrap {
  flex: 1;
  background: var(--bg-elev);
  border-radius: 12px;
  border: 1px solid var(--border-strong);
  display: flex;
  align-items: center;
  padding: 0 16px;
  transition: border-color 0.15s;
}

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

.composer-input-wrap svg {
  width: 18px;
  height: 18px;
  color: var(--text-muted);
  flex-shrink: 0;
  transition: color 0.15s;
}

.composer-input-wrap:focus-within svg { color: var(--accent); }

.composer-input {
  flex: 1;
  background: none;
  border: none;
  outline: none;
  padding: 14px 12px;
  font-size: 14px;
  color: var(--text-primary);
  resize: none;
  min-height: 52px;
  max-height: 160px;
  font-family: var(--font-sans);
}

.composer-input::placeholder { color: var(--text-muted); }
.composer-input:disabled { opacity: 0.5; cursor: not-allowed; }

.composer-keyhint {
  font-size: 10px;
  font-family: var(--font-mono);
  color: var(--text-muted);
  letter-spacing: 0.08em;
  background: var(--bg-panel);
  border: 1px solid var(--border-strong);
  padding: 4px 8px;
  border-radius: 4px;
  text-transform: uppercase;
  flex-shrink: 0;
}

.send-btn {
  width: 56px;
  height: 56px;
  border-radius: 12px;
  background: var(--accent);
  color: var(--text-inverse);
  display: grid;
  place-items: center;
  flex-shrink: 0;
  transition: all 0.15s;
}

.send-btn:hover:not(:disabled) {
  box-shadow: var(--shadow-lg);
  background: var(--accent-bright);
}

.send-btn:disabled {
  background: var(--bg-hover);
  color: var(--text-muted);
  cursor: not-allowed;
}

.send-btn svg { width: 20px; height: 20px; }

.composer-extra {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-top: 10px;
  max-width: 896px;
  margin-left: auto;
  margin-right: auto;
}

.attach-btn {
  font-size: 11px;
  font-family: var(--font-mono);
  letter-spacing: 0.08em;
  padding: 6px 12px;
  border-radius: 6px;
  background: var(--bg-elev);
  color: var(--text-secondary);
  border: 1px solid var(--border-strong);
  text-transform: uppercase;
  transition: all 0.15s;
}

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

.composer-hint {
  font-size: 10px;
  font-family: var(--font-mono);
  color: var(--text-muted);
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

/* =========================================================
   Setup 页（创建 / 加入房间）
   ========================================================= */
.setup-shell {
  display: grid;
  place-items: center;
  min-height: 100vh;
  padding: 40px 24px;
  background: var(--bg-base);
  overflow-y: auto;
}

.setup-card {
  width: 100%;
  max-width: 460px;
  text-align: center;
}

.setup-brand-block {
  margin-bottom: 40px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
}

.setup-brand-icon {
  width: 64px;
  height: 64px;
  border-radius: 16px;
  background: var(--bg-elev);
  border: 1px solid var(--border-strong);
  display: grid;
  place-items: center;
  box-shadow: var(--shadow-md);
  margin-bottom: 4px;
}

.setup-brand-icon svg { width: 32px; height: 32px; color: var(--accent); }

.setup-title {
  font-size: 28px;
  font-weight: 700;
  color: #fff;
  letter-spacing: -0.02em;
}

.setup-tagline {
  font-size: 13px;
  color: var(--text-secondary);
  max-width: 380px;
  margin: 0 auto;
}

.setup-form {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.setup-input-wrap {
  position: relative;
}

.setup-input-wrap svg {
  position: absolute;
  left: 16px;
  top: 50%;
  transform: translateY(-50%);
  width: 20px;
  height: 20px;
  color: var(--text-muted);
  transition: color 0.15s;
}

.setup-input-wrap:focus-within svg { color: var(--accent); }

.setup-input {
  width: 100%;
  background: var(--bg-elev);
  border: 1px solid var(--border-strong);
  border-radius: 8px;
  padding: 16px 16px 16px 48px;
  color: var(--text-primary);
  font-size: 14px;
  outline: none;
  transition: border-color 0.15s;
}

.setup-input::placeholder { color: var(--text-muted); }
.setup-input:focus { border-color: var(--accent); }

.btn-primary {
  width: 100%;
  background: var(--accent);
  color: var(--text-inverse);
  border-radius: 8px;
  padding: 16px;
  font-weight: 700;
  font-size: 14px;
  letter-spacing: 0.02em;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  transition: all 0.15s;
}

.btn-primary:hover { background: var(--accent-bright); box-shadow: var(--shadow-lg); }
.btn-primary:disabled { opacity: 0.4; cursor: not-allowed; }

.btn-primary svg { width: 16px; height: 16px; }

.divider {
  display: flex;
  align-items: center;
  gap: 12px;
  margin: 24px 0;
  font-size: 10px;
  font-family: var(--font-mono);
  color: var(--text-muted);
  letter-spacing: 0.15em;
  text-transform: uppercase;
}

.divider::before,
.divider::after {
  content: '';
  flex: 1;
  height: 1px;
  background: var(--border);
}

.share-card {
  margin-top: 32px;
  padding: 16px 20px;
  background: var(--bg-elev);
  border: 1px solid var(--border-strong);
  border-radius: 8px;
  text-align: center;
}

.share-label {
  font-size: 10px;
  font-family: var(--font-mono);
  color: var(--text-muted);
  letter-spacing: 0.15em;
  text-transform: uppercase;
  margin-bottom: 6px;
}

.share-code {
  font-family: var(--font-mono);
  font-size: 28px;
  font-weight: 700;
  letter-spacing: 0.12em;
  color: var(--accent);
  margin-bottom: 12px;
}

.share-link {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--text-secondary);
  word-break: break-all;
  margin-bottom: 12px;
}

.copy-btn {
  font-size: 11px;
  font-family: var(--font-mono);
  letter-spacing: 0.08em;
  padding: 8px 14px;
  border-radius: 6px;
  background: var(--accent);
  color: var(--text-inverse);
  text-transform: uppercase;
  font-weight: 600;
  transition: all 0.15s;
}

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

.code-input {
  display: flex;
  gap: 8px;
  justify-content: center;
}

.code-box {
  width: 48px;
  height: 60px;
  text-align: center;
  font-size: 24px;
  font-weight: 700;
  font-family: var(--font-mono);
  background: var(--bg-elev);
  border: 1px solid var(--border-strong);
  border-radius: 8px;
  color: var(--accent);
  outline: none;
  text-transform: uppercase;
  transition: all 0.15s;
}

.code-box:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-faint);
}

.network-warning {
  background: rgba(234, 179, 8, 0.06);
  border: 1px solid rgba(234, 179, 8, 0.2);
  border-radius: 8px;
  padding: 16px;
  margin-bottom: 16px;
  font-size: 13px;
  color: var(--text-secondary);
}

.network-warning strong {
  color: var(--warning);
  display: block;
  margin-bottom: 6px;
  font-size: 12px;
  font-family: var(--font-mono);
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.network-warning p { margin-bottom: 8px; }

.retry-btn {
  font-size: 11px;
  font-family: var(--font-mono);
  padding: 6px 12px;
  border-radius: 6px;
  background: var(--warning);
  color: #000;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

.retry-btn:hover { filter: brightness(1.1); }

.empty-state {
  text-align: center;
  color: var(--text-muted);
  font-size: 13px;
  padding: 60px 20px;
  font-family: var(--font-mono);
  letter-spacing: 0.05em;
}

/* =========================================================
   侧栏底部 Footer
   ========================================================= */
.lang-select {
  background: var(--bg-elev);
  border: 1px solid var(--border-strong);
  color: var(--text-secondary);
  padding: 4px 8px;
  border-radius: 6px;
  font-size: 11px;
  font-family: var(--font-mono);
  cursor: pointer;
  outline: none;
  letter-spacing: 0.04em;
}

.lang-select:focus { border-color: var(--accent); }

/* =========================================================
   模态框
   ========================================================= */
.modal {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.7);
  display: none;
  align-items: center;
  justify-content: center;
  z-index: 1000;
  padding: 24px;
}

.modal.show { display: flex; }

.modal-content {
  background: var(--bg-panel);
  border: 1px solid var(--border-strong);
  border-radius: 12px;
  padding: 32px;
  max-width: 560px;
  width: 100%;
  max-height: 80vh;
  overflow-y: auto;
  position: relative;
  box-shadow: var(--shadow-md);
}

.modal-content h2 {
  font-size: 14px;
  font-weight: 700;
  font-family: var(--font-mono);
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 20px;
}

.modal-content h3 {
  font-size: 11px;
  font-weight: 700;
  font-family: var(--font-mono);
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-secondary);
  margin-top: 20px;
  margin-bottom: 8px;
}

.modal-content p, .modal-content li {
  font-size: 13px;
  color: var(--text-secondary);
  line-height: 1.7;
  margin-bottom: 10px;
}

.modal-content ul { padding-left: 20px; }

.modal-content .close {
  position: absolute;
  top: 16px;
  right: 20px;
  font-size: 24px;
  color: var(--text-muted);
  cursor: pointer;
  line-height: 1;
}

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

/* =========================================================
   Toast
   ========================================================= */
.toast {
  position: fixed;
  top: 20px;
  right: 20px;
  background: var(--bg-elev);
  border: 1px solid var(--accent);
  color: var(--accent);
  padding: 12px 16px;
  border-radius: 8px;
  font-size: 12px;
  font-family: var(--font-mono);
  letter-spacing: 0.04em;
  z-index: 9999;
  box-shadow: var(--shadow-md);
  animation: slideInRight 0.3s ease;
}

.toast.error {
  border-color: var(--danger);
  color: var(--danger);
}

@keyframes slideInRight {
  from { transform: translateX(120%); opacity: 0; }
  to   { transform: translateX(0);    opacity: 1; }
}

/* =========================================================
   启动加载（Render 冷启动）
   ========================================================= */
.boot-loader {
  position: fixed;
  inset: 0;
  background: var(--bg-base);
  display: grid;
  place-items: center;
  z-index: 99999;
}

.boot-loader.is-hidden { display: none; }

.boot-spinner {
  width: 36px;
  height: 36px;
  border: 2px solid var(--border);
  border-top-color: var(--accent);
  border-radius: 50%;
  margin: 0 auto 16px;
  animation: spin 1s linear infinite;
}

@keyframes spin { to { transform: rotate(360deg); } }

.boot-title {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.2em;
  color: var(--accent);
  text-transform: uppercase;
  margin-bottom: 6px;
  text-align: center;
}

.boot-hint {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--text-muted);
  text-align: center;
}

.boot-block {
  text-align: center;
}

/* =========================================================
   通用
   ========================================================= */
.hidden { display: none !important; }

/* =========================================================
   响应式
   ========================================================= */
@media (max-width: 768px) {
  .app-shell { grid-template-columns: 1fr; }
  .sidebar { display: none; }
  .sidebar.is-mobile-open {
    display: flex;
    position: fixed;
    inset: 0;
    z-index: 100;
    width: 100%;
  }
  .session-topbar { padding: 0 16px; }
  .message-stream { padding: 16px; }
  .composer { padding: 16px; }
  .composer-keyhint { display: none; }
  .timeline-item { max-width: 90%; }
  .modal-content { padding: 20px; }
  .mobile-menu-btn {
    display: grid !important;
    place-items: center;
    width: 36px;
    height: 36px;
    border-radius: 6px;
    background: var(--bg-elev);
    color: var(--text-secondary);
    flex-shrink: 0;
  }
  .mobile-menu-btn svg { width: 18px; height: 18px; }
}

@media (min-width: 769px) {
  .mobile-menu-btn { display: none; }
}