.brand-block {
  display: flex;
  align-items: center;
  gap: 12px;
  width: 100%;
  border: 0;
  padding: 0;
  text-align: left;
  background: transparent;
  cursor: pointer;
  border-radius: 12px;
  transition: transform 0.18s ease, opacity 0.18s ease;
}

.brand-block:hover {
  transform: translateY(-1px);
}

.brand-block:focus-visible {
  outline: 3px solid var(--primary-border);
  outline-offset: 4px;
}

.mobile-menu-trigger {
  border: 0;
  padding: 0;
  background: transparent;
  cursor: pointer;
}

.mobile-menu-mark {
  width: 42px;
  height: 42px;
  display: grid;
  place-items: center;
  border-radius: 12px;
  background: linear-gradient(135deg, var(--primary), var(--green));
  box-shadow: var(--shadow-sm);
}

.mobile-menu-mark span {
  width: 17px;
  height: 2px;
  border-radius: 999px;
  background: #ffffff;
  box-shadow: 0 6px 0 #ffffff, 0 -6px 0 #ffffff;
}

.mobile-menu-close {
  display: none;
}

.brand-mark {
  width: 42px;
  height: 42px;
  display: grid;
  place-items: center;
  border-radius: 12px;
  color: #ffffff;
  background: linear-gradient(135deg, var(--primary), var(--green));
  font-size: 0.88rem;
  font-weight: 700;
  box-shadow: var(--shadow-sm);
}

.brand-name {
  color: var(--ink);
  font-size: 1rem;
  font-weight: 700;
  line-height: 1.1;
}

.brand-subtitle {
  color: var(--text-muted);
  font-size: 0.8rem;
  font-weight: 500;
}

.nav-links {
  display: grid;
  gap: 8px;
}

.nav-btn,
.rail-chip,
.mode-tab,
.prompt-card,
#send-btn,
.contact-link,
.theme-switch,
.stop-response-btn {
  transition: border-color 0.22s ease, background-color 0.22s ease, box-shadow 0.22s ease, transform 0.22s ease, color 0.22s ease;
}

.nav-btn {
  min-height: 40px;
  display: flex;
  align-items: center;
  gap: 10px;
  border: 1px solid transparent;
  border-radius: 10px;
  padding: 0 12px;
  background: transparent;
  color: var(--text-muted);
  cursor: pointer;
  font-weight: 650;
}

.nav-btn:hover,
.nav-btn.active {
  transform: translateY(-1px);
  color: var(--ink);
  border-color: var(--border);
  background: #ffffff;
  box-shadow: var(--shadow-sm);
}

body[data-theme="dark"] .nav-btn:hover,
body[data-theme="dark"] .nav-btn.active {
  color: var(--text-main);
  border-color: var(--primary-border);
  background: var(--primary-light);
}

.nav-icon {
  width: 22px;
  height: 22px;
  display: grid;
  place-items: center;
  border-radius: 7px;
  color: var(--primary);
  background: var(--primary-light);
  font-size: 0.86rem;
  font-weight: 700;
}

.rail-section {
  display: grid;
  gap: 8px;
}

.recents-list {
  display: grid;
  gap: 8px;
}

.recents-empty {
  border: 1px dashed var(--border);
  border-radius: 10px;
  padding: 10px 12px;
  color: var(--text-soft);
  background: var(--surface);
  font-size: 0.82rem;
  line-height: 1.35;
}

.rail-label {
  color: var(--text-soft);
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0;
  text-transform: uppercase;
}

.rail-chip {
  min-height: 38px;
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 0 12px;
  text-align: left;
  background: var(--surface);
  color: var(--text-main);
  cursor: pointer;
  font-weight: 600;
}

.rail-chip:hover {
  transform: translateY(-1px);
  border-color: var(--primary-border);
  background: var(--primary-light);
  box-shadow: var(--shadow-sm);
}

.recent-chat-chip {
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.recent-chat-chip.active {
  color: var(--primary);
  border-color: var(--primary-border);
  background: var(--primary-light);
  box-shadow: var(--shadow-sm);
}

body[data-theme="dark"] .recent-chat-chip.active {
  color: #ff9fbd;
  border-color: rgba(255, 143, 179, 0.44);
  background: #321b2a;
}

.rail-note {
  margin-top: auto;
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 14px;
  color: var(--text-muted);
  background: var(--surface);
  font-size: 0.84rem;
  line-height: 1.5;
}

.status-pill {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  min-height: 38px;
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 0 15px;
  color: var(--green);
  background: var(--surface);
  font-size: 0.88rem;
  font-weight: 700;
  text-decoration: none;
  white-space: nowrap;
  box-shadow: var(--shadow-sm);
}

.status-pill:hover,
.mobile-status-pill:hover {
  color: var(--green);
  border-color: rgba(23, 107, 85, 0.26);
  background: var(--green-soft);
}

.mobile-brand-actions {
  display: none;
}

.mobile-topbar-actions {
  display: none;
}

.mobile-status-pill {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  min-height: 34px;
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 0 13px;
  color: var(--green);
  background: var(--surface);
  box-shadow: var(--shadow-sm);
  font-size: 0.86rem;
  font-weight: 800;
  text-decoration: none;
  white-space: nowrap;
}

.top-actions {
  display: flex;
  align-items: center;
  gap: 10px;
}

.theme-switch {
  width: 68px;
  min-width: 68px;
  height: 38px;
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 4px;
  background: var(--surface);
  cursor: pointer;
  box-shadow: var(--shadow-sm);
}

.theme-switch:hover {
  transform: translateY(-1px);
  border-color: var(--primary-border);
}

.theme-switch:focus-visible {
  outline: 3px solid var(--primary-border);
  outline-offset: 3px;
}

.theme-switch-track {
  position: relative;
  display: block;
  width: 100%;
  height: 100%;
  border-radius: inherit;
  background: rgba(156, 18, 63, 0.12);
}

.theme-switch-thumb {
  position: absolute;
  top: 50%;
  left: 0;
  width: 27px;
  height: 27px;
  display: grid;
  place-items: center;
  border-radius: 50%;
  color: #ffffff;
  background: var(--primary);
  box-shadow: 0 8px 18px rgba(156, 18, 63, 0.25);
  transform: translateY(-50%);
  transition: transform 0.24s ease, background-color 0.24s ease, color 0.24s ease;
}

.theme-icon {
  display: block;
  font-size: 0.86rem;
  line-height: 1;
  transform: translateY(-0.5px);
}

body[data-theme="dark"] .theme-switch-track {
  background: rgba(255, 177, 200, 0.18);
}

body[data-theme="dark"] .theme-switch-thumb {
  color: #211924;
  background: #ffb1c8;
  transform: translate(31px, -50%);
}

.status-dot {
  position: relative;
  display: inline-block;
  flex: 0 0 auto;
  width: 9px;
  height: 9px;
  border-radius: 999px;
  background: var(--green);
  box-shadow:
    0 0 0 3px rgba(23, 107, 85, 0.12),
    0 0 10px rgba(23, 107, 85, 0.42);
  animation: liveDotBreath 1.55s ease-in-out infinite;
}

.status-dot::after {
  content: "";
  position: absolute;
  inset: -5px;
  border: 1px solid var(--green);
  border-radius: inherit;
  opacity: 0;
  animation: liveDotRing 1.55s ease-out infinite;
}

@keyframes liveDotBreath {
  0% {
    transform: scale(0.92);
    box-shadow:
      0 0 0 2px rgba(23, 107, 85, 0.1),
      0 0 8px rgba(23, 107, 85, 0.32);
  }
  50% {
    transform: scale(1.16);
    box-shadow:
      0 0 0 4px rgba(23, 107, 85, 0.16),
      0 0 14px rgba(23, 107, 85, 0.58);
  }
  100% {
    transform: scale(0.92);
    box-shadow:
      0 0 0 2px rgba(23, 107, 85, 0.1),
      0 0 8px rgba(23, 107, 85, 0.32);
  }
}

@keyframes liveDotRing {
  0% {
    opacity: 0.5;
    transform: scale(0.55);
  }
  70% {
    opacity: 0;
    transform: scale(1.9);
  }
  100% {
    opacity: 0;
    transform: scale(1.9);
  }
}

.welcome-panel {
  min-height: min(58vh, 560px);
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 28px;
  padding: clamp(22px, 5vw, 50px) clamp(6px, 3vw, 28px) 18px;
  animation: panelIn 520ms ease-out both;
}

.welcome-panel-hidden {
  display: none;
}

.welcome-copy {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
}

.welcome-copy h2 {
  max-width: 720px;
  color: var(--ink);
  font-family: "Fraunces", Georgia, serif;
  font-size: clamp(1.85rem, 4.2vw, 3.45rem);
  font-weight: 600;
  line-height: 1.04;
  letter-spacing: -0.02em;
}

.typing-headline {
  display: inline-flex;
  align-items: baseline;
  min-height: 1.08em;
}

.typing-text {
  display: inline-block;
  white-space: nowrap;
}

.typing-cursor {
  display: inline-block;
  width: 3px;
  height: 0.88em;
  margin-left: 3px;
  border-radius: 999px;
  background: var(--primary);
  transform: translateY(0.08em);
  animation: typingCursor 0.72s step-end infinite;
}

.welcome-copy p:not(.eyebrow) {
  max-width: 780px;
  margin-top: 18px;
  color: var(--text-muted);
  font-size: 1.02rem;
  line-height: 1.65;
}

.prompt-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 12px;
}

.prompt-card {
  min-height: 100px;
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 16px;
  text-align: left;
  color: var(--ink);
  background: var(--surface);
  cursor: pointer;
  font-size: 0.94rem;
  font-weight: 700;
  box-shadow: var(--shadow-sm);
  animation: cardIn 460ms ease-out both;
}

.prompt-card:nth-child(2) {
  animation-delay: 60ms;
}

.prompt-card:nth-child(3) {
  animation-delay: 120ms;
}

.prompt-card:nth-child(4) {
  animation-delay: 180ms;
}

.prompt-card span {
  display: block;
  margin-bottom: 7px;
  color: var(--primary);
  font-size: 0.72rem;
  font-weight: 700;
  text-transform: uppercase;
}

.prompt-card:hover {
  transform: translateY(-3px);
  border-color: var(--primary-border);
  background: var(--surface);
  box-shadow: var(--shadow-md);
}

.message-row {
  display: flex;
  flex-direction: column;
  width: 100%;
  margin-bottom: 22px;
  animation: messageIn 180ms ease-out both;
}

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

.message-row.bot {
  align-items: flex-start;
  margin-top: 4px;
}

.message-row.bot.is-loading {
  flex-direction: row;
  align-items: flex-start;
  gap: 8px;
}

.msg {
  max-width: min(780px, 88%);
  border-radius: 14px;
  padding: 14px 18px;
  font-size: 0.98rem;
  line-height: 1.6;
  word-break: break-word;
  box-shadow: var(--shadow-sm);
}

.msg.user {
  border-bottom-right-radius: 5px;
  color: var(--user-text);
  background: var(--user-bubble);
  white-space: pre-wrap;
}

.msg.bot {
  max-width: min(920px, 100%);
  border: 0;
  border-radius: 0;
  padding: 4px 0;
  color: var(--text-main);
  background: transparent;
  box-shadow: none;
  font-size: 1.14rem;
  line-height: 1.62;
  letter-spacing: -0.01em;
}

.gemini-sparkle-loader {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 0;
  color: var(--primary);
  font-size: 0.95rem;
  font-weight: 500;
}

.gemini-sparkle-loader .sparkle-symbol {
  display: inline-block;
  font-size: 1.15rem;
  color: var(--primary);
  animation: sparklePulse 1.4s ease-in-out infinite;
}

.gemini-sparkle-loader .sparkle-text {
  color: var(--text-muted);
  font-size: 0.92rem;
  animation: sparkleFade 1.4s ease-in-out infinite alternate;
}

@keyframes sparklePulse {
  0% {
    transform: scale(0.85) rotate(0deg);
    opacity: 0.5;
  }
  50% {
    transform: scale(1.25) rotate(45deg);
    opacity: 1;
    filter: drop-shadow(0 0 6px var(--primary-border));
  }
  100% {
    transform: scale(0.85) rotate(90deg);
    opacity: 0.5;
  }
}

@keyframes sparkleFade {
  0% { opacity: 0.45; }
  100% { opacity: 0.9; }
}

.msg.bot p {
  margin-bottom: 12px;
}

.msg.bot p:last-child {
  margin-bottom: 0;
}

.msg.bot ul,
.msg.bot ol {
  margin: 10px 0;
  padding-left: 22px;
}

.msg.bot li {
  margin-bottom: 5px;
}

.msg.bot h1,
.msg.bot h2,
.msg.bot h3 {
  margin: 22px 0 10px;
  color: var(--primary);
  font-family: 'Manrope', sans-serif;
  font-weight: 700;
  line-height: 1.25;
  letter-spacing: -0.01em;
}

.msg.bot h1:first-child,
.msg.bot h2:first-child,
.msg.bot h3:first-child {
  margin-top: 0;
}

.msg.bot h1 {
  font-size: 1.24rem;
}

.msg.bot h2,
.msg.bot h3 {
  font-size: 1.12rem;
}

.msg.bot strong {
  color: var(--ink);
  font-weight: 700;
}

.msg.bot a {
  display: inline-flex;
  align-items: center;
  min-height: 28px;
  margin: 2px 2px 2px 0;
  border: 1px solid var(--primary-border);
  border-radius: 999px;
  padding: 3px 10px;
  color: var(--primary);
  background: var(--primary-light);
  font-size: 0.86rem;
  font-weight: 650;
  text-decoration: none;
}

.msg.bot a:hover {
  border-color: var(--primary);
  background: #ffe7ee;
}

body[data-theme="dark"] .msg.bot a:hover {
  color: #ff9fbd;
  border-color: rgba(255, 143, 179, 0.5);
  background: rgba(160, 42, 86, 0.22);
}

.source-group {
  margin-top: 14px;
  padding-top: 12px;
  border-top: 1px solid var(--border);
}

.source-label {
  margin-bottom: 8px;
  color: var(--text-soft);
  font-size: 0.72rem;
  font-weight: 750;
  text-transform: uppercase;
}

.source-list {
  display: flex;
  flex-wrap: wrap;
  gap: 7px;
}

.source-list a {
  margin: 0;
}

.mode-tabs {
  width: min(100%, 860px);
  margin: -4px auto 6px;
  display: flex;
  gap: 8px;
  overflow-x: auto;
  padding: 4px;
  scrollbar-width: none;
}

.mode-tabs::-webkit-scrollbar {
  display: none;
}

.mode-tab {
  flex: 0 0 auto;
  min-height: 34px;
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 0 14px;
  background: var(--surface);
  color: var(--text-muted);
  cursor: pointer;
  font-size: 0.84rem;
  font-weight: 650;
}

.mode-tab:hover,
.mode-tab.active {
  transform: translateY(-1px);
  color: var(--primary);
  border-color: var(--primary-border);
  background: var(--primary-light);
  box-shadow: var(--shadow-sm);
}

body[data-theme="dark"] .mode-tab:hover,
body[data-theme="dark"] .mode-tab.active {
  color: #ff9fbd;
  border-color: rgba(255, 143, 179, 0.45);
  background: #321b2a;
}

#input-form {
  width: min(100%, 880px);
  min-height: 58px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: minmax(0, 1fr) 46px;
  align-items: end;
  gap: 10px;
  border: 1px solid var(--border-strong);
  border-radius: 18px;
  padding: 7px;
  background: #fff4f8;
  box-shadow: none;
  transition: border-color 0.18s ease, box-shadow 0.18s ease;
}

body[data-theme="dark"] #input-form {
  background: #241823;
}

#input-box {
  min-height: 44px;
  max-height: 25vh;
  border: 0;
  outline: 0;
  resize: none;
  overflow: hidden;
  padding: 11px 12px;
  color: var(--text-main);
  background: transparent;
  font-size: 0.96rem;
  line-height: 1.45;
  overflow-y: auto;
}

#input-box::placeholder {
  color: var(--text-soft);
}

#input-form:focus-within {
  border-color: var(--primary);
  box-shadow: 0 0 0 1px rgba(156, 18, 63, 0.18);
}

#send-btn {
  width: 46px;
  height: 44px;
  display: grid;
  place-items: center;
  border: 0;
  border-radius: 12px;
  color: #ffffff;
  background: var(--primary);
  cursor: pointer;
  font-weight: 800;
}

#send-btn:hover:not(:disabled) {
  background: var(--primary-hover);
}

#send-btn:disabled {
  opacity: 0.58;
  cursor: not-allowed;
}

#send-btn.is-stopping .stop-icon {
  font-size: 0.86rem;
  line-height: 1;
  display: inline-block;
}

.stop-response-btn {
  position: sticky;
  top: 8px;
  flex: 0 0 auto;
  width: 40px;
  height: 38px;
  min-height: 38px;
  display: grid;
  place-items: center;
  border: 0;
  border-radius: 11px;
  padding: 0;
  color: #ffffff;
  background: #9c123f;
  cursor: pointer;
  font-size: 0.72rem;
  font-weight: 800;
  box-shadow: 0 10px 20px rgba(156, 18, 63, 0.22);
}

.stop-response-btn:hover {
  transform: translateY(-1px);
  color: #ffffff;
  background: #870f36;
  box-shadow: 0 14px 28px rgba(135, 15, 54, 0.3);
}

.scroll-top-btn {
  position: fixed;
  right: 22px;
  bottom: 112px;
  z-index: 30;
  width: 38px;
  height: 38px;
  display: grid;
  place-items: center;
  border: 1px solid var(--border);
  border-radius: 999px;
  color: var(--primary);
  background: var(--surface);
  box-shadow: var(--shadow-sm);
  cursor: pointer;
  font-size: 1rem;
  font-weight: 800;
  opacity: 0;
  pointer-events: none;
  transform: translateY(8px);
  transition: opacity 0.18s ease, transform 0.18s ease, border-color 0.18s ease, background-color 0.18s ease;
}

.scroll-top-btn.visible {
  opacity: 1;
  pointer-events: auto;
  transform: translateY(0);
}

.scroll-top-btn:hover {
  border-color: var(--primary-border);
  background: var(--primary-light);
}

body[data-theme="dark"] .scroll-top-btn {
  color: #ff9fbd;
  background: #241823;
}

body[data-theme="dark"] .stop-response-btn {
  background: #fb7da8;
  box-shadow: 0 10px 20px rgba(251, 125, 168, 0.18);
}

body[data-theme="dark"] .stop-response-btn:hover {
  background: #f45f97;
  box-shadow: 0 14px 28px rgba(244, 95, 151, 0.28);
}

.prompt-card:disabled,
.rail-chip:disabled {
  opacity: 0.52;
  cursor: not-allowed;
  transform: none;
}

.send-icon {
  font-family: 'Manrope', -apple-system, BlinkMacSystemFont, sans-serif;
  font-size: 1.15rem;
  font-weight: 800;
  line-height: 1;
  display: block;
  transform: translateX(1px);
}

.authors-container {
  flex: 1;
  width: min(100%, 960px);
  margin: 0 auto;
  padding: 34px 24px;
  overflow-y: auto;
}

.authors-header {
  margin-bottom: 24px;
  text-align: center;
}

.authors-header h2 {
  color: var(--ink);
  font-size: clamp(1.7rem, 3vw, 2.35rem);
  font-weight: 700;
  letter-spacing: 0;
}

.authors-header p:not(.eyebrow) {
  margin-top: 8px;
  color: var(--text-muted);
}

.authors-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px;
  margin-bottom: 18px;
}

.author-card {
  display: flex;
  flex-direction: column;
  align-items: center;
  min-height: 390px;
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 26px 20px;
  text-align: center;
  background: var(--surface);
  box-shadow: var(--shadow-sm);
}

.author-photo-wrapper {
  width: 116px;
  height: 116px;
  margin-bottom: 16px;
  border: 4px solid var(--green-soft);
  border-radius: 50%;
  overflow: hidden;
  background: var(--surface-muted);
}

.author-photo {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.author-name {
  color: var(--ink);
  font-size: 1.2rem;
  font-weight: 700;
}

.author-role {
  margin: 5px 0 12px;
  color: var(--primary);
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0;
  text-transform: uppercase;
}

.author-desc {
  flex: 1;
  color: var(--text-muted);
  font-size: 0.9rem;
  line-height: 1.65;
}

.author-contacts {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 8px;
  margin-top: 18px;
}

.contact-link,
.github-link {
  color: var(--primary);
  font-weight: 700;
  text-decoration: none;
}

.contact-link {
  min-height: 28px;
  display: inline-flex;
  align-items: center;
  border: 1px solid var(--primary-border);
  border-radius: 999px;
  padding: 3px 10px;
  color: var(--primary);
  background: var(--primary-light);
  font-size: 0.84rem;
  font-weight: 650;
}

.contact-link:hover,
.github-link:hover {
  color: var(--primary-hover);
}

.contact-link:hover {
  border-color: var(--primary);
  background: #ffe7ee;
}

body[data-theme="dark"] .contact-link:hover {
  color: #ff9fbd;
  border-color: rgba(255, 143, 179, 0.5);
  background: rgba(160, 42, 86, 0.24);
}

.github-info-box {
  display: flex;
  align-items: center;
  gap: 14px;
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 18px 20px;
  background: var(--surface);
  box-shadow: var(--shadow-sm);
}

.github-icon svg {
  width: 24px;
  height: 24px;
  fill: var(--ink);
}

.github-info-box p {
  color: var(--text-muted);
  font-size: 0.92rem;
  line-height: 1.55;
}

@keyframes messageIn {
  0% {
    opacity: 0;
    transform: translateY(8px);
  }

  100% {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes panelIn {
  0% {
    opacity: 0;
    transform: translateY(12px);
  }

  100% {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes cardIn {
  0% {
    opacity: 0;
    transform: translateY(12px);
  }

  100% {
    opacity: 1;
    transform: translateY(0);
  }
}

@media (max-width: 900px) {
  .mobile-menu-trigger,
  .mobile-topbar-actions {
    display: flex;
    align-items: center;
  }

  .mobile-topbar-actions {
    justify-content: flex-end;
    gap: 10px;
    min-width: 0;
  }

  .brand-block {
    justify-content: flex-start;
    padding-right: 42px;
  }

  .brand-mark {
    width: 38px;
    height: 38px;
  }

  .mobile-menu-mark {
    width: 38px;
    height: 38px;
  }

  .mobile-menu-close {
    position: absolute;
    top: 20px;
    right: 16px;
    width: 32px;
    height: 32px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    border: 1px solid var(--border);
    border-radius: 999px;
    color: var(--text-muted);
    background: var(--surface);
    cursor: pointer;
    padding: 0;
    transition: border-color 0.18s ease, background-color 0.18s ease, color 0.18s ease;
  }

  .close-icon {
    position: relative;
    width: 12px;
    height: 12px;
    display: block;
  }

  .close-icon::before,
  .close-icon::after {
    content: "";
    position: absolute;
    top: 50%;
    left: 50%;
    width: 12px;
    height: 1.6px;
    border-radius: 999px;
    background: currentColor;
    transform-origin: center;
  }

  .close-icon::before {
    transform: translate(-50%, -50%) rotate(45deg);
  }

  .close-icon::after {
    transform: translate(-50%, -50%) rotate(-45deg);
  }

  .mobile-menu-close:hover {
    color: var(--primary);
    border-color: var(--primary-border);
    background: var(--primary-light);
  }

  .nav-links {
    display: flex;
    flex-direction: column;
    gap: 8px;
    overflow: visible;
  }

  .rail-section {
    display: grid;
    grid-template-columns: 1fr;
    gap: 8px;
  }

  .rail-label {
    grid-column: 1 / -1;
  }

  .rail-chip {
    text-align: left;
    white-space: nowrap;
  }

  .welcome-panel {
    min-height: min(54vh, 500px);
  }
}

@media (max-width: 640px) {
  .brand-block {
    min-width: 0;
    justify-content: flex-start;
  }

  .brand-block .brand-name {
    display: block;
  }

  .mobile-brand-actions {
    display: none;
  }

  .mobile-status-pill {
    min-height: 34px;
    padding: 0 13px;
    font-size: 0.84rem;
  }

  .nav-links {
    align-items: stretch;
    gap: 8px;
  }

  .nav-btn {
    min-height: 39px;
    align-items: center;
    justify-content: flex-start;
    gap: 9px;
    padding: 0 12px;
    line-height: 1;
  }

  .nav-btn:hover,
  .nav-btn.active {
    transform: none;
  }

  .nav-icon {
    width: 21px;
    height: 21px;
    line-height: 1;
    transform: translateY(0);
  }

  .rail-section {
    display: grid;
  }

  .prompt-card:nth-child(2),
  .prompt-card:nth-child(3) {
    display: none;
  }

  .welcome-panel {
    min-height: calc(100dvh - 238px);
    justify-content: center;
    gap: 16px;
    padding: 4px 2px 12px;
  }

  .welcome-copy h2 {
    font-size: 1.82rem;
    line-height: 1.12;
  }

  .welcome-copy p:not(.eyebrow) {
    margin-top: 12px;
    font-size: 0.92rem;
    line-height: 1.55;
  }

  .prompt-grid {
    grid-template-columns: 1fr;
    gap: 10px;
  }

  .prompt-card {
    min-height: 74px;
    padding: 14px 16px;
    border-radius: 13px;
  }

  .prompt-card span {
    margin-bottom: 6px;
    font-size: 0.66rem;
  }

  .authors-grid {
    grid-template-columns: 1fr;
  }

  .msg {
    max-width: 92%;
    border-radius: 12px;
    padding: 10px 13px;
    font-size: 0.84rem;
    line-height: 1.44;
  }

  .msg.bot {
    font-size: 0.95rem;
    line-height: 1.5;
  }

  .msg.bot h1,
  .msg.bot h2,
  .msg.bot h3 {
    margin: 10px 0 5px;
    line-height: 1.16;
  }

  .msg.bot h1 {
    font-size: 0.95rem;
  }

  .msg.bot h2,
  .msg.bot h3 {
    font-size: 0.88rem;
  }

  .msg.bot p {
    margin-bottom: 6px;
  }

  .msg.bot ul,
  .msg.bot ol {
    margin: 6px 0;
    padding-left: 16px;
  }

  .msg.bot li {
    margin-bottom: 3px;
  }

  .source-group {
    margin-top: 10px;
    padding-top: 9px;
  }

  .source-label {
    margin-bottom: 6px;
    font-size: 0.64rem;
  }

  .msg.bot a {
    min-height: 25px;
    padding: 2px 9px;
    font-size: 0.78rem;
  }

  .github-info-box {
    align-items: flex-start;
  }

  .theme-switch {
    width: 54px;
    min-width: 54px;
    height: 30px;
  }

  .theme-switch-thumb {
    width: 22px;
    height: 22px;
  }

  body[data-theme="dark"] .theme-switch-thumb {
    transform: translate(22px, -50%);
  }

  .mode-tabs {
    width: 100%;
    margin: 0 auto 5px;
    gap: 6px;
    padding: 2px 0 3px;
  }

  .mode-tab {
    min-height: 30px;
    padding: 0 12px;
    font-size: 0.78rem;
  }

  #input-form {
    width: 100%;
    max-width: calc(100vw - 24px);
    box-sizing: border-box;
    min-height: 50px;
    grid-template-columns: minmax(0, 1fr) 40px;
    align-items: center;
    gap: 7px;
    border-radius: 22px;
    padding: 5px 5px 5px 12px;
  }

  #input-box {
    min-height: 38px;
    padding: 9px 6px;
    font-size: 16px;
    line-height: 1.35;
  }

  #send-btn {
    width: 40px;
    height: 40px;
    border-radius: 14px;
    align-self: center;
  }

  .scroll-top-btn {
    right: 16px;
    bottom: 98px;
    width: 36px;
    height: 36px;
  }

  .disclaimer {
    display: none;
  }
}

@keyframes typingCursor {
  0%,
  100% {
    opacity: 0;
  }

  50% {
    opacity: 1;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    scroll-behavior: auto !important;
    transition-duration: 0.01ms !important;
  }

  .typing-cursor {
    display: none;
    animation: none !important;
  }
}

/* User Notification Toast */
.app-toast {
  position: fixed;
  bottom: 32px;
  left: 50%;
  transform: translateX(-50%) translateY(12px);
  background: var(--surface-card, #1a1a1a);
  color: var(--text-primary, #ffffff);
  border: 1px solid var(--primary-border, #444);
  padding: 10px 20px;
  border-radius: 999px;
  font-size: 0.88rem;
  font-weight: 550;
  box-shadow: 0 6px 24px rgba(0, 0, 0, 0.25);
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.4s ease-out, transform 0.4s ease-out;
  z-index: 99999;
  text-align: center;
  max-width: 90vw;
}

.app-toast.visible {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
  transition: opacity 0.15s ease-in, transform 0.15s ease-in;
}