:root {
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;

  --color-bg: #0b0f19;
  --color-surface: #111827;
  --color-surface-hover: #1f2937;
  --color-border: #1f2937;
  --color-border-subtle: #374151;

  --color-text-main: #f9fafb;
  --color-text-muted: #9ca3af;
  --color-text-dim: #6b7280;

  --color-primary: #38bdf8;
  --color-primary-hover: #0ea5e9;
  --color-primary-dim: rgba(56, 189, 248, 0.15);

  --color-accent: #10b981;
  --color-accent-dim: rgba(16, 185, 129, 0.15);
  --color-warning: #f59e0b;
  --color-danger: #ef4444;

  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 14px;
}

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

body {
  font-family: var(--font-sans);
  background-color: var(--color-bg);
  color: var(--color-text-main);
  line-height: 1.5;
  height: 100vh;
  height: 100dvh;
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

/* Navbar */
.navbar {
  height: 60px;
  background-color: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 1.25rem;
  gap: 1rem;
  flex-shrink: 0;
}

.nav-brand {
  display: flex;
  align-items: center;
  gap: 0.65rem;
}

.logo-shield {
  font-size: 1.25rem;
}

.nav-brand h1 {
  font-size: 1.15rem;
  font-weight: 700;
  letter-spacing: -0.02em;
}

.badge-env {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  padding: 0.2rem 0.5rem;
  border-radius: 9999px;
  background-color: var(--color-accent-dim);
  color: var(--color-accent);
  border: 1px solid rgba(16, 185, 129, 0.3);
}

.badge-version {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  padding: 0.2rem 0.5rem;
  border-radius: 9999px;
  background-color: rgba(56, 189, 248, 0.12);
  color: var(--color-primary);
  border: 1px solid rgba(56, 189, 248, 0.3);
}

.nav-links {
  display: flex;
  gap: 0.5rem;
}

.nav-link-btn {
  font-size: 0.8rem;
  font-family: var(--font-mono);
  color: var(--color-text-muted);
  text-decoration: none;
  padding: 0.35rem 0.65rem;
  border-radius: var(--radius-sm);
  background-color: var(--color-surface-hover);
  border: 1px solid var(--color-border);
  transition: all 0.15s ease;
}

.nav-link-btn:hover {
  color: var(--color-text-main);
  border-color: var(--color-primary);
}

/* Session Badge */
.session-badge-wrapper {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  background-color: rgba(15, 23, 42, 0.7);
  border: 1px solid var(--color-border-subtle);
  border-radius: var(--radius-md);
  padding: 0.25rem 0.75rem;
}

.session-info-left {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.badge-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background-color: var(--color-accent);
  box-shadow: 0 0 8px var(--color-accent);
}

.session-name-input {
  background: transparent;
  border: 1px dashed transparent;
  border-radius: var(--radius-sm);
  color: var(--color-text-main);
  font-size: 0.85rem;
  font-weight: 600;
  padding: 0.2rem 0.4rem;
  width: 140px;
}

.session-name-input:hover {
  border-color: var(--color-border-subtle);
}

.session-name-input:focus {
  outline: none;
  background-color: var(--color-surface);
  border-color: var(--color-primary);
}

.session-info-right {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  color: var(--color-text-dim);
}

.btn-panic-wipe {
  background: transparent;
  border: 1px solid rgba(239, 68, 68, 0.3);
  color: var(--color-danger);
  border-radius: var(--radius-sm);
  padding: 0.15rem 0.4rem;
  font-size: 0.65rem;
  font-weight: 700;
  cursor: pointer;
  transition: all 0.15s ease;
}

.btn-panic-wipe:hover {
  background-color: var(--color-danger);
  color: #ffffff;
  box-shadow: 0 0 8px rgba(239, 68, 68, 0.5);
}

/* Custom Elements */
chat-creator, chat-joiner, chat-list, session-badge {
  display: block;
  width: 100%;
}

chat-header {
  display: block;
  width: 100%;
  flex-shrink: 0;
}

chat-room {
  flex: 1;
  display: flex;
  flex-direction: column;
  min-height: 0;
  width: 100%;
  overflow: hidden;
}

/* Main Layout */
.main-layout {
  flex: 1;
  display: flex;
  overflow: hidden;
}

/* Sidebar */
.sidebar {
  width: 360px;
  min-width: 320px;
  max-width: 400px;
  background-color: var(--color-surface);
  border-right: 1px solid var(--color-border);
  display: flex;
  flex-direction: column;
  padding: 1rem;
  gap: 1rem;
  overflow-y: auto;
  overflow-x: hidden;
  flex-shrink: 0;
  z-index: 2;
  box-sizing: border-box;
}

.action-card {
  background-color: rgba(11, 15, 25, 0.6);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 0.75rem;
  width: 100%;
  box-sizing: border-box;
}

.action-card h4 {
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-text-muted);
  margin-bottom: 0.5rem;
}

.inline-form {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  width: 100%;
}

.inline-form input {
  width: 100%;
  min-width: 0;
  box-sizing: border-box;
  background-color: var(--color-bg);
  border: 1px solid var(--color-border-subtle);
  border-radius: var(--radius-sm);
  color: var(--color-text-main);
  padding: 0.55rem 0.75rem;
  font-size: 0.85rem;
}

.inline-form input:focus {
  outline: none;
  border-color: var(--color-primary);
}

.inline-form button {
  width: 100%;
  background-color: var(--color-primary-dim);
  color: var(--color-primary);
  border: 1px solid rgba(56, 189, 248, 0.4);
  border-radius: var(--radius-sm);
  padding: 0.55rem 0.75rem;
  font-size: 0.8rem;
  font-weight: 600;
  cursor: pointer;
  text-align: center;
  transition: all 0.15s ease;
}

.inline-form button:hover {
  background-color: var(--color-primary);
  color: #0b0f19;
}

.join-status-msg, .create-status-msg {
  font-size: 0.75rem;
  margin-top: 0.4rem;
  min-height: 1rem;
}

.join-status-msg.error {
  color: var(--color-danger);
}

.join-status-msg.success {
  color: var(--color-accent);
}

/* Chat List */
.chat-list-wrapper {
  flex: 1;
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

.chat-list-header h3 {
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-text-muted);
  margin-bottom: 0.5rem;
}

.chat-items-container {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
  overflow-y: auto;
}

.chat-sidebar-item {
  background-color: rgba(11, 15, 25, 0.5);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  padding: 0.65rem 0.85rem;
  cursor: pointer;
  transition: all 0.15s ease;
}

.chat-sidebar-item:hover {
  background-color: var(--color-surface-hover);
  border-color: var(--color-border-subtle);
}

.chat-sidebar-item.active {
  background-color: var(--color-primary-dim);
  border-color: var(--color-primary);
}

.chat-sidebar-item.nuking-item {
  animation: nukeItemDisintegrate 0.8s forwards ease-out;
}

@keyframes nukeItemDisintegrate {
  0% { transform: scale(1); filter: brightness(1); opacity: 1; }
  30% { transform: scale(1.05); filter: brightness(2) drop-shadow(0 0 10px #ef4444); background-color: #ef4444; color: #fff; }
  100% { transform: scale(0.6) translateX(-60px); opacity: 0; max-height: 0; padding: 0; margin: 0; border: none; }
}

.chat-item-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.chat-item-title {
  font-size: 0.875rem;
  font-weight: 600;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  min-width: 0;
  flex: 1;
  margin-right: 0.5rem;
}

.chat-item-id {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  color: var(--color-text-muted);
  background-color: rgba(255, 255, 255, 0.05);
  padding: 0.15rem 0.35rem;
  border-radius: var(--radius-sm);
  flex-shrink: 0;
}

.chat-item-members {
  display: flex;
  align-items: center;
  gap: 0.35rem;
  margin-top: 0.25rem;
  font-size: 0.72rem;
  color: var(--color-text-muted);
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.chat-item-members .members-text {
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.empty-chat-hint {
  font-size: 0.8rem;
  color: var(--color-text-dim);
  font-style: italic;
  padding: 1rem 0;
  text-align: center;
}

/* Chat Viewport */
.chat-viewport {
  flex: 1;
  min-width: 0;
  display: flex;
  flex-direction: column;
  overflow: hidden;
  background-color: var(--color-bg);
  position: relative;
  z-index: 1;
}

/* Chat Header & TOTP Box */
.chat-header-panel {
  padding: 0.85rem 1.25rem;
  border-bottom: 1px solid var(--color-border);
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 0.75rem;
  background-color: var(--color-surface);
  flex-shrink: 0;
}

.chat-header-left {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.chat-header-title-group {
  display: flex;
  flex-direction: column;
  gap: 0.15rem;
}

.chat-header-title-row {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.chat-header-members {
  font-size: 0.72rem;
  color: var(--color-text-dim);
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  max-width: 340px;
}

.btn-back-chats {
  display: none;
  background-color: var(--color-surface-hover);
  color: var(--color-primary);
  border: 1px solid var(--color-border-subtle);
  border-radius: var(--radius-sm);
  padding: 0.35rem 0.65rem;
  font-size: 0.85rem;
  font-weight: 700;
  cursor: pointer;
  align-items: center;
  gap: 0.25rem;
  transition: all 0.15s ease;
}

.btn-back-chats:hover {
  background-color: rgba(56, 189, 248, 0.15);
  border-color: var(--color-primary);
}

.chat-room-title {
  font-size: 1.1rem;
  font-weight: 700;
}

.badge-code {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  background-color: var(--color-surface-hover);
  border: 1px solid var(--color-border-subtle);
  padding: 0.2rem 0.5rem;
  border-radius: var(--radius-sm);
  color: var(--color-primary);
}

.invite-token-box {
  background-color: rgba(11, 15, 25, 0.8);
  border: 1px solid var(--color-border-subtle);
  border-radius: var(--radius-md);
  padding: 0.4rem 0.75rem;
  min-width: 220px;
}

.invite-label {
  display: flex;
  justify-content: space-between;
  font-size: 0.65rem;
  text-transform: uppercase;
  color: var(--color-text-muted);
  margin-bottom: 0.2rem;
}

.seconds-left {
  font-family: var(--font-mono);
  font-weight: 700;
  color: var(--color-warning);
}

.invite-action-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.4rem;
}

.invite-key-val {
  font-family: var(--font-mono);
  font-size: 0.9rem;
  font-weight: 700;
  color: var(--color-primary);
  letter-spacing: 0.05em;
}

.btn-copy-invite {
  background-color: var(--color-surface-hover);
  color: var(--color-text-main);
  border: 1px solid var(--color-border-subtle);
  border-radius: var(--radius-sm);
  padding: 0.2rem 0.5rem;
  font-size: 0.7rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.15s ease;
}

.btn-copy-invite:hover {
  background-color: var(--color-primary);
  color: #0b0f19;
}

.btn-share-qr {
  background-color: rgba(56, 189, 248, 0.12);
  color: var(--color-primary);
  border: 1px solid rgba(56, 189, 248, 0.35);
  border-radius: var(--radius-sm);
  padding: 0.2rem 0.5rem;
  font-size: 0.7rem;
  font-weight: 700;
  cursor: pointer;
  transition: all 0.15s ease;
  white-space: nowrap;
}

.btn-share-qr:hover {
  background-color: var(--color-primary);
  color: #0b0f19;
}

.countdown-bar-bg {
  height: 3px;
  background-color: rgba(255, 255, 255, 0.1);
  border-radius: 9999px;
  overflow: hidden;
  margin-top: 0.35rem;
}

.countdown-progress {
  height: 100%;
  background: linear-gradient(90deg, var(--color-warning), var(--color-accent));
  transition: width 1s linear;
}

/* QR Code Modal Overlay & Dialog */
.qr-modal-backdrop {
  position: fixed;
  inset: 0;
  z-index: 10000;
  background-color: rgba(0, 0, 0, 0.85);
  backdrop-filter: blur(5px);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 1rem;
}

.qr-modal-dialog {
  background-color: var(--color-surface);
  border: 1px solid var(--color-border-subtle);
  border-radius: var(--radius-lg);
  box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.75);
  width: 380px;
  max-width: 100%;
  overflow: hidden;
  display: flex;
  flex-direction: column;
  animation: modalScaleIn 0.2s cubic-bezier(0.16, 1, 0.3, 1);
}

@keyframes modalScaleIn {
  0% { transform: scale(0.92); opacity: 0; }
  100% { transform: scale(1); opacity: 1; }
}

.qr-modal-header {
  padding: 1rem 1.25rem;
  border-bottom: 1px solid var(--color-border);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.qr-modal-header h3 {
  font-size: 1rem;
  font-weight: 700;
  color: var(--color-text-main);
}

.btn-close-qr {
  background: transparent;
  border: none;
  color: var(--color-text-muted);
  font-size: 1.5rem;
  line-height: 1;
  cursor: pointer;
  padding: 0.2rem 0.4rem;
  border-radius: var(--radius-sm);
}

.btn-close-qr:hover {
  color: #ffffff;
  background-color: rgba(255, 255, 255, 0.1);
}

.qr-modal-body {
  padding: 1.25rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.75rem;
  box-sizing: border-box;
  width: 100%;
}

.qr-canvas-wrapper {
  background-color: #ffffff;
  padding: 0.75rem;
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.35);
  margin: 0.25rem auto;
  box-sizing: border-box;
}

.qr-canvas-wrapper svg {
  display: block;
  max-width: 100%;
  height: auto;
}

/* Desktop QR sizing (210px) */
@media (min-width: 769px) {
  .qr-canvas-wrapper {
    width: 226px;
    height: 226px;
  }
}

.qr-countdown-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
  font-size: 0.75rem;
  color: var(--color-text-muted);
}

.qr-seconds {
  font-family: var(--font-mono);
  color: var(--color-warning);
  font-size: 0.85rem;
}

.qr-bar-bg {
  width: 100%;
  height: 3px;
  background-color: rgba(255, 255, 255, 0.1);
  border-radius: 9999px;
  overflow: hidden;
}

.qr-progress {
  height: 100%;
  background: linear-gradient(90deg, var(--color-warning), var(--color-accent));
  transition: width 1s linear;
}

.qr-url-row {
  display: flex;
  gap: 0.5rem;
  width: 100%;
  margin-top: 0.25rem;
}

.qr-url-input {
  flex: 1;
  min-width: 0;
  background-color: var(--color-bg);
  border: 1px solid var(--color-border-subtle);
  border-radius: var(--radius-sm);
  color: var(--color-text-muted);
  padding: 0.55rem 0.75rem;
  font-family: var(--font-mono);
  font-size: 0.8rem;
}

.btn-copy-qr-url {
  background-color: var(--color-surface-hover);
  color: var(--color-text-main);
  border: 1px solid var(--color-border-subtle);
  border-radius: var(--radius-sm);
  padding: 0.55rem 0.85rem;
  font-size: 0.75rem;
  font-weight: 700;
  cursor: pointer;
  white-space: nowrap;
  transition: all 0.15s ease;
}

.btn-copy-qr-url:hover {
  background-color: var(--color-primary);
  color: #0b0f19;
}

.btn-native-share {
  width: 100%;
  background-color: var(--color-primary-dim);
  color: var(--color-primary);
  border: 1px solid rgba(56, 189, 248, 0.4);
  border-radius: var(--radius-sm);
  padding: 0.65rem;
  font-size: 0.85rem;
  font-weight: 700;
  cursor: pointer;
  transition: all 0.15s ease;
}

.btn-native-share:hover {
  background-color: var(--color-primary);
  color: #0b0f19;
}

.qr-member-joined-toast {
  width: 100%;
  background-color: rgba(16, 185, 129, 0.2);
  border: 1px solid var(--color-accent);
  color: var(--color-accent);
  padding: 0.6rem;
  border-radius: var(--radius-sm);
  font-size: 0.875rem;
  font-weight: 700;
  text-align: center;
  animation: bannerPop 0.3s ease-out;
}

/* Chat Room & Messages */
.chat-room-container {
  flex: 1;
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

.messages-list {
  flex: 1;
  padding: 1.25rem;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.messages-empty-state {
  text-align: center;
  color: var(--color-text-dim);
  font-size: 0.9rem;
  margin: auto;
}

.message-bubble {
  max-width: 75%;
  padding: 0.65rem 0.9rem;
  border-radius: var(--radius-md);
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
  word-break: break-word;
}

.message-bubble.mine {
  align-self: flex-end;
  background-color: #0284c7;
  color: #ffffff;
  border-bottom-right-radius: 2px;
}

.message-bubble.theirs {
  align-self: flex-start;
  background-color: var(--color-surface);
  border: 1px solid var(--color-border-subtle);
  color: var(--color-text-main);
  border-bottom-left-radius: 2px;
}

.bubble-meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.7rem;
  gap: 1rem;
}

.message-bubble.mine .bubble-meta {
  color: rgba(255, 255, 255, 0.7);
}

.message-bubble.theirs .bubble-meta {
  color: var(--color-text-muted);
}

.bubble-author {
  font-weight: 600;
}

.bubble-time {
  font-family: var(--font-mono);
  font-size: 0.65rem;
}

.bubble-content {
  font-size: 0.9rem;
  line-height: 1.4;
}

/* Input Form */
.chat-input-form {
  padding: 0.85rem 1.25rem;
  border-top: 1px solid var(--color-border);
  background-color: var(--color-surface);
  display: flex;
  gap: 0.75rem;
}

.input-chat-message {
  flex: 1;
  background-color: var(--color-bg);
  border: 1px solid var(--color-border-subtle);
  border-radius: var(--radius-md);
  color: var(--color-text-main);
  padding: 0.7rem 1rem;
  font-size: 0.9rem;
}

.input-chat-message:focus {
  outline: none;
  border-color: var(--color-primary);
}

.btn-send-message {
  background-color: var(--color-primary);
  color: #0b0f19;
  border: none;
  border-radius: var(--radius-md);
  padding: 0.7rem 1.5rem;
  font-weight: 700;
  font-size: 0.875rem;
  cursor: pointer;
  transition: background-color 0.15s ease;
}

.btn-send-message:hover {
  background-color: var(--color-primary-hover);
}

.btn-send-message:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

/* Sound Toggle Button */
.btn-sound-toggle {
  background-color: var(--color-surface-hover);
  border: 1px solid var(--color-border-subtle);
  border-radius: var(--radius-sm);
  padding: 0.35rem 0.55rem;
  font-size: 0.85rem;
  cursor: pointer;
  transition: all 0.15s ease;
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

.btn-sound-toggle:hover {
  background-color: rgba(255, 255, 255, 0.1);
  border-color: var(--color-primary);
}

.btn-sound-toggle.muted {
  opacity: 0.6;
  filter: grayscale(0.8);
}

/* Nuke Button */
.btn-nuke-chat {
  background-color: rgba(239, 68, 68, 0.15);
  color: #ef4444;
  border: 1px solid rgba(239, 68, 68, 0.4);
  border-radius: var(--radius-sm);
  padding: 0.35rem 0.65rem;
  font-size: 0.75rem;
  font-weight: 700;
  cursor: pointer;
  align-items: center;
  gap: 0.35rem;
  transition: all 0.15s ease;
}

.btn-nuke-chat:hover {
  background-color: #ef4444;
  color: #ffffff;
  box-shadow: 0 0 12px rgba(239, 68, 68, 0.6);
}

/* Nuke Destruction Animations */
.chat-viewport.nuking {
  animation: nukeShake 0.6s infinite;
}

.chat-viewport.nuking .message-bubble {
  animation: burnDisintegrate 1.5s forwards ease-in-out;
}

@keyframes nukeShake {
  0%, 100% { transform: translate(0, 0); }
  10%, 50%, 90% { transform: translate(-6px, 3px); }
  20%, 60% { transform: translate(6px, -4px); }
  30%, 70% { transform: translate(-4px, -2px); }
  40%, 80% { transform: translate(5px, 3px); }
}

@keyframes burnDisintegrate {
  0% {
    filter: brightness(1);
    transform: scale(1);
    opacity: 1;
  }
  20% {
    filter: brightness(2) saturate(3) drop-shadow(0 0 15px #f97316);
    transform: scale(1.03);
  }
  60% {
    filter: brightness(4) drop-shadow(0 0 35px #ef4444);
    opacity: 0.8;
  }
  100% {
    filter: brightness(6);
    transform: scale(0.6) translateY(-40px);
    opacity: 0;
  }
}

/* Nuke Overlay */
.nuke-overlay {
  display: none;
  position: fixed;
  inset: 0;
  z-index: 9999;
  pointer-events: none;
  align-items: center;
  justify-content: center;
}

.nuke-overlay.active {
  display: flex;
  pointer-events: auto;
}

.nuke-flash {
  position: absolute;
  inset: 0;
  animation: nukeFlash 2.4s forwards ease-out;
}

@keyframes nukeFlash {
  0% {
    opacity: 0;
    background: transparent;
  }
  15% {
    opacity: 1;
    background: radial-gradient(circle, rgba(255, 255, 255, 0.98) 0%, rgba(249, 115, 22, 0.9) 45%, rgba(239, 68, 68, 0.95) 100%);
  }
  40% {
    opacity: 0.85;
    background: radial-gradient(circle, rgba(249, 115, 22, 0.8) 0%, rgba(15, 23, 42, 0.95) 80%);
  }
  100% {
    opacity: 0;
    background: transparent;
  }
}

.nuke-banner {
  position: relative;
  z-index: 2;
  background-color: rgba(15, 23, 42, 0.92);
  border: 2px solid #ef4444;
  border-radius: var(--radius-lg);
  padding: 2rem 3rem;
  text-align: center;
  box-shadow: 0 0 50px rgba(239, 68, 68, 0.8);
  animation: bannerPop 2.4s forwards ease-out;
}

@keyframes bannerPop {
  0% {
    transform: scale(0.6);
    opacity: 0;
  }
  15% {
    transform: scale(1.05);
    opacity: 1;
  }
  30% {
    transform: scale(1);
    opacity: 1;
  }
  80% {
    transform: scale(1);
    opacity: 1;
  }
  100% {
    transform: scale(0.8);
    opacity: 0;
  }
}

.nuke-icon {
  font-size: 3.5rem;
  display: block;
  margin-bottom: 0.5rem;
  animation: iconPulse 0.8s infinite alternate ease-in-out;
}

@keyframes iconPulse {
  0% { transform: scale(1); }
  100% { transform: scale(1.15); filter: drop-shadow(0 0 15px #ef4444); }
}

.nuke-title {
  font-size: 1.75rem;
  font-weight: 900;
  color: #ef4444;
  letter-spacing: 0.1em;
  margin-bottom: 0.5rem;
  text-shadow: 0 0 20px rgba(239, 68, 68, 0.8);
}

.nuke-subtitle {
  font-size: 0.95rem;
  color: var(--color-text-main);
  max-width: 400px;
}

/* Footer */
.app-footer {
  height: 28px;
  background-color: var(--color-surface);
  border-top: 1px solid var(--color-border);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.65rem;
  color: var(--color-text-dim);
  padding: 0 1rem;
}

/* ==========================================================================
   Mobile-First Responsive Layout (< 768px vs >= 769px)
   ========================================================================== */

@media (max-width: 768px) {
  .navbar {
    padding: 0.4rem 0.75rem;
    height: auto;
    min-height: 52px;
    gap: 0.5rem;
  }

  .nav-brand h1 {
    font-size: 1rem;
  }

  .nav-links {
    gap: 0.35rem;
  }

  .nav-link-btn {
    font-size: 0.7rem;
    padding: 0.25rem 0.45rem;
  }

  .session-badge-wrapper {
    padding: 0.2rem 0.45rem;
    gap: 0.4rem;
  }

  .session-name-input {
    width: 90px;
    font-size: 16px !important; /* Prevents iOS auto-zoom */
  }

  .session-info-right {
    font-size: 0.65rem;
    gap: 0.35rem;
  }

  .main-layout {
    position: relative;
    width: 100%;
    height: 100%;
    overflow: hidden;
  }

  /* Single-pane mobile navigation: show sidebar by default */
  .sidebar {
    width: 100% !important;
    min-width: 100% !important;
    max-width: 100% !important;
    border-right: none;
    display: flex !important;
  }

  .chat-viewport {
    display: none !important;
    width: 100%;
    height: 100%;
  }

  /* When viewing an active room on mobile */
  body.viewing-chat .sidebar {
    display: none !important;
  }

  body.viewing-chat .chat-viewport {
    display: flex !important;
  }

  .btn-back-chats {
    display: inline-flex !important;
  }

  /* Touch input sizing & iOS zoom prevention */
  .input-chat-message,
  .inline-form input,
  .qr-url-input {
    font-size: 16px !important;
  }

  .chat-input-form {
    padding: 0.6rem 0.85rem;
    padding-bottom: max(0.6rem, env(safe-area-inset-bottom));
  }

  .btn-send-message {
    padding: 0.6rem 1.15rem;
  }

  /* QR Modal on Mobile: almost fills screen */
  .qr-modal-dialog {
    width: min(92vw, 420px) !important;
    min-height: 75dvh !important;
    max-height: 90dvh !important;
    justify-content: space-between;
  }

  .qr-canvas-wrapper {
    width: min(76vw, 276px) !important;
    height: min(76vw, 276px) !important;
  }
}

@media (min-width: 769px) {
  .sidebar {
    width: 360px;
    min-width: 320px;
    max-width: 400px;
  }

  .chat-viewport {
    display: flex !important;
  }

  .btn-back-chats {
    display: none !important;
  }
}