.chat-toggle,
.chat-panel,
.chat-panel * {
  box-sizing: border-box;
}

.chat-toggle {
  position: fixed;
  z-index: 9998;
  top: auto;
  right: auto;
  bottom: max(20px, env(safe-area-inset-bottom));
  left: 82px;
  display: grid;
  width: 50px;
  min-width: 50px;
  height: 50px;
  min-height: 50px;
  place-items: center;
  margin: 0;
  padding: 0;
  border: 1px solid var(--line, rgba(148, 163, 184, 0.32));
  border-radius: 50%;
  background: var(--control-bg, var(--panel-strong, rgba(15, 23, 42, 0.92)));
  color: var(--text, #f8fafc);
  box-shadow: var(--shadow, 0 12px 34px rgba(0, 0, 0, 0.28));
  font: inherit;
  font-size: 23px;
  line-height: 1;
  cursor: pointer;
  backdrop-filter: blur(12px);
  transition: transform 0.18s ease, background-color 0.2s ease, color 0.2s ease;
}

.chat-toggle:hover {
  background: var(--surface-soft, var(--panel, rgba(30, 41, 59, 0.96)));
  transform: translateY(-2px) rotate(-6deg);
}

.chat-toggle:active {
  transform: scale(0.96);
}

.chat-toggle.has-mention::after {
  position: absolute;
  top: 1px;
  right: 1px;
  width: 12px;
  height: 12px;
  border: 2px solid var(--surface, #ffffff);
  border-radius: 50%;
  background: #ef4444;
  box-shadow: 0 0 0 2px rgba(239, 68, 68, 0.18);
  content: "";
}

.chat-panel[hidden] {
  display: none;
}

.chat-panel {
  position: fixed;
  z-index: 9997;
  right: auto;
  bottom: max(82px, calc(env(safe-area-inset-bottom) + 72px));
  left: 20px;
  display: grid;
  grid-template-rows: auto minmax(0, 1fr) auto;
  width: min(390px, calc(100vw - 40px));
  height: min(650px, calc(100dvh - 112px));
  min-height: 360px;
  max-height: calc(100dvh - 112px);
  overflow: hidden;
  resize: vertical;
  border: 1px solid var(--line, rgba(148, 163, 184, 0.32));
  border-radius: 16px;
  background: var(--surface, var(--panel-strong, #ffffff));
  color: var(--text, #17202a);
  box-shadow: 0 24px 70px rgba(0, 0, 0, 0.36);
  opacity: 0;
  transform: translateY(14px) scale(0.98);
  transform-origin: left bottom;
  transition: opacity 0.2s ease, transform 0.2s ease;
}

.chat-panel.is-open {
  opacity: 1;
  transform: translateY(0) scale(1);
}

.chat-panel-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 13px 14px;
  border-bottom: 1px solid var(--line, rgba(148, 163, 184, 0.32));
  background: var(--surface-soft, rgba(148, 163, 184, 0.09));
}

.chat-panel-title {
  display: grid;
  gap: 2px;
  min-width: 0;
}

.chat-title-row {
  display: flex;
  flex-wrap: wrap;
  gap: 7px;
  align-items: center;
}

.chat-panel-title strong {
  font-size: 16px;
}

.chat-panel-title span {
  overflow: hidden;
  color: var(--muted, #64748b);
  font-size: 12px;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.chat-online {
  display: inline-flex;
  gap: 5px;
  align-items: center;
  min-height: 23px;
  padding: 3px 7px;
  border-radius: 999px;
  background: rgba(22, 163, 74, 0.12);
  color: #15803d !important;
  font-size: 11px !important;
  font-weight: 800;
}

.chat-online i {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: #22c55e;
  box-shadow: 0 0 0 3px rgba(34, 197, 94, 0.14);
}

.chat-close {
  display: grid;
  width: 36px;
  min-width: 36px;
  height: 36px;
  min-height: 36px;
  place-items: center;
  padding: 0;
  border: 1px solid var(--line, rgba(148, 163, 184, 0.32));
  border-radius: 50%;
  background: var(--control-bg, transparent);
  color: var(--text, inherit);
  font: inherit;
  font-size: 18px;
  cursor: pointer;
}

.chat-close:hover {
  background: var(--surface-soft, rgba(148, 163, 184, 0.14));
  transform: none;
}

.chat-message-list {
  display: grid;
  align-content: start;
  gap: 10px;
  min-height: 0;
  padding: 14px;
  overflow-y: auto;
  overscroll-behavior: contain;
  scrollbar-color: color-mix(in srgb, var(--accent, #2563eb) 58%, #64748b) transparent;
  scrollbar-width: thin;
}

.chat-message-list::-webkit-scrollbar,
.chat-input::-webkit-scrollbar {
  width: 9px;
  height: 9px;
}

.chat-message-list::-webkit-scrollbar-track,
.chat-input::-webkit-scrollbar-track {
  border-radius: 999px;
  background: transparent;
}

.chat-message-list::-webkit-scrollbar-button,
.chat-input::-webkit-scrollbar-button {
  display: none;
  width: 0;
  height: 0;
}

.chat-message-list::-webkit-scrollbar-thumb,
.chat-input::-webkit-scrollbar-thumb {
  min-height: 40px;
  border: 2px solid transparent;
  border-radius: 999px;
  background: color-mix(in srgb, var(--accent, #2563eb) 58%, #64748b);
  background-clip: content-box;
}

.chat-message-list::-webkit-scrollbar-thumb:hover,
.chat-input::-webkit-scrollbar-thumb:hover {
  background: var(--accent, #2563eb);
  background-clip: content-box;
}

.chat-message-list::-webkit-scrollbar-corner,
.chat-input::-webkit-scrollbar-corner {
  background: transparent;
}

.chat-empty {
  align-self: center;
  padding: 30px 12px;
  color: var(--muted, #64748b);
  text-align: center;
  font-size: 14px;
}

.chat-message {
  display: grid;
  gap: 4px;
  justify-items: start;
}

.chat-message.is-own {
  justify-items: end;
}

.chat-message-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 5px;
  align-items: center;
  max-width: 88%;
  color: var(--muted, #64748b);
  font-size: 11px;
}

.chat-message-meta b {
  color: var(--text, inherit);
  font-size: 12px;
}

.chat-edited {
  font-style: italic;
}

.chat-role {
  display: inline-flex;
  align-items: center;
  min-height: 20px;
  padding: 2px 6px;
  border-radius: 999px;
  background: rgba(59, 130, 246, 0.13);
  color: #2563eb;
  font-size: 10px;
  font-weight: 800;
}

.chat-role.is-teacher {
  background: rgba(180, 83, 9, 0.14);
  color: #b45309;
}

.chat-role.is-admin {
  background: rgba(147, 51, 234, 0.14);
  color: #9333ea;
}

.chat-message-bubble {
  max-width: 88%;
  margin: 0;
  padding: 9px 11px;
  border: 1px solid var(--line, rgba(148, 163, 184, 0.28));
  border-radius: 5px 13px 13px;
  background: var(--surface-soft, rgba(148, 163, 184, 0.12));
  overflow-wrap: anywhere;
  white-space: pre-wrap;
  font-size: 14px;
  line-height: 1.55;
}

.chat-mention {
  display: inline;
  padding: 1px 4px;
  border-radius: 5px;
  background: color-mix(in srgb, var(--accent, #2563eb) 16%, transparent);
  color: var(--accent, #2563eb);
  font-weight: 900;
}

.chat-mention.is-all {
  background: color-mix(in srgb, #f59e0b 18%, transparent);
  color: #b45309;
}

.chat-message.is-own .chat-message-bubble {
  border-color: color-mix(in srgb, var(--accent, #2563eb) 42%, transparent);
  border-radius: 13px 5px 13px 13px;
  background: color-mix(in srgb, var(--accent, #2563eb) 13%, var(--surface, #ffffff));
}

.chat-message-action {
  min-height: 24px;
  padding: 2px 7px;
  border: 0;
  border-radius: 999px;
  background: transparent;
  color: var(--accent, #2563eb);
  font: inherit;
  font-size: 11px;
  cursor: pointer;
}

.chat-message-action.is-danger {
  color: var(--bad, #dc2626);
}

.chat-message-action:hover {
  background: color-mix(in srgb, currentColor 10%, transparent);
  transform: none;
}

.chat-reaction-row {
  position: relative;
  display: flex;
  flex-wrap: wrap;
  gap: 5px;
  align-items: center;
  max-width: 88%;
}

.chat-reaction-row:empty {
  display: none;
}

.chat-message.is-own .chat-reaction-row {
  justify-content: flex-end;
}

.chat-reaction,
.chat-reaction-add,
.chat-reaction-picker button {
  min-width: 0;
  min-height: 27px;
  padding: 3px 7px;
  border: 1px solid var(--line, rgba(148, 163, 184, 0.28));
  border-radius: 999px;
  background: var(--control-bg, rgba(148, 163, 184, 0.08));
  color: var(--text, inherit);
  font: inherit;
  font-size: 12px;
  line-height: 1;
  cursor: pointer;
}

.chat-reaction:hover:not(:disabled),
.chat-reaction-add:hover,
.chat-reaction-picker button:hover {
  border-color: var(--accent, #2563eb);
  background: color-mix(in srgb, var(--accent, #2563eb) 10%, transparent);
  transform: translateY(-1px);
}

.chat-reaction.is-selected {
  border-color: var(--accent, #2563eb);
  background: color-mix(in srgb, var(--accent, #2563eb) 16%, transparent);
  color: var(--accent, #2563eb);
  font-weight: 900;
}

.chat-reaction:disabled {
  cursor: default;
  opacity: 0.78;
}

.chat-reaction-picker-wrap {
  position: relative;
  display: inline-flex;
}

.chat-reaction-picker[hidden] {
  display: none;
}

.chat-reaction-picker {
  position: absolute;
  z-index: 4;
  bottom: calc(100% + 6px);
  left: 0;
  display: flex;
  gap: 4px;
  padding: 6px;
  border: 1px solid var(--line, rgba(148, 163, 184, 0.32));
  border-radius: 10px;
  background: var(--surface, var(--panel-strong, #ffffff));
  box-shadow: 0 12px 30px rgba(0, 0, 0, 0.25);
}

.chat-message.is-own .chat-reaction-picker {
  right: 0;
  left: auto;
}

.chat-reaction-picker button {
  width: 31px;
  padding: 0;
  font-size: 16px;
}

.chat-message-action.is-danger:hover {
  background: rgba(220, 38, 38, 0.1);
}

.chat-composer {
  display: grid;
  gap: 8px;
  padding: 12px;
  border-top: 1px solid var(--line, rgba(148, 163, 184, 0.32));
  background: var(--surface, var(--panel-strong, #ffffff));
}

.chat-input {
  width: 100%;
  min-height: 66px;
  max-height: 130px;
  resize: vertical;
  padding: 9px 10px;
  border: 1px solid var(--line, rgba(148, 163, 184, 0.32));
  border-radius: 9px;
  outline: none;
  background: var(--control-bg, rgba(148, 163, 184, 0.08));
  color: var(--text, inherit);
  font: inherit;
  font-size: 14px;
  line-height: 1.45;
  scrollbar-color: color-mix(in srgb, var(--accent, #2563eb) 58%, #64748b) transparent;
  scrollbar-width: thin;
}

.chat-input:focus {
  border-color: var(--accent, #2563eb);
  box-shadow: 0 0 0 3px color-mix(in srgb, var(--accent, #2563eb) 16%, transparent);
}

.chat-input:disabled {
  cursor: not-allowed;
  opacity: 0.65;
}

.chat-composer-actions {
  display: flex;
  align-items: center;
  gap: 8px;
}

.chat-character-count {
  margin-right: auto;
  color: var(--muted, #64748b);
  font-size: 11px;
}

.chat-login-link,
.chat-refresh,
.chat-send {
  display: inline-grid;
  min-height: 36px;
  place-items: center;
  padding: 0 12px;
  border: 0;
  border-radius: 8px;
  background: var(--accent, #2563eb);
  color: #ffffff;
  font: inherit;
  font-size: 13px;
  font-weight: 800;
  text-decoration: none;
  cursor: pointer;
}

.chat-refresh {
  border: 1px solid var(--line, rgba(148, 163, 184, 0.32));
  background: var(--control-bg, rgba(148, 163, 184, 0.08));
  color: var(--text, inherit);
}

.chat-refresh:disabled,
.chat-send:disabled {
  cursor: not-allowed;
  opacity: 0.55;
}

.chat-login-link:hover,
.chat-refresh:hover:not(:disabled),
.chat-send:hover:not(:disabled) {
  filter: brightness(0.94);
  transform: translateY(-1px);
}

.chat-feedback {
  min-height: 17px;
  margin: 0;
  color: var(--muted, #64748b);
  font-size: 12px;
}

.chat-feedback.is-error {
  color: var(--bad, #dc2626);
}

@media (max-width: 720px) {
  .chat-toggle {
    bottom: max(12px, env(safe-area-inset-bottom));
    left: 68px;
    width: 46px;
    min-width: 46px;
    height: 46px;
    min-height: 46px;
  }

  .chat-panel {
    bottom: max(70px, calc(env(safe-area-inset-bottom) + 60px));
    left: 12px;
    width: calc(100vw - 24px);
    height: min(620px, calc(100dvh - 92px));
    min-height: 300px;
    max-height: calc(100dvh - 92px);
  }
}

@media (prefers-reduced-motion: reduce) {
  .chat-toggle,
  .chat-panel {
    transition: none;
  }
}