:root {
  --bg: #17212b;
  --panel: #1f2c38;
  --panel-2: #22303d;
  --line: #2f4355;
  --text: #dce7f2;
  --muted: #8ca6bd;
  --accent: #4ea4f6;
  --accent-2: #3a8ad6;
  --error: #ff7f7f;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: "Segoe UI", Arial, sans-serif;
}

.screen {
  display: none;
  height: 100vh;
  min-height: 100dvh;
}

.screen.active {
  display: flex;
}

.auth-card {
  margin: auto;
  width: 360px;
  max-width: calc(100vw - 24px);
  background: var(--panel);
  border-radius: 14px;
  padding: 24px;
  border: 1px solid var(--line);
}

.muted {
  color: var(--muted);
}

.tabs {
  margin: 14px 0;
  display: flex;
  gap: 8px;
}

.tab {
  flex: 1;
}

.tab.active {
  background: var(--accent);
  color: #fff;
}

input, button, select {
  width: 100%;
  border-radius: 10px;
  border: 1px solid var(--line);
  background: var(--panel-2);
  color: var(--text);
  padding: 10px;
}

button {
  cursor: pointer;
}

button:hover {
  border-color: var(--accent);
}

.primary {
  background: var(--accent);
  border-color: var(--accent-2);
}

.ghost {
  background: transparent;
}

form {
  display: grid;
  gap: 10px;
}

.password-row {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 8px;
  align-items: center;
}

.password-toggle {
  width: auto;
  min-width: 44px;
  padding: 10px 12px;
}

.remember-row {
  display: flex;
  align-items: center;
  gap: 8px;
  color: var(--muted);
  font-size: 14px;
}

.remember-row input {
  width: auto;
}

.error {
  color: var(--error);
  min-height: 20px;
}

.hidden {
  display: none;
}

.sidebar {
  width: 360px;
  border-right: 1px solid var(--line);
  display: flex;
  flex-direction: column;
  background: #1a2633;
}

.sidebar-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px;
}

#logout-btn {
  width: auto;
  padding: 8px 12px;
}

.current-user {
  display: flex;
  gap: 10px;
  align-items: center;
  padding: 0 14px 14px;
}

.avatar {
  object-fit: cover;
  border-radius: 50%;
  background: var(--panel-2);
  border: 1px solid var(--line);
}

.avatar-lg {
  width: 44px;
  height: 44px;
}

.avatar-xs {
  width: 22px;
  height: 22px;
}

.toolbar {
  display: grid;
  gap: 8px;
  padding: 0 14px 14px;
}

.toolbar-row {
  display: flex;
  gap: 8px;
}

.toolbar-row button {
  flex: 1;
}

.chat-list {
  overflow: auto;
  border-top: 1px solid var(--line);
}

.mobile-chat-list-title {
  display: none;
}

.chat-item {
  padding: 12px 14px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.05);
  cursor: pointer;
  overflow: hidden;
}

.chat-item:hover, .chat-item.active {
  background: rgba(78, 164, 246, 0.18);
}

.chat-title {
  font-weight: 600;
  margin-bottom: 6px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.chat-preview {
  color: var(--muted);
  font-size: 13px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.chat-panel {
  flex: 1;
  display: flex;
  flex-direction: column;
}

.mobile-back-btn {
  position: fixed;
  top: 10px;
  left: 10px;
  z-index: 45;
  width: auto;
  padding: 8px 12px;
  border-radius: 999px;
  background: rgba(31, 44, 56, 0.95);
  border: 1px solid var(--line);
  box-shadow: 0 8px 18px rgba(0, 0, 0, 0.28);
}

.chat-header {
  border-bottom: 1px solid var(--line);
  padding: 16px;
  font-weight: 600;
  background: #1a2633;
}

.messages {
  flex: 1;
  overflow: auto;
  padding: 14px;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.msg {
  max-width: 70%;
  padding: 10px;
  border-radius: 10px;
  background: var(--panel);
  border: 1px solid var(--line);
}

.msg.me {
  align-self: flex-end;
  background: #2b5278;
}

.msg-meta {
  color: var(--muted);
  font-size: 12px;
  margin-bottom: 6px;
  display: flex;
  align-items: center;
  gap: 6px;
}

.msg-read {
  margin-top: 6px;
  font-size: 13px;
  letter-spacing: 0.5px;
  line-height: 1;
  color: var(--muted);
  text-align: right;
}

.message-form {
  border-top: 1px solid var(--line);
  display: grid;
  grid-template-columns: 48px 1fr 48px;
  gap: 10px;
  padding: 12px;
  align-items: center;
}

#message-input {
  min-width: 0;
}

.icon-btn {
  width: 48px;
  height: 42px;
  min-width: 48px;
  padding: 0;
  display: grid;
  place-items: center;
  font-size: 18px;
}

.message-image-preview {
  margin: 10px 12px 0;
  padding: 8px 10px;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: var(--panel);
}

.message-image-preview img {
  display: block;
  max-width: 240px;
  max-height: 180px;
  border-radius: 8px;
  margin-bottom: 6px;
}

.msg-image {
  display: block;
  max-width: 320px;
  max-height: 260px;
  border-radius: 8px;
  cursor: zoom-in;
}

.user-row {
  display: flex;
  align-items: center;
  gap: 8px;
}

.image-viewer {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.image-viewer-img {
  max-width: 100%;
  max-height: 70dvh;
  border-radius: 10px;
  object-fit: contain;
}

.image-viewer-link {
  color: var(--accent);
  text-decoration: none;
}

.toolbar-mobile-actions {
  display: grid;
  gap: 8px;
}

@media (max-width: 900px) {
  .sidebar {
    width: 300px;
  }
}

@media (max-width: 760px) {
  #chat-screen.screen.active {
    display: flex;
    flex-direction: column;
    height: 100dvh;
  }

  .sidebar {
    width: 100%;
    border-right: none;
    border-bottom: none;
    max-height: none;
    height: 100dvh;
  }

  #chat-screen:not(.mobile-chat-open) .chat-panel {
    display: none;
  }

  #chat-screen.mobile-chat-open .sidebar {
    display: none;
  }

  #chat-screen.mobile-chat-open .chat-panel {
    height: 100dvh;
  }

  #chat-screen.mobile-chat-open .chat-header {
    padding-left: 92px;
  }

  #chat-screen.mobile-chat-open .mobile-back-btn {
    display: inline-flex;
    align-items: center;
  }

  .mobile-chat-list-title {
    display: block;
    padding: 8px 14px 10px;
    color: var(--muted);
    font-size: 13px;
    border-top: 1px solid var(--line);
  }

  .toolbar-row {
    display: none;
  }

  #new-chat-btn {
    display: none;
  }

  #mobile-actions-btn {
    display: block;
    width: 100%;
  }

  .chat-list {
    flex: 1;
    min-height: 0;
  }

  .messages {
    padding: 10px;
  }

  .msg {
    max-width: 88%;
  }

  .message-form {
    grid-template-columns: 44px minmax(0, 1fr) 44px;
    gap: 8px;
    padding: 10px;
  }

  .modal {
    width: min(96vw, 560px);
    max-height: 88dvh;
    overflow: auto;
  }

  .search-result {
    flex-direction: column;
    align-items: flex-start;
    gap: 8px;
  }
}

@media (max-width: 480px) {
  .auth-card {
    padding: 16px;
  }

  #chat-screen.mobile-chat-open .chat-header {
    padding-left: 84px;
  }

  .mobile-back-btn {
    top: 8px;
    left: 8px;
    padding: 7px 10px;
    font-size: 13px;
  }

  .toolbar-row {
    grid-template-columns: 1fr;
  }

  .message-form {
    grid-template-columns: 40px minmax(0, 1fr) 40px;
    gap: 6px;
    padding: 8px;
  }

  .icon-btn {
    width: 40px;
    height: 38px;
    min-width: 40px;
    font-size: 16px;
  }

  .message-image-preview img {
    max-width: 100%;
    max-height: 180px;
  }

  .msg-image {
    max-width: 100%;
    max-height: 220px;
  }
}

.modal-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.55);
  display: flex;
}

.modal-backdrop.hidden {
  display: none;
}

.modal {
  width: min(600px, 95vw);
  margin: auto;
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 14px;
}

.modal-top {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.search-result {
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 10px;
  margin-bottom: 8px;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.chips {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.chip {
  padding: 6px 10px;
  border: 1px solid var(--line);
  border-radius: 999px;
  cursor: pointer;
}

.chip.selected {
  border-color: var(--accent);
  background: rgba(78, 164, 246, 0.2);
}