/* App shell: the wallpaper layer, the two panes, and the drag handle between
   them. Nothing in here knows about messages. */

* { box-sizing: border-box; }

/* The UA stylesheet implements [hidden] as `display: none`, which ANY author
   `display` silently overrides. That bit once already: #chat-empty is a
   full-pane absolute overlay, so while "hidden" it stayed laid out on top of
   the message list and ate every wheel event. Enforce it globally. */
[hidden] { display: none !important; }

html, body {
  height: 100%;
  margin: 0;
  overflow: hidden;
}

body {
  font-family: var(--font);
  font-size: var(--font-size);
  color: var(--text);
  background: var(--bg-app);
  -webkit-font-smoothing: antialiased;
}

/* The wallpaper sits behind everything and never scrolls, so translucent
   panels blur against a stable image the way the desktop app does. */
#wallpaper {
  position: fixed;
  inset: 0;
  background: var(--wallpaper);
  background-size: cover;
  background-position: center;
  z-index: 0;
  transition: opacity var(--dur) var(--spring);
}
/* Dimming rides on top so it works for gradients and imported images alike. */
#wallpaper::after {
  content: "";
  position: absolute;
  inset: 0;
  background: #000;
  opacity: var(--wallpaper-dim);
  transition: opacity var(--dur) var(--spring);
}

#app {
  position: relative;
  z-index: 1;
  display: flex;
  height: 100%;
  align-items: stretch;
  gap: var(--inset);
  padding: var(--inset);
}

/* The sidebar holds its width while the window shrinks -- the message column
   takes the loss until it hits --chat-min, and only then does the sidebar
   give ground. flex-shrink on both, with min-widths, expresses exactly that. */
/* A rounded card sitting on the wallpaper, not a panel welded to the window
   edge -- the gap around it is what makes the background read as a background. */
#sidebar {
  flex: 0 1 var(--sidebar-w);
  min-width: var(--sidebar-min);
  display: flex;
  flex-direction: column;
  background: var(--panel);
  backdrop-filter: blur(var(--blur)) saturate(1.6);
  -webkit-backdrop-filter: blur(var(--blur)) saturate(1.6);
  border-radius: var(--radius-panel);
  box-shadow: var(--shadow);
  overflow: hidden;
  position: relative;
  z-index: 2;
}

#chat-pane {
  flex: 1 1 0;
  min-width: var(--chat-min);
  display: flex;
  flex-direction: column;
  position: relative;
  overflow: hidden;
}

/* ---- resize handle ----------------------------------------------------- */

/* Inside the sidebar's right edge, not out in the gap. The sidebar clips to
   its rounded corners with overflow:hidden, so anything positioned beyond that
   edge is invisible AND unclickable -- which is exactly what happened. */
#resizer {
  position: absolute;
  top: 0;
  right: 0;
  width: 9px;
  height: 100%;
  cursor: col-resize;
  z-index: 5;
  /* The visible line is a child so the hit area can be wider than it looks. */
}
#resizer::after {
  content: "";
  position: absolute;
  inset: 10px 3px 10px auto;
  right: 2px;
  width: 3px;
  border-radius: var(--radius-pill);
  background: var(--accent);
  opacity: 0;
  transition: opacity var(--dur-fast) var(--spring-fast);
}
#resizer:hover::after,
body.resizing #resizer::after { opacity: 0.55; }

/* Suppress hover/selection everywhere while a drag is in flight. */
body.resizing { cursor: col-resize; user-select: none; }
body.resizing * { pointer-events: none; }
body.resizing #resizer { pointer-events: auto; }

/* Width changes animate, except during a drag where they must track the
   pointer exactly. */
#sidebar { transition: flex-basis var(--dur) var(--spring); }
body.resizing #sidebar { transition: none; }

/* ---- shared bits ------------------------------------------------------- */

.icon-btn {
  display: grid;
  place-items: center;
  width: 34px;
  height: 34px;
  border: 0;
  border-radius: 50%;
  background: transparent;
  color: var(--text-dim);
  cursor: pointer;
  flex: none;
  transition: background var(--dur-fast) var(--spring-fast),
              color var(--dur-fast) var(--spring-fast),
              transform var(--dur-fast) var(--spring-fast);
}
.icon-btn:hover { background: var(--panel-hover); color: var(--text); }
.icon-btn:active { transform: scale(0.9); }
.icon-btn svg { width: 20px; height: 20px; }

.avatar {
  border-radius: 50%;
  object-fit: cover;
  flex: none;
  display: grid;
  place-items: center;
  font-weight: 600;
  color: #fff;
  overflow: hidden;
  user-select: none;
}
.avatar img { width: 100%; height: 100%; object-fit: cover; }

.scroll {
  overflow-y: auto;
  overscroll-behavior: contain;
  scrollbar-width: thin;
  scrollbar-color: var(--text-faint) transparent;
}
.scroll::-webkit-scrollbar { width: 8px; }
.scroll::-webkit-scrollbar-thumb {
  background: var(--text-faint);
  border-radius: 4px;
  background-clip: padding-box;
  border: 2px solid transparent;
}
.scroll::-webkit-scrollbar-track { background: transparent; }