:root {
  --bg: #f5f6f8;
  --panel: #ffffff;
  --text: #1c1f26;
  --muted: #6b7280;
  --line: #e2e5ea;
  --accent: #2f5bea;
  --accent-text: #ffffff;
  --mine: #e8eefe;
  --danger: #b42318;
  --ok: #067647;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #14161b;
    --panel: #1c1f26;
    --text: #eceef2;
    --muted: #9aa1ad;
    --line: #2c303a;
    --accent: #6c8cff;
    --accent-text: #0f1220;
    --mine: #23304f;
    --danger: #ff8a80;
    --ok: #5fd39a;
  }
}
* { box-sizing: border-box; }
html, body { height: 100%; }
body {
  margin: 0;
  font: 16px/1.45 system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  background: var(--bg);
  color: var(--text);
}
.hidden { display: none !important; }
.center { min-height: 100%; display: flex; align-items: center; justify-content: center; padding: 16px; }

.card {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 24px;
  width: 100%;
  max-width: 380px;
  display: flex;
  flex-direction: column;
  gap: 12px;
}
.card.wide { max-width: 520px; margin-bottom: 16px; }
h1 { margin: 0 0 4px; font-size: 1.5rem; }
h2 { margin: 0; font-size: 1.15rem; }

label { display: flex; flex-direction: column; gap: 4px; font-size: .9rem; color: var(--muted); }
input[type=text], input[type=email], input[type=password], textarea {
  font: inherit;
  color: var(--text);
  background: var(--bg);
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 10px 12px;
  width: 100%;
}
input:focus, textarea:focus, button:focus-visible { outline: 2px solid var(--accent); outline-offset: 1px; }

button, .upload-btn {
  font: inherit;
  cursor: pointer;
  border: 0;
  border-radius: 8px;
  padding: 10px 14px;
  background: var(--accent);
  color: var(--accent-text);
}
button.secondary, .upload-btn.secondary { background: transparent; color: var(--text); border: 1px solid var(--line); }
button.link { background: none; color: var(--accent); padding: 4px; text-decoration: underline; align-self: flex-start; }
button.small { padding: 6px 10px; font-size: .85rem; }
button.danger { background: transparent; color: var(--danger); border: 1px solid var(--line); }
button:disabled { opacity: .6; cursor: default; }

.msg { margin: 0; min-height: 1.2em; font-size: .9rem; color: var(--muted); }
.msg.error { color: var(--danger); }
.msg.ok { color: var(--ok); }
.hint { color: var(--muted); font-size: .9rem; margin: 4px 0 8px; }
.notice { margin: 16px; padding: 12px 14px; border: 1px solid var(--line); border-radius: 8px; background: var(--panel); }

/* App-layout */
.app { height: 100%; display: flex; flex-direction: column; max-width: 960px; margin: 0 auto; }
.topbar {
  display: flex; align-items: center; gap: 12px; flex-wrap: wrap;
  padding: 10px 16px; border-bottom: 1px solid var(--line); background: var(--panel);
}
.brand { flex: 1 1 auto; min-width: 0; }
.tabs { display: flex; gap: 4px; }
.tab { background: transparent; color: var(--muted); padding: 8px 12px; }
.tab.active { background: var(--mine); color: var(--text); }
.who { display: flex; align-items: center; gap: 8px; color: var(--muted); font-size: .9rem; }

.panel { flex: 1 1 auto; min-height: 0; display: flex; flex-direction: column; padding: 16px; overflow: auto; }
#tab-chat { overflow: hidden; }

/* Chat */
.chat-list { list-style: none; margin: 0; padding: 0; flex: 1 1 auto; overflow-y: auto; display: flex; flex-direction: column; gap: 8px; }
.msg-item { align-self: flex-start; max-width: 85%; background: var(--panel); border: 1px solid var(--line); border-radius: 12px; padding: 8px 12px; }
.msg-item.mine { align-self: flex-end; background: var(--mine); }
.msg-item .meta { font-size: .75rem; color: var(--muted); display: flex; gap: 8px; align-items: center; }
.msg-item .body { white-space: pre-wrap; overflow-wrap: anywhere; }
.msg-item .del { background: none; color: var(--muted); padding: 0 4px; font-size: .75rem; text-decoration: underline; }
.chat-form { display: flex; gap: 8px; padding-top: 12px; align-items: flex-end; }
.chat-form textarea { resize: none; }

/* Filer */
.files-head { display: flex; justify-content: space-between; align-items: center; gap: 8px; }
.files-list { list-style: none; margin: 0; padding: 0; display: flex; flex-direction: column; gap: 8px; }
.file-item { display: flex; align-items: center; gap: 12px; background: var(--panel); border: 1px solid var(--line); border-radius: 10px; padding: 10px 12px; }
.file-item .info { flex: 1 1 auto; min-width: 0; }
.file-item .name { overflow-wrap: anywhere; }
.file-item .sub { font-size: .8rem; color: var(--muted); }

@media (max-width: 560px) {
  .who #who-name { display: none; }
  .msg-item { max-width: 95%; }
}