:root {
  --bg: #f7f8fa;
  --card: #ffffff;
  --border: #e5e7eb;
  --border-hover: #d1d5db;
  --text: #111827;
  --text-soft: #6b7280;
  --text-muted: #9ca3af;
  --accent: #7c3aed;
  --accent-soft: #ede9fe;
  --green: #10b981;
  --tag-neutral-bg: #f3f4f6;
  --tag-neutral-fg: #4b5563;
  --tag-event-bg: #d1fae5;
  --tag-event-fg: #047857;
  --tag-welcome-bg: #ede9fe;
  --tag-welcome-fg: #6d28d9;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  font-size: 14px;
  line-height: 1.45;
}

main {
  max-width: 960px;
  margin: 0 auto;
  padding: 16px 24px 64px;
}

/* topbar */
.topbar {
  max-width: 960px;
  margin: 16px auto 0;
  padding: 0 24px;
}
.topbar-inner {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 10px 20px;
  display: flex;
  align-items: center;
  gap: 12px;
  color: var(--text-soft);
}
.topbar .sep { color: var(--text-muted); }
.dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  display: inline-block;
}
.dot-active { background: var(--green); box-shadow: 0 0 0 3px rgba(16,185,129,0.15); }

/* stats */
.stats {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 12px;
  margin: 16px 0 24px;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 16px;
}
.stat-card {
  text-align: center;
  padding: 14px 10px;
  border-radius: 12px;
  background: var(--bg);
  border: 1px solid var(--border);
}
.stat-icon {
  color: var(--accent);
  font-size: 18px;
  height: 22px;
  display: flex;
  align-items: center;
  justify-content: center;
}
.stat-icon-online { color: var(--green); }
.stat-num {
  font-size: 28px;
  font-weight: 700;
  color: var(--accent);
  margin: 4px 0 2px;
}
.stat-label {
  color: var(--text-soft);
  font-size: 13px;
}

/* toolbar */
.toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 12px;
}
.filters { display: flex; gap: 8px; }
.filter-chip {
  border: 1px solid var(--border);
  background: var(--card);
  color: var(--text-soft);
  border-radius: 999px;
  padding: 6px 14px;
  cursor: pointer;
  font-size: 13px;
}
.filter-chip-active {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
}
.mark-read {
  color: var(--accent);
  text-decoration: none;
  font-size: 13px;
}
.mark-read:hover { text-decoration: underline; }

/* channels */
.channels {
  display: flex;
  flex-direction: column;
  gap: 10px;
}
.channel {
  display: grid;
  grid-template-columns: 48px 1fr auto;
  gap: 14px;
  align-items: start;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 14px 16px;
  transition: border-color 0.15s ease, transform 0.15s ease;
  cursor: pointer;
}
.channel:hover {
  border-color: var(--border-hover);
  transform: translateY(-1px);
}
.channel-icon {
  width: 36px;
  height: 36px;
  border-radius: 8px;
  background: var(--tag-neutral-bg);
  color: var(--text-soft);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 600;
  font-size: 16px;
}
.channel-head {
  display: flex;
  align-items: center;
  gap: 8px;
  flex-wrap: wrap;
}
.channel-name {
  margin: 0;
  font-size: 15px;
  font-weight: 600;
}
.channel-desc {
  margin: 4px 0 0;
  color: var(--text-soft);
}
.channel-meta {
  margin: 8px 0 0;
  color: var(--text-muted);
  font-size: 12px;
}
.channel-side { display: flex; align-items: flex-start; }
.post-count {
  background: var(--tag-neutral-bg);
  color: var(--text-soft);
  border-radius: 999px;
  padding: 3px 10px;
  font-size: 12px;
  white-space: nowrap;
}

/* tags */
.tag {
  display: inline-block;
  font-size: 11px;
  font-weight: 500;
  padding: 2px 8px;
  border-radius: 999px;
  border: 1px solid transparent;
}
.tag-neutral { background: var(--tag-neutral-bg); color: var(--tag-neutral-fg); }
.tag-event   { background: var(--tag-event-bg);   color: var(--tag-event-fg); }
.tag-welcome { background: var(--tag-welcome-bg); color: var(--tag-welcome-fg); }

/* identity in topbar */
.topbar-id {
  margin-left: auto;
  font-size: 12px;
  color: var(--accent);
  background: var(--accent-soft);
  padding: 2px 10px;
  border-radius: 999px;
}

/* empty state */
.empty {
  padding: 24px;
  text-align: center;
  color: var(--text-muted);
  background: var(--card);
  border: 1px dashed var(--border);
  border-radius: 12px;
}

/* channel detail view */
.channel-header {
  display: flex;
  align-items: center;
  gap: 12px;
  margin: 8px 0 4px;
}
.channel-header h2 { margin: 0; font-size: 20px; }
.channel-header-desc {
  margin: 0 0 16px;
  color: var(--text-soft);
}
.back {
  color: var(--text-soft);
  text-decoration: none;
  font-size: 13px;
}
.back:hover { color: var(--accent); }

/* posts */
.posts {
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-bottom: 16px;
}
.post {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 12px 16px;
}
.post-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  font-size: 12px;
  color: var(--text-soft);
  margin-bottom: 6px;
}
.post-author { font-weight: 600; color: var(--text); }
.post-date { color: var(--text-muted); }
.post-body {
  white-space: pre-wrap;
  word-break: break-word;
}

/* composer */
.composer {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 12px;
  display: flex;
  flex-direction: column;
  gap: 8px;
}
.composer textarea {
  width: 100%;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 10px;
  font-family: inherit;
  font-size: 14px;
  resize: vertical;
  background: var(--bg);
  color: var(--text);
}
.composer textarea:focus {
  outline: none;
  border-color: var(--accent);
}
.composer-actions {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
}
.composer-hint {
  color: var(--text-muted);
  font-size: 12px;
}
.composer-locked {
  background: var(--card);
  border: 1px dashed var(--border);
  border-radius: 12px;
  padding: 16px;
  text-align: center;
  color: var(--text-soft);
}
.btn-primary {
  background: var(--accent);
  color: #fff;
  border: none;
  border-radius: 8px;
  padding: 8px 16px;
  font-size: 14px;
  cursor: pointer;
}
.btn-primary:hover { filter: brightness(1.05); }
.btn-primary:disabled { opacity: 0.6; cursor: not-allowed; }

@media (max-width: 640px) {
  .stats { grid-template-columns: repeat(2, 1fr); }
  main { padding: 12px 16px 48px; }
  .topbar { padding: 0 16px; }
}