@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700&family=JetBrains+Mono:wght@400;500&display=swap');

:root {
  /* --- Horizon Design System tokens --- */
  --primary-50: #EFF6FF;
  --primary-100: #DBEAFE;
  --primary-200: #BFDBFE;
  --primary-400: #60A5FA;
  --primary-600: #2563EB;
  --primary-700: #1D4ED8;
  --primary-900: #1E3A8A;
  --neutral-0: #FFFFFF;
  --neutral-50: #F8FAFC;
  --neutral-100: #F1F5F9;
  --neutral-200: #E2E8F0;
  --neutral-400: #94A3B8;
  --neutral-600: #475569;
  --neutral-800: #1E293B;
  --neutral-900: #0F172A;
  --accent-yellow-300: #FDE047;
  --accent-yellow-400: #FACC15;
  --accent-orange-400: #FB923C;
  --accent-orange-600: #EA580C;
  --success-500: #22C55E;
  --info-500: #3B82F6;
  --error-500: #EF4444;
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-full: 9999px;
  --shadow-sm: 0 1px 2px rgba(15,23,42,0.06), 0 1px 3px rgba(15,23,42,0.08);
  --shadow-md: 0 4px 10px rgba(15,23,42,0.10);
  --ease: cubic-bezier(0.2, 0, 0, 1);
}

* { box-sizing: border-box; }

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

body {
  font-family: 'Inter', 'Google Sans', ui-sans-serif, sans-serif;
  color: var(--neutral-800);
  background: var(--neutral-50);
}

#app {
  display: grid;
  grid-template-columns: 232px 1fr;
  grid-template-rows: auto 1fr;
  min-height: 100vh;
}

/* ---------- Top bar ---------- */
.topbar {
  grid-column: 1 / -1;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 24px;
  border-bottom: 1px solid var(--neutral-200);
  background: var(--neutral-0);
  position: sticky;
  top: 0;
  z-index: 10;
}
.wordmark { font-size: 1.125rem; font-weight: 700; color: var(--neutral-900); }
.topbar-right { display: flex; align-items: center; gap: 16px; }

.avatar-stack { display: flex; cursor: pointer; position: relative; }
.av {
  width: 28px; height: 28px; border-radius: var(--radius-full);
  display: flex; align-items: center; justify-content: center;
  font-size: 0.75rem; font-weight: 600; color: #fff;
  border: 2px solid var(--neutral-0);
}
.avatar-stack .av { margin-left: -8px; }
.avatar-stack .av:first-child { margin-left: 0; }

.people-popover {
  display: none;
  position: absolute; top: 38px; right: 0;
  background: var(--neutral-0);
  border: 1px solid var(--neutral-200);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-md);
  padding: 8px;
  width: 190px;
  z-index: 20;
}
.people-popover.open { display: block; }
.people-popover .prow {
  display: flex; align-items: center; gap: 8px;
  padding: 8px 6px; font-size: 0.875rem; color: var(--neutral-800);
  border-radius: var(--radius-sm);
}
.people-popover .prow:hover { background: var(--neutral-100); }
.people-popover .prow .av { margin-left: 0; width: 22px; height: 22px; font-size: 0.625rem; }

/* ---------- Buttons ---------- */
.btn {
  font-family: inherit;
  font-size: 0.875rem;
  font-weight: 500;
  border-radius: var(--radius-md);
  padding: 8px 16px;
  cursor: pointer;
  border: none;
  transition: background 150ms var(--ease);
}
.btn-primary { background: var(--primary-600); color: #fff; }
.btn-primary:hover { background: var(--primary-700); }
.btn-secondary { background: var(--neutral-100); color: var(--primary-600); border: 1px solid var(--neutral-200); }
.btn-secondary:hover { background: var(--neutral-200); }
.btn-ghost { background: transparent; color: var(--primary-600); border: none; }
.btn-ghost:hover { background: var(--primary-50); }
.btn:focus-visible { outline: 2px solid var(--primary-200); outline-offset: 2px; }
.btn-sm { padding: 5px 12px; font-size: 0.75rem; }

/* ---------- Sidebar / Navigation ---------- */
.rail {
  background: var(--neutral-50);
  border-right: 1px solid var(--neutral-200);
  padding: 16px 12px;
  display: flex;
  flex-direction: column;
  gap: 2px;
}
.nav-item {
  display: flex; align-items: center; justify-content: space-between;
  width: 100%;
  text-align: left;
  border: none;
  background: transparent;
  padding: 10px 12px;
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--neutral-600);
  cursor: pointer;
  border-radius: var(--radius-md);
  border-left: 2px solid transparent;
  min-height: 40px;
}
.nav-item:hover { background: var(--neutral-100); }
.nav-item.active {
  background: var(--primary-50);
  color: var(--primary-600);
  border-left: 2px solid var(--primary-600);
  font-weight: 600;
}
.nav-item .count {
  font-size: 0.75rem;
  color: var(--neutral-400);
  background: var(--neutral-100);
  padding: 1px 7px;
  border-radius: var(--radius-full);
}
.nav-item.active .count { color: var(--primary-600); background: var(--primary-100); }

.sub-nav {
  display: flex;
  flex-direction: column;
  gap: 2px;
  margin: 2px 0 8px 12px;
  padding-left: 10px;
  border-left: 1px solid var(--neutral-200);
}
.sub-nav .nav-item { padding: 8px 10px; font-weight: 400; min-height: 36px; }
.sub-nav .nav-item.active { font-weight: 600; }

/* ---------- Main content ---------- */
.main {
  padding: 28px 32px 60px;
  overflow-y: auto;
}
.view { display: none; }
.view.active { display: block; }

h1.page-title {
  font-size: 1.5rem;
  font-weight: 600;
  color: var(--neutral-900);
  margin: 0 0 4px;
  line-height: 1.25;
}
p.page-sub {
  font-size: 0.875rem;
  color: var(--neutral-600);
  margin: 0 0 24px;
}

.notebook-head-row {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
}

/* ---------- Cards ---------- */
.card {
  background: var(--neutral-0);
  border: 1px solid var(--neutral-200);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
  padding: 20px;
}

/* ---------- Home view ---------- */
.quick-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
  margin-bottom: 28px;
}
.quick-card {
  cursor: pointer;
  transition: box-shadow 150ms var(--ease), transform 150ms var(--ease);
}
.quick-card:hover { box-shadow: var(--shadow-md); transform: translateY(-1px); }
.quick-card h3 { font-size: 1.125rem; font-weight: 500; color: var(--neutral-900); margin: 0 0 4px; }
.quick-card p { font-size: 0.875rem; color: var(--neutral-600); margin: 0; }

.section-label { font-size: 0.75rem; font-weight: 600; color: var(--neutral-600); margin: 0 0 12px; }

.recent-list { display: flex; flex-direction: column; gap: 10px; }
.recent-row {
  display: flex; align-items: center; justify-content: space-between;
  background: var(--neutral-0);
  border: 1px solid var(--neutral-200);
  border-radius: var(--radius-md);
  padding: 12px 16px;
  cursor: pointer;
}
.recent-row:hover { background: var(--primary-50); }
.recent-row .rr-title { font-size: 0.875rem; font-weight: 500; color: var(--neutral-900); }
.recent-row .rr-meta { font-size: 0.75rem; color: var(--neutral-400); margin-top: 2px; }
.tag {
  font-size: 0.75rem; font-weight: 500;
  background: var(--neutral-100); color: var(--neutral-600);
  padding: 3px 10px; border-radius: var(--radius-full);
}

/* ---------- Notebooks view ---------- */
.compose-card { display: none; margin-bottom: 20px; }
.compose-card.open { display: block; }
.compose-card input, .compose-card textarea {
  width: 100%;
  font-family: inherit;
  font-size: 0.875rem;
  border: 1px solid var(--neutral-200);
  border-radius: var(--radius-md);
  padding: 10px 12px;
  margin-bottom: 10px;
  background: var(--neutral-100);
  color: var(--neutral-800);
}
.compose-card input:focus, .compose-card textarea:focus,
.about-edit textarea:focus {
  outline: 2px solid var(--primary-200);
  outline-offset: 1px;
  border-color: var(--primary-600);
  background: var(--neutral-0);
}
.compose-card textarea { min-height: 90px; resize: vertical; }
.compose-actions { display: flex; gap: 8px; justify-content: flex-end; }

.entry-row {
  display: grid;
  grid-template-columns: 1fr 190px;
  gap: 24px;
  padding: 20px 0;
  border-bottom: 1px solid var(--neutral-200);
}
.entry-row:last-child { border-bottom: none; }

.entry-meta { display: flex; align-items: center; gap: 8px; font-size: 0.75rem; color: var(--neutral-400); margin-bottom: 6px; }
.entry-title { font-size: 1.125rem; font-weight: 500; color: var(--neutral-900); margin: 0 0 8px; cursor: pointer; }
.entry-title:hover { color: var(--primary-600); }
.entry-body { font-size: 0.875rem; line-height: 1.6; color: var(--neutral-800); max-width: 62ch; }
.entry-body p { margin: 0 0 10px; }
.entry-body.collapsed p:nth-child(n+2) { display: none; }

.see-more { font-size: 0.875rem; font-weight: 600; color: var(--primary-600); background: none; border: none; cursor: pointer; padding: 0; }

.reference-card {
  border-left: 3px solid var(--primary-600);
  background: var(--primary-50);
  padding: 10px 14px;
  margin: 12px 0;
  font-size: 0.8125rem;
  color: var(--neutral-600);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
}
.reference-card .ref-title { font-weight: 600; color: var(--neutral-900); display: block; margin-bottom: 2px; }

.new-badge {
  font-size: 0.75rem; font-weight: 500;
  background: var(--accent-yellow-300); color: var(--neutral-900);
  padding: 2px 9px; border-radius: var(--radius-full);
}

.entry-margin { display: flex; flex-direction: column; gap: 10px; padding-top: 30px; }
.note { background: var(--neutral-0); border: 1px solid var(--neutral-200); border-radius: var(--radius-md); padding: 10px 12px; font-size: 0.8125rem; color: var(--neutral-800); }
.note-head { display: flex; align-items: center; gap: 6px; margin-bottom: 4px; }
.note .av { width: 18px; height: 18px; font-size: 0.5625rem; }
.note-name { font-weight: 600; font-size: 0.75rem; color: var(--neutral-900); }
.empty-margin { font-size: 0.75rem; color: var(--neutral-400); padding-top: 30px; }

.add-note-btn {
  align-self: flex-start;
  background: none; border: none; cursor: pointer; padding: 2px 0;
  font-size: 0.8125rem; font-weight: 500; color: var(--primary-600);
}
.add-note-btn:hover { text-decoration: underline; }
.note-compose {
  background: var(--neutral-0); border: 1px solid var(--primary-200);
  border-radius: var(--radius-md); padding: 10px;
}
.note-compose textarea {
  width: 100%; min-height: 56px; font-family: inherit; font-size: 0.8125rem;
  border: 1px solid var(--neutral-200); border-radius: var(--radius-sm);
  padding: 8px; background: var(--neutral-100); color: var(--neutral-800); resize: vertical;
}
.note-compose textarea:focus { outline: 2px solid var(--primary-200); outline-offset: 1px; border-color: var(--primary-600); background: var(--neutral-0); }

/* ---------- About view ---------- */
.about-body { font-size: 0.875rem; line-height: 1.7; color: var(--neutral-800); max-width: 62ch; }
.about-body p { margin: 0 0 12px; }
.about-edit textarea {
  width: 100%; min-height: 160px; font-family: inherit; font-size: 0.875rem; line-height: 1.6;
  border: 1px solid var(--neutral-200); border-radius: var(--radius-md);
  padding: 12px; background: var(--neutral-100); color: var(--neutral-800); resize: vertical;
}
.about-header { display: flex; align-items: center; justify-content: space-between; margin-bottom: 12px; }

/* ---------- Auth screen ---------- */
.auth-view {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 100vh;
  background: var(--neutral-50);
}
.auth-card {
  width: 340px;
  padding: 32px;
}
.auth-card .page-title { margin-bottom: 18px; }
#auth-form { display: flex; flex-direction: column; gap: 10px; }
#auth-form input {
  font-family: inherit;
  font-size: 0.875rem;
  border: 1px solid var(--neutral-200);
  border-radius: var(--radius-md);
  padding: 10px 12px;
  background: var(--neutral-100);
  color: var(--neutral-800);
}
#auth-form input:focus {
  outline: 2px solid var(--primary-200);
  outline-offset: 1px;
  border-color: var(--primary-600);
  background: var(--neutral-0);
}
.auth-error { font-size: 0.8125rem; color: var(--error-500); min-height: 1.2em; margin: 10px 0 0; }
.auth-toggle { display: block; margin-top: 6px; font-size: 0.8125rem; color: var(--primary-600); text-decoration: none; }
.auth-toggle:hover { text-decoration: underline; }

/* ---------- Invite ---------- */
.invite-wrap { position: relative; }

@media (max-width: 760px) {
  #app { grid-template-columns: 1fr; }
  .rail { flex-direction: column; }
  .entry-row { grid-template-columns: 1fr; }
  .quick-grid { grid-template-columns: 1fr; }
}