/* ============================================================
   StudyCircle — simple, clean styling
   ============================================================ */
:root {
  --primary: #4f46e5;
  --primary-dark: #4338ca;
  --danger: #dc2626;
  --success-bg: #dcfce7;
  --success-fg: #166534;
  --error-bg: #fee2e2;
  --error-fg: #991b1b;
  --text: #1f2937;
  --muted: #6b7280;
  --border: #e5e7eb;
  --bg: #f4f5f7;
  --card-bg: #ffffff;
  --radius: 10px;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: "Segoe UI", system-ui, -apple-system, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
}

a { color: var(--primary); text-decoration: none; }
a:hover { text-decoration: underline; }

/* ---------- Navbar ---------- */
.navbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  padding: 0.75rem 1.5rem;
  background: var(--primary);
  color: #fff;
  flex-wrap: wrap;
}
.brand {
  font-size: 1.25rem;
  font-weight: 700;
  color: #fff;
}
.brand:hover { text-decoration: none; opacity: 0.9; }
.nav-links {
  display: flex;
  align-items: center;
  gap: 1rem;
  flex-wrap: wrap;
}
.nav-links a { color: #e0e7ff; }
.nav-links a:hover { color: #fff; }
.nav-user { font-size: 0.9rem; color: #c7d2fe; }

/* ---------- Layout ---------- */
.container {
  max-width: 1000px;
  margin: 0 auto;
  padding: 1.5rem 1rem 3rem;
}

.page-head {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  flex-wrap: wrap;
  margin-bottom: 1rem;
}
.page-head h1 { margin: 0; }
.page-actions { display: flex; gap: 0.5rem; flex-wrap: wrap; }

.group-layout {
  display: grid;
  grid-template-columns: 1fr 260px;
  gap: 1.25rem;
  align-items: start;
}
@media (max-width: 760px) {
  .group-layout { grid-template-columns: 1fr; }
}

/* ---------- Cards ---------- */
.card {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.1rem 1.25rem;
}
.card:hover h3 a { text-decoration: underline; }
a.card { display: block; color: inherit; }
a.card:hover { text-decoration: none; box-shadow: 0 3px 12px rgba(0,0,0,0.07); }

.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(270px, 1fr));
  gap: 1rem;
}
.group-card h3 { margin: 0 0 0.25rem; }
.card-top {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 0.5rem;
  margin-bottom: 0.35rem;
}
.card-meta {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  margin-top: 0.75rem;
  font-size: 0.85rem;
  color: var(--muted);
}

.post-card h3 { margin: 0.25rem 0 0.5rem; }

/* ---------- Badges ---------- */
.badge {
  display: inline-block;
  padding: 0.15rem 0.6rem;
  border-radius: 999px;
  font-size: 0.75rem;
  font-weight: 600;
  white-space: nowrap;
}
.badge-article   { background: #e0e7ff; color: var(--primary-dark); }
.badge-question  { background: #fef3c7; color: #92400e; }
.badge-owner     { background: var(--primary); color: #fff; }
.badge-sm        { font-size: 0.68rem; padding: 0.05rem 0.5rem; }

/* ---------- Buttons ---------- */
.btn {
  display: inline-block;
  padding: 0.5rem 1rem;
  border: 1px solid var(--primary);
  background: #fff;
  color: var(--primary);
  border-radius: var(--radius);
  font-size: 0.95rem;
  cursor: pointer;
  text-align: center;
}
.btn:hover { background: #eef2ff; text-decoration: none; }
.btn-primary { background: var(--primary); color: #fff; }
.btn-primary:hover { background: var(--primary-dark); }
.btn-danger { background: var(--danger); border-color: var(--danger); color: #fff; }
.btn-danger:hover { background: #b91c1c; }
.btn-danger-outline { background: #fff; border-color: var(--danger); color: var(--danger); margin-top: 0.5rem; }
.btn-danger-outline:hover { background: #fef2f2; }
.btn-sm { padding: 0.3rem 0.75rem; font-size: 0.85rem; }
.btn-block { display: block; width: 100%; }
.btn[disabled] { opacity: 0.5; cursor: not-allowed; }

/* ---------- Forms ---------- */
label { display: block; margin-bottom: 1rem; font-weight: 600; }
input[type="text"], input[type="email"], input[type="password"], textarea {
  width: 100%;
  margin-top: 0.3rem;
  padding: 0.6rem 0.7rem;
  border: 1px solid var(--border);
  border-radius: 8px;
  font: inherit;
  background: #fff;
}
input:focus, textarea:focus {
  outline: 2px solid var(--primary);
  outline-offset: 1px;
}

.auth-card {
  max-width: 420px;
  margin: 2rem auto;
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem;
}
.auth-card.wide { max-width: 680px; }
.auth-card h1 { margin-top: 0; }

/* ---------- Alerts & empty states ---------- */
.alert {
  padding: 0.7rem 1rem;
  border-radius: 8px;
  margin-bottom: 1rem;
  font-size: 0.92rem;
}
.alert-success { background: var(--success-bg); color: var(--success-fg); }
.alert-error   { background: var(--error-bg); color: var(--error-fg); }

.empty-state {
  text-align: center;
  padding: 2.5rem 1rem;
  color: var(--muted);
  background: var(--card-bg);
  border: 1px dashed var(--border);
  border-radius: var(--radius);
}

/* ---------- Join panel & search panel ---------- */
.join-panel { margin-bottom: 1.25rem; }
.join-panel label { margin-bottom: 0.4rem; }
.join-row { display: flex; gap: 0.5rem; }
.join-row input { max-width: 220px; text-transform: uppercase; letter-spacing: 2px; }
.search-panel { margin-bottom: 1rem; }
.search-form { display: flex; gap: 0.5rem; flex-wrap: wrap; }
.search-form input { flex: 1 1 240px; margin-top: 0; }
.badge-member { background: #d1fae5; color: #065f46; }

/* ---------- Group header & share box ---------- */
.group-head {
  display: flex;
  justify-content: space-between;
  gap: 1.5rem;
  flex-wrap: wrap;
  margin-bottom: 1.25rem;
}
.group-head-main { flex: 1 1 320px; }
.group-head h1 { margin: 0 0 0.25rem; }
.share-box {
  flex: 0 1 300px;
  background: #eef2ff;
  border-radius: 8px;
  padding: 0.9rem 1rem;
}
.share-box h4 { margin: 0 0 0.3rem; }
.join-code {
  font-size: 1.5rem;
  font-weight: 800;
  letter-spacing: 5px;
  color: var(--primary-dark);
  margin: 0.2rem 0 0.6rem;
}
.share-row { display: flex; gap: 0.5rem; }
.share-row input { margin-top: 0; font-size: 0.78rem; color: var(--muted); }

/* ---------- Tabs ---------- */
.tabs {
  display: flex;
  gap: 0.25rem;
  margin-bottom: 1rem;
  border-bottom: 2px solid var(--border);
}
.tab {
  padding: 0.5rem 1rem;
  color: var(--muted);
  border-bottom: 3px solid transparent;
  margin-bottom: -2px;
  font-weight: 600;
}
.tab:hover { color: var(--primary); text-decoration: none; }
.tab.active { color: var(--primary); border-bottom-color: var(--primary); }

/* ---------- Sidebar ---------- */
.side-card { margin-bottom: 1rem; }
.side-card h4 { margin: 0 0 0.6rem; }
.member-list { list-style: none; margin: 0; padding: 0; }
.member-list li { padding: 0.3rem 0; border-bottom: 1px solid var(--border); }
.member-list li:last-child { border-bottom: none; }
.inline-form { margin: 0 0 0.5rem; }
.inline-form:last-child { margin-bottom: 0; }

/* ---------- Post view ---------- */
.post-view { margin-bottom: 1.5rem; }
.post-view h1 { margin: 0.3rem 0 0.8rem; }
.post-content { font-size: 1.02rem; white-space: pre-wrap; }
.post-footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  margin-top: 1rem;
  flex-wrap: wrap;
}
.post-footer .card-meta { margin-top: 0; }

/* ---------- Attachments ---------- */
.attachments { margin-top: 1rem; display: flex; flex-wrap: wrap; gap: 0.75rem; }
.attach-thumb {
  display: block;
  width: 150px;
  height: 110px;
  border: 1px solid var(--border);
  border-radius: 8px;
  overflow: hidden;
  background: #f9fafb;
}
.attach-thumb img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
  transition: transform 0.15s ease;
}
.attach-thumb:hover img { transform: scale(1.05); }

.pdf-chip {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.6rem 0.9rem;
  background: #fffdf5;
  flex: 1 1 260px;
  max-width: 420px;
}
.pdf-icon { font-size: 1.6rem; }
.pdf-info { display: flex; flex-direction: column; flex: 1; min-width: 0; }
.pdf-name {
  font-weight: 600;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  max-width: 180px;
}

/* ---------- PDF viewer page ---------- */
.pdf-viewer {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  background: #525659;
  margin-bottom: 0.75rem;
}
.pdf-viewer iframe {
  display: block;
  width: 100%;
  height: 78vh;
  border: 0;
}
.pdf-title { font-size: 1.3rem; margin: 0; word-break: break-all; }

/* ---------- Storage quota ---------- */
.quota-line { display: flex; align-items: center; gap: 0.6rem; flex-wrap: wrap; }
.quota-bar {
  display: inline-block;
  width: 140px;
  height: 8px;
  border-radius: 999px;
  background: var(--border);
  overflow: hidden;
  vertical-align: middle;
}
.quota-bar span { display: block; height: 100%; background: var(--primary); }
.file-hint { margin: -0.6rem 0 0.8rem; }
.replies-heading { font-size: 1.2rem; margin: 1.5rem 0 0.75rem; }
.reply-card { margin-bottom: 0.75rem; padding: 0.85rem 1.1rem; }
.reply-form-card textarea { margin-bottom: 0.75rem; }
.reply-form-card h3 { margin-top: 0; }

/* ---------- Footer & misc ---------- */
.footer {
  text-align: center;
  padding: 1.2rem;
  color: var(--muted);
  font-size: 0.85rem;
  border-top: 1px solid var(--border);
  background: #fff;
}
.muted { color: var(--muted); }
.small { font-size: 0.85rem; }