:root {
  --ink: #1a1a1a;
  --muted: #767676;
  --border: #e5e5e5;
  --bg: #ffffff;
  --bg-soft: #fafafa;
  --accent: #1a1a1a;
  --danger: #c0392b;
  --radius: 10px;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  color: var(--ink);
  background: var(--bg);
  line-height: 1.5;
}

a { color: inherit; text-decoration: none; }

.container {
  max-width: 880px;
  margin: 0 auto;
  padding: 32px 20px 80px;
}

/* ---- topbar ---- */
.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 24px;
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  background: var(--bg);
  z-index: 10;
}
.brand {
  font-weight: 700;
  font-size: 1.1rem;
  letter-spacing: -0.02em;
}
.topbar nav { display: flex; align-items: center; gap: 14px; }
.user-chip {
  font-size: 0.85rem;
  color: var(--muted);
  padding: 6px 10px;
  border: 1px solid var(--border);
  border-radius: 20px;
}
.link-btn, .link-btn-nav {
  background: none;
  border: none;
  cursor: pointer;
  font-size: 0.9rem;
  color: var(--muted);
  padding: 0;
}
.link-btn:hover, .link-btn-nav:hover { color: var(--ink); }

/* ---- buttons ---- */
.btn {
  display: inline-block;
  padding: 9px 16px;
  border-radius: 8px;
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  border: 1px solid transparent;
}
.btn-primary { background: var(--ink); color: #fff; border-color: var(--ink); }
.btn-primary:hover { opacity: 0.85; }
.btn-outline { background: #fff; color: var(--ink); border-color: var(--border); }
.btn-outline:hover { border-color: var(--ink); }
.btn-danger { background: #fff; color: var(--danger); border-color: var(--danger); margin-top: 24px; }
.btn-danger:hover { background: var(--danger); color: #fff; }

/* ---- page ---- */
.page-title { font-size: 1.4rem; margin-bottom: 24px; letter-spacing: -0.02em; }
.empty-state { color: var(--muted); }

/* ---- post grid / card ---- */
.post-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 20px;
}
.post-card {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  transition: box-shadow 0.15s, transform 0.15s;
  display: block;
}
.post-card:hover { box-shadow: 0 4px 16px rgba(0,0,0,0.06); transform: translateY(-2px); }
.thumb-wrap { aspect-ratio: 16/10; background: var(--bg-soft); overflow: hidden; }
.thumb-wrap img { width: 100%; height: 100%; object-fit: cover; display: block; }
.thumb-placeholder {
  width: 100%; height: 100%;
  display: flex; align-items: center; justify-content: center;
  font-size: 2rem; color: var(--border);
}
.post-card-body { padding: 14px; }
.post-card-body h3 { margin: 0 0 6px; font-size: 1rem; }
.post-desc { color: var(--muted); font-size: 0.85rem; margin: 0 0 8px; }
.post-meta { color: var(--muted); font-size: 0.78rem; }

/* ---- post detail ---- */
.post-hero { width: 100%; max-height: 360px; object-fit: cover; border-radius: var(--radius); margin-bottom: 20px; }
.post-detail h1 { margin: 0 0 4px; font-size: 1.6rem; letter-spacing: -0.02em; }
.post-desc-full { color: var(--muted); margin-top: 12px; }

.materials { margin-top: 28px; display: flex; flex-direction: column; gap: 18px; }
.material-item {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px;
}
.material-item h4 { margin: 0 0 8px; font-size: 0.9rem; color: var(--muted); }
.material-text { margin: 0; white-space: pre-wrap; }
.material-item img { max-width: 100%; border-radius: 6px; display: block; }
.pdf-chip, .link-chip {
  display: inline-block;
  padding: 8px 12px;
  border: 1px solid var(--border);
  border-radius: 8px;
  font-size: 0.88rem;
  word-break: break-all;
}
.pdf-chip:hover, .link-chip:hover { border-color: var(--ink); }

/* ---- auth ---- */
.auth-box, .form-box {
  max-width: 420px;
  margin: 40px auto;
}
.form-box { max-width: 640px; }
.auth-box h1, .form-box h1 { font-size: 1.4rem; margin-bottom: 20px; }

form { display: flex; flex-direction: column; gap: 4px; }
label { font-size: 0.82rem; color: var(--muted); margin-top: 12px; }
input[type="text"], input[type="password"], input[type="file"], textarea, select {
  padding: 10px 12px;
  border: 1px solid var(--border);
  border-radius: 8px;
  font-size: 0.95rem;
  font-family: inherit;
  width: 100%;
}
textarea { resize: vertical; }
form .btn { margin-top: 18px; align-self: flex-start; }

.error-msg {
  background: #fdecea;
  color: var(--danger);
  padding: 10px 12px;
  border-radius: 8px;
  font-size: 0.88rem;
}
.success-msg {
  background: #e6f4ea;
  color: #1e7e34;
  padding: 10px 12px;
  border-radius: 8px;
  font-size: 0.88rem;
}
.auth-switch { margin-top: 16px; font-size: 0.88rem; color: var(--muted); }
.auth-switch a { text-decoration: underline; }

hr { border: none; border-top: 1px solid var(--border); margin: 24px 0; }
.hint { color: var(--muted); font-size: 0.85rem; margin-top: -4px; }

/* ---- material rows in form ---- */
.material-row {
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 14px;
  margin-bottom: 12px;
}
.material-row-head {
  display: flex;
  gap: 10px;
  align-items: center;
  margin-bottom: 10px;
}
.material-row-head select { width: auto; flex: 0 0 120px; }
.material-row-head .matLabel { flex: 1; }
.remove-material { color: var(--danger); white-space: nowrap; }

.loading-state { color: var(--muted); text-align: center; padding: 40px 0; }

.pin-badge {
  position: absolute;
  top: 8px;
  left: 8px;
  background: #1a1a1a;
  color: #fff;
  font-size: 0.72rem;
  font-weight: 600;
  padding: 3px 8px;
  border-radius: 20px;
  z-index: 1;
}
.thumb-wrap { position: relative; }
.pin-badge-detail { position: static; display: inline-block; margin-bottom: 12px; }
.post-actions { display: flex; gap: 10px; margin-top: 24px; }
.post-actions .btn-danger { margin-top: 0; }

/* ---- admin page ---- */
.admin-section { margin-bottom: 40px; }
.admin-section h2 { font-size: 1.1rem; margin-bottom: 14px; }
.admin-table { width: 100%; border-collapse: collapse; }
.admin-table th, .admin-table td {
  text-align: left;
  padding: 10px 12px;
  border-bottom: 1px solid var(--border);
  font-size: 0.88rem;
}
.admin-table th { color: var(--muted); font-weight: 600; font-size: 0.78rem; text-transform: uppercase; }
.admin-table .btn { padding: 5px 10px; font-size: 0.8rem; }
.admin-tabs { display: flex; gap: 8px; margin-bottom: 24px; border-bottom: 1px solid var(--border); }
.admin-tab {
  padding: 10px 4px;
  cursor: pointer;
  color: var(--muted);
  border-bottom: 2px solid transparent;
  font-size: 0.9rem;
  font-weight: 600;
}
.admin-tab.active { color: var(--ink); border-bottom-color: var(--ink); }
.admin-panel { display: none; }
.admin-panel.active { display: block; }
.badge-admin { font-size: 0.72rem; background: #fff3cd; color: #856404; padding: 2px 8px; border-radius: 20px; margin-left: 6px; }