@import url('https://fonts.googleapis.com/css2?family=Cinzel:wght@400;600;700&family=Inter:wght@300;400;500;600&display=swap');

:root {
  --bg: #0a0806;
  --bg-card: rgba(20, 17, 12, 0.85);
  --bg-card-hover: rgba(30, 25, 18, 0.95);
  --bg-input: rgba(30, 25, 18, 0.9);
  --gold: #f0d890;
  --gold-dim: #a08960;
  --gold-bright: #f5e6b8;
  --amber: #c9a84c;
  --text: #e8d5b0;
  --text-dim: #8a7a60;
  --text-bright: #f5eed8;
  --accent: #8bc34a;
  --accent-dim: rgba(139, 195, 74, 0.15);
  --danger: #e57373;
  --border: rgba(160, 137, 96, 0.2);
  --border-bright: rgba(200, 168, 76, 0.4);
  --radius: 8px;
  --radius-lg: 14px;
  --shadow: 0 4px 24px rgba(0,0,0,0.5);
  --transition: 0.25s cubic-bezier(.25,.46,.45,.94);
}

* { margin: 0; padding: 0; box-sizing: border-box; }

body {
  background: var(--bg);
  color: var(--text);
  font-family: 'Inter', sans-serif;
  min-height: 100vh;
  overflow-x: hidden;
  line-height: 1.6;
}

/* ── Scrollbar ── */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: rgba(10,8,6,.8); }
::-webkit-scrollbar-thumb { background: rgba(160,137,96,.4); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: rgba(200,168,76,.5); }

/* ── Background mist ── */
.mist {
  position: fixed; inset: 0; z-index: 0; pointer-events: none;
  background:
    radial-gradient(ellipse 80% 40% at 20% 80%, rgba(42,35,25,.6) 0%, transparent 70%),
    radial-gradient(ellipse 60% 50% at 80% 20%, rgba(58,48,30,.4) 0%, transparent 60%);
}

/* ── Layout ── */
.app-shell {
  position: relative; z-index: 1;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}

.app-shell.wide { max-width: 1400px; }

/* ── Top Nav ── */
.top-nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 20px 0;
  border-bottom: 1px solid var(--border);
  margin-bottom: 30px;
  flex-wrap: wrap;
  gap: 12px;
}

.top-nav .brand {
  font-family: 'Cinzel', serif;
  font-size: 1.1rem;
  font-weight: 700;
  background: linear-gradient(135deg, #f0d890, #c9a84c);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  text-decoration: none;
  letter-spacing: 0.1em;
}

.top-nav .nav-links {
  display: flex;
  align-items: center;
  gap: 16px;
}

.top-nav .nav-links a {
  color: var(--gold-dim);
  text-decoration: none;
  font-size: 0.82rem;
  letter-spacing: 0.05em;
  transition: color var(--transition);
}
.top-nav .nav-links a:hover { color: var(--gold); }

.nav-avatar {
  width: 32px; height: 32px;
  border-radius: 50%;
  border: 1.5px solid var(--amber);
  object-fit: cover;
  cursor: pointer;
}

.notif-badge {
  position: relative;
  display: inline-flex;
}
.notif-badge .count {
  position: absolute;
  top: -5px; right: -8px;
  background: var(--danger);
  color: #fff;
  font-size: 0.6rem;
  font-weight: 700;
  width: 16px; height: 16px;
  border-radius: 50%;
  display: flex; align-items: center; justify-content: center;
}

/* ── Buttons ── */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 18px;
  border: 1px solid var(--border-bright);
  border-radius: var(--radius);
  background: transparent;
  color: var(--gold);
  font-family: 'Inter', sans-serif;
  font-size: 0.82rem;
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition);
  letter-spacing: 0.03em;
  text-decoration: none;
}
.btn:hover {
  background: rgba(200,168,76,0.1);
  border-color: var(--gold);
  color: var(--gold-bright);
}
.btn-primary {
  background: linear-gradient(135deg, rgba(200,168,76,0.2), rgba(139,195,74,0.15));
  border-color: var(--amber);
}
.btn-primary:hover {
  background: linear-gradient(135deg, rgba(200,168,76,0.35), rgba(139,195,74,0.25));
}
.btn-danger { border-color: var(--danger); color: var(--danger); }
.btn-danger:hover { background: rgba(229,115,115,0.1); }
.btn-sm { padding: 5px 12px; font-size: 0.75rem; }
.btn:disabled { opacity: 0.4; cursor: not-allowed; }

/* ── Form controls ── */
.form-group { margin-bottom: 16px; }
.form-group label {
  display: block;
  font-size: 0.75rem;
  color: var(--gold-dim);
  letter-spacing: 0.06em;
  margin-bottom: 6px;
  font-weight: 500;
}

input[type="text"], input[type="email"], input[type="password"],
input[type="url"], input[type="search"], textarea, select {
  width: 100%;
  padding: 10px 14px;
  background: var(--bg-input);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  color: var(--text);
  font-family: 'Inter', sans-serif;
  font-size: 0.88rem;
  transition: border-color var(--transition);
  outline: none;
}
input:focus, textarea:focus, select:focus {
  border-color: var(--amber);
}
textarea { resize: vertical; min-height: 80px; }
select { cursor: pointer; }

/* ── Cards ── */
.card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 24px;
  transition: all var(--transition);
}
.card:hover {
  background: var(--bg-card-hover);
  border-color: var(--border-bright);
}

/* ── Modal ── */
.modal-overlay {
  display: none;
  position: fixed; inset: 0;
  background: rgba(0,0,0,0.75);
  z-index: 1000;
  align-items: center;
  justify-content: center;
  padding: 20px;
}
.modal-overlay.active { display: flex; }
.modal {
  background: #151210;
  border: 1px solid var(--border-bright);
  border-radius: var(--radius-lg);
  padding: 32px;
  max-width: 480px;
  width: 100%;
  max-height: 90vh;
  overflow-y: auto;
  box-shadow: 0 8px 60px rgba(0,0,0,0.7);
}
.modal h2 {
  font-family: 'Cinzel', serif;
  font-size: 1.15rem;
  color: var(--gold);
  margin-bottom: 20px;
  letter-spacing: 0.08em;
}
.modal-close {
  float: right;
  background: none; border: none;
  color: var(--text-dim);
  font-size: 1.2rem;
  cursor: pointer;
}
.modal-close:hover { color: var(--text); }

/* ── Auth page ── */
.auth-container {
  max-width: 420px;
  margin: 80px auto;
}
.auth-container h1 {
  font-family: 'Cinzel', serif;
  font-size: 1.5rem;
  background: linear-gradient(135deg, #f0d890, #c9a84c);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  text-align: center;
  margin-bottom: 8px;
  letter-spacing: 0.12em;
}
.auth-container .auth-sub {
  text-align: center;
  color: var(--text-dim);
  font-size: 0.82rem;
  margin-bottom: 28px;
}
.auth-toggle {
  text-align: center;
  margin-top: 20px;
  font-size: 0.8rem;
  color: var(--text-dim);
}
.auth-toggle a {
  color: var(--amber);
  cursor: pointer;
  text-decoration: underline;
}
.auth-error {
  background: rgba(229,115,115,0.1);
  border: 1px solid rgba(229,115,115,0.3);
  color: var(--danger);
  padding: 8px 14px;
  border-radius: var(--radius);
  font-size: 0.8rem;
  margin-bottom: 14px;
  display: none;
}

/* ── Papers grid ── */
.papers-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 24px;
  flex-wrap: wrap;
  gap: 12px;
}
.papers-header h1 {
  font-family: 'Cinzel', serif;
  font-size: 1.3rem;
  color: var(--gold);
  letter-spacing: 0.08em;
}

.search-bar {
  display: flex;
  gap: 10px;
  margin-bottom: 24px;
  flex-wrap: wrap;
}
.search-bar input {
  flex: 1;
  min-width: 200px;
}
.search-bar select {
  width: 160px;
  flex-shrink: 0;
}

.papers-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 20px;
  margin-bottom: 40px;
}

.paper-card {
  cursor: pointer;
}
.paper-card .paper-title {
  font-family: 'Cinzel', serif;
  font-size: 0.95rem;
  color: var(--gold);
  margin-bottom: 6px;
  letter-spacing: 0.04em;
}
.paper-card .paper-meta {
  font-size: 0.75rem;
  color: var(--text-dim);
  margin-bottom: 10px;
  display: flex;
  gap: 14px;
  flex-wrap: wrap;
}
.paper-card .paper-desc {
  font-size: 0.82rem;
  color: var(--text);
  line-height: 1.5;
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}
.paper-card .paper-tags {
  margin-top: 10px;
  display: flex;
  gap: 6px;
  flex-wrap: wrap;
}
.tag {
  padding: 2px 10px;
  background: var(--accent-dim);
  border: 1px solid rgba(139,195,74,0.2);
  border-radius: 20px;
  font-size: 0.68rem;
  color: var(--accent);
  letter-spacing: 0.04em;
}

/* ── Paper detail layout ── */
.paper-detail-layout {
  display: grid;
  grid-template-columns: 1fr 400px;
  gap: 24px;
  margin-bottom: 40px;
}
@media (max-width: 900px) {
  .paper-detail-layout {
    grid-template-columns: 1fr;
  }
}

.pdf-viewer-wrap {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  min-height: 600px;
}
.pdf-viewer-wrap iframe {
  width: 100%;
  height: 700px;
  border: none;
}

.comments-panel {
  display: flex;
  flex-direction: column;
  max-height: 800px;
}
.comments-list {
  flex: 1;
  overflow-y: auto;
  padding-right: 4px;
  margin-bottom: 16px;
}

/* ── Single comment ── */
.comment {
  padding: 14px;
  border-bottom: 1px solid var(--border);
}
.comment:last-child { border-bottom: none; }
.comment-header {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 6px;
}
.comment-avatar {
  width: 28px; height: 28px;
  border-radius: 50%;
  object-fit: cover;
  border: 1px solid var(--border-bright);
}
.comment-author {
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--gold);
}
.comment-time {
  font-size: 0.68rem;
  color: var(--text-dim);
  margin-left: auto;
}
.comment-body {
  font-size: 0.84rem;
  color: var(--text);
  line-height: 1.55;
  word-break: break-word;
}
.comment-body .mention {
  color: var(--accent);
  font-weight: 500;
  cursor: pointer;
}
.comment-actions {
  margin-top: 6px;
  display: flex;
  gap: 12px;
}
.comment-actions button {
  background: none; border: none;
  color: var(--text-dim);
  font-size: 0.72rem;
  cursor: pointer;
  font-family: 'Inter', sans-serif;
}
.comment-actions button:hover { color: var(--gold); }

.reply-indent { margin-left: 28px; border-left: 2px solid var(--border); }

/* ── Comment input ── */
.comment-input-wrap {
  border-top: 1px solid var(--border);
  padding-top: 14px;
}
.comment-input-wrap textarea {
  min-height: 60px;
  margin-bottom: 8px;
}
.mention-suggestions {
  display: none;
  position: absolute;
  background: #1a1714;
  border: 1px solid var(--border-bright);
  border-radius: var(--radius);
  max-height: 150px;
  overflow-y: auto;
  z-index: 500;
  min-width: 180px;
}
.mention-suggestions.active { display: block; }
.mention-suggestion {
  padding: 8px 12px;
  font-size: 0.8rem;
  color: var(--text);
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 8px;
}
.mention-suggestion:hover { background: rgba(200,168,76,0.1); }
.mention-suggestion img {
  width: 22px; height: 22px;
  border-radius: 50%;
  object-fit: cover;
}

/* ── Profile page ── */
.profile-layout {
  display: grid;
  grid-template-columns: 280px 1fr;
  gap: 24px;
  margin-bottom: 40px;
}
@media (max-width: 800px) {
  .profile-layout { grid-template-columns: 1fr; }
}

.profile-sidebar { text-align: center; }
.profile-avatar-wrap {
  position: relative;
  width: 120px; height: 120px;
  margin: 0 auto 16px;
}
.profile-avatar-wrap img {
  width: 100%; height: 100%;
  border-radius: 50%;
  object-fit: cover;
  border: 2px solid var(--amber);
}
.profile-avatar-wrap .avatar-edit {
  position: absolute;
  bottom: 4px; right: 4px;
  width: 30px; height: 30px;
  border-radius: 50%;
  background: var(--bg-card);
  border: 1px solid var(--amber);
  color: var(--gold);
  font-size: 0.75rem;
  display: flex; align-items: center; justify-content: center;
  cursor: pointer;
}
.profile-name {
  font-family: 'Cinzel', serif;
  font-size: 1.1rem;
  color: var(--gold);
  margin-bottom: 4px;
}
.profile-email {
  font-size: 0.75rem;
  color: var(--text-dim);
  margin-bottom: 16px;
}
.profile-stat {
  display: flex;
  justify-content: center;
  gap: 20px;
  margin-bottom: 16px;
}
.profile-stat div {
  text-align: center;
}
.profile-stat .stat-num {
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--gold);
}
.profile-stat .stat-label {
  font-size: 0.68rem;
  color: var(--text-dim);
  letter-spacing: 0.05em;
}

.profile-content .tabs {
  display: flex;
  border-bottom: 1px solid var(--border);
  margin-bottom: 20px;
  gap: 4px;
}
.profile-content .tab {
  padding: 10px 18px;
  font-size: 0.82rem;
  color: var(--text-dim);
  cursor: pointer;
  border-bottom: 2px solid transparent;
  transition: all var(--transition);
  background: none;
  border-top: none; border-left: none; border-right: none;
  font-family: 'Inter', sans-serif;
}
.profile-content .tab.active {
  color: var(--gold);
  border-bottom-color: var(--amber);
}
.profile-content .tab:hover { color: var(--gold); }

.tab-pane { display: none; }
.tab-pane.active { display: block; }

/* ── Notifications ── */
.notif-item {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  padding: 14px;
  border-bottom: 1px solid var(--border);
  transition: background var(--transition);
  cursor: pointer;
}
.notif-item:hover { background: rgba(200,168,76,0.05); }
.notif-item.unread { background: rgba(139,195,74,0.05); }
.notif-item .notif-icon {
  width: 32px; height: 32px;
  border-radius: 50%;
  background: var(--accent-dim);
  display: flex; align-items: center; justify-content: center;
  font-size: 0.85rem;
  flex-shrink: 0;
}
.notif-item .notif-text {
  font-size: 0.82rem;
  color: var(--text);
  line-height: 1.45;
}
.notif-item .notif-text strong { color: var(--gold); }
.notif-item .notif-time {
  font-size: 0.68rem;
  color: var(--text-dim);
  margin-top: 4px;
}
.notif-dot {
  width: 8px; height: 8px;
  border-radius: 50%;
  background: var(--accent);
  flex-shrink: 0;
  margin-top: 6px;
}

/* ── Settings form ── */
.settings-section {
  margin-bottom: 28px;
}
.settings-section h3 {
  font-size: 0.9rem;
  color: var(--gold);
  margin-bottom: 14px;
  letter-spacing: 0.06em;
}
.toggle-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 10px 0;
  border-bottom: 1px solid var(--border);
}
.toggle-row .toggle-label {
  font-size: 0.82rem;
  color: var(--text);
}
.toggle-row .toggle-desc {
  font-size: 0.72rem;
  color: var(--text-dim);
}
.toggle-switch {
  position: relative;
  width: 42px; height: 22px;
}
.toggle-switch input { opacity: 0; width: 0; height: 0; }
.toggle-switch .slider {
  position: absolute; inset: 0;
  background: rgba(160,137,96,0.2);
  border-radius: 22px;
  cursor: pointer;
  transition: background var(--transition);
}
.toggle-switch .slider::before {
  content: '';
  position: absolute;
  left: 3px; bottom: 3px;
  width: 16px; height: 16px;
  background: var(--text-dim);
  border-radius: 50%;
  transition: all var(--transition);
}
.toggle-switch input:checked + .slider {
  background: rgba(139,195,74,0.3);
}
.toggle-switch input:checked + .slider::before {
  transform: translateX(20px);
  background: var(--accent);
}

/* ── Loading / empty states ── */
.loading-spinner {
  display: flex;
  justify-content: center;
  padding: 40px;
}
.loading-spinner::after {
  content: '';
  width: 28px; height: 28px;
  border: 2px solid var(--border);
  border-top-color: var(--amber);
  border-radius: 50%;
  animation: spin 0.7s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }

.empty-state {
  text-align: center;
  padding: 40px 20px;
  color: var(--text-dim);
  font-size: 0.88rem;
}

/* ── Pagination ── */
.pagination {
  display: flex;
  justify-content: center;
  gap: 8px;
  margin: 20px 0;
}

/* ── Upload progress ── */
.upload-progress {
  height: 4px;
  background: var(--border);
  border-radius: 2px;
  margin-top: 10px;
  overflow: hidden;
  display: none;
}
.upload-progress .bar {
  height: 100%;
  background: linear-gradient(90deg, var(--amber), var(--accent));
  width: 0%;
  transition: width 0.3s;
  border-radius: 2px;
}

/* ── Toast notifications ── */
.toast-container {
  position: fixed;
  bottom: 24px;
  right: 24px;
  z-index: 2000;
  display: flex;
  flex-direction: column;
  gap: 8px;
}
.toast {
  padding: 12px 20px;
  background: #1a1714;
  border: 1px solid var(--border-bright);
  border-radius: var(--radius);
  color: var(--text);
  font-size: 0.82rem;
  box-shadow: var(--shadow);
  animation: toastIn 0.3s ease;
  max-width: 360px;
}
.toast.error { border-color: var(--danger); }
.toast.success { border-color: var(--accent); }
@keyframes toastIn {
  from { opacity: 0; transform: translateY(12px); }
  to { opacity: 1; transform: translateY(0); }
}

/* ── Google Sign-In Button ── */
.google-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  width: 100%;
  padding: 10px 18px;
  border: 1px solid var(--border-bright);
  border-radius: var(--radius);
  background: rgba(255,255,255,0.05);
  color: var(--text);
  font-family: 'Inter', sans-serif;
  font-size: 0.88rem;
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition);
  margin-bottom: 18px;
}
.google-btn:hover {
  background: rgba(255,255,255,0.1);
  border-color: var(--gold);
}
.google-btn svg { flex-shrink: 0; }

.auth-divider {
  display: flex;
  align-items: center;
  gap: 14px;
  margin-bottom: 18px;
  color: var(--text-dim);
  font-size: 0.75rem;
}
.auth-divider::before, .auth-divider::after {
  content: '';
  flex: 1;
  height: 1px;
  background: var(--border);
}

/* ── Sharing / Visibility Modal ── */
.share-modal-content {
  text-align: center;
}
.share-options {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin: 20px 0;
}
.share-option {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 14px 18px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--bg-card);
  cursor: pointer;
  transition: all var(--transition);
  text-align: left;
}
.share-option:hover, .share-option.selected {
  border-color: var(--amber);
  background: rgba(200,168,76,0.1);
}
.share-option .share-icon {
  font-size: 1.3rem;
  width: 36px;
  text-align: center;
  flex-shrink: 0;
}
.share-option .share-label {
  font-size: 0.88rem;
  color: var(--gold);
  font-weight: 500;
}
.share-option .share-desc {
  font-size: 0.72rem;
  color: var(--text-dim);
  margin-top: 2px;
}

/* ── Friend picker checkboxes ── */
.friend-picker {
  max-height: 250px;
  overflow-y: auto;
  margin: 14px 0;
  border: 1px solid var(--border);
  border-radius: var(--radius);
}
.friend-picker-item {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 10px 14px;
  border-bottom: 1px solid var(--border);
  cursor: pointer;
  transition: background var(--transition);
}
.friend-picker-item:last-child { border-bottom: none; }
.friend-picker-item:hover { background: rgba(200,168,76,0.05); }
.friend-picker-item input[type="checkbox"] {
  width: 16px;
  height: 16px;
  accent-color: var(--amber);
}
.friend-picker-item .friend-name {
  font-size: 0.85rem;
  color: var(--text);
}
.friend-picker-empty {
  padding: 20px;
  text-align: center;
  color: var(--text-dim);
  font-size: 0.82rem;
}

/* ── Friends tab / management ── */
.friend-group-card {
  padding: 16px;
  border-bottom: 1px solid var(--border);
}
.friend-group-card:last-child { border-bottom: none; }
.friend-group-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 8px;
}
.friend-group-name {
  font-family: 'Cinzel', serif;
  font-size: 0.92rem;
  color: var(--gold);
}
.friend-group-members {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-top: 8px;
}
.friend-chip {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 12px;
  background: var(--accent-dim);
  border: 1px solid rgba(139,195,74,0.2);
  border-radius: 20px;
  font-size: 0.75rem;
  color: var(--accent);
}
.friend-chip .remove-friend {
  cursor: pointer;
  font-size: 0.85rem;
  opacity: 0.6;
}
.friend-chip .remove-friend:hover { opacity: 1; }

.add-friend-row {
  display: flex;
  gap: 8px;
  margin-top: 10px;
}
.add-friend-row input { flex: 1; }

.visibility-badge {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 2px 8px;
  border-radius: 12px;
  font-size: 0.65rem;
  font-weight: 500;
  letter-spacing: 0.03em;
}
.visibility-badge.public {
  background: rgba(139,195,74,0.15);
  color: var(--accent);
  border: 1px solid rgba(139,195,74,0.25);
}
.visibility-badge.friends {
  background: rgba(100,149,237,0.15);
  color: #6495ed;
  border: 1px solid rgba(100,149,237,0.25);
}
.visibility-badge.private {
  background: rgba(200,168,76,0.15);
  color: var(--amber);
  border: 1px solid rgba(200,168,76,0.25);
}

/* ── Responsive ── */
@media (max-width: 600px) {
  .papers-grid { grid-template-columns: 1fr; }
  .paper-detail-layout { grid-template-columns: 1fr; }
  .profile-layout { grid-template-columns: 1fr; }
  .top-nav { padding: 14px 0; }
  .modal { padding: 20px; }
}