/* ── Reset & Variables ────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --bg-primary:    #0d1117;
  --bg-secondary:  #161b22;
  --bg-tertiary:   #1c2128;
  --bg-card:       #21262d;
  --border:        #30363d;
  --border-hover:  #484f58;
  --accent:        #58a6ff;
  --accent-hover:  #79b8ff;
  --accent-dim:    rgba(88,166,255,.12);
  --success:       #3fb950;
  --warning:       #d29922;
  --danger:        #f85149;
  --danger-dim:    rgba(248,81,73,.12);
  --text-primary:  #e6edf3;
  --text-secondary:#8b949e;
  --text-muted:    #6e7681;
  --deleted:       #f85149;
  --font-mono:     'JetBrains Mono', 'Fira Code', monospace;
  --font-sans:     'Inter', 'Segoe UI', system-ui, sans-serif;
  --radius:        8px;
  --radius-sm:     4px;
  --shadow:        0 4px 24px rgba(0,0,0,.4);
  --shadow-sm:     0 2px 8px rgba(0,0,0,.3);
  --transition:    all 0.2s ease;
}

html { font-size: 15px; scroll-behavior: smooth; }

body {
  font-family: var(--font-sans);
  background:  var(--bg-primary);
  color:       var(--text-primary);
  min-height:  100vh;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

/* ── Typography ────────────────────────────────────────────── */
h1,h2,h3,h4 { font-weight: 600; line-height: 1.3; }
a { color: var(--accent); text-decoration: none; }
a:hover { color: var(--accent-hover); }

/* ── Utilities ─────────────────────────────────────────────── */
.hidden  { display: none !important; }
.sr-only { position:absolute; width:1px; height:1px; overflow:hidden; clip:rect(0,0,0,0); }

/* ── Buttons ───────────────────────────────────────────────── */
.btn {
  display:         inline-flex;
  align-items:     center;
  gap:             6px;
  padding:         8px 16px;
  border:          1px solid transparent;
  border-radius:   var(--radius-sm);
  font-size:       .875rem;
  font-weight:     500;
  cursor:          pointer;
  transition:      var(--transition);
  white-space:     nowrap;
  user-select:     none;
}
.btn:disabled { opacity: .5; cursor: not-allowed; }
.btn-primary  { background: var(--accent); color: #0d1117; border-color: var(--accent); }
.btn-primary:hover:not(:disabled) { background: var(--accent-hover); border-color: var(--accent-hover); }
.btn-secondary{ background: transparent; color: var(--text-primary); border-color: var(--border); }
.btn-secondary:hover:not(:disabled) { background: var(--bg-tertiary); border-color: var(--border-hover); }
.btn-danger   { background: var(--danger-dim); color: var(--danger); border-color: var(--danger); }
.btn-danger:hover:not(:disabled) { background: var(--danger); color: #fff; }
.btn-success  { background: transparent; color: var(--success); border-color: var(--success); }
.btn-success:hover:not(:disabled) { background: var(--success); color: #0d1117; }
.btn-sm { padding: 4px 10px; font-size: .8rem; }
.btn-icon { padding: 6px; }

/* ── Form Elements ─────────────────────────────────────────── */
.form-group       { display: flex; flex-direction: column; gap: 6px; }
.form-group label { font-size: .875rem; font-weight: 500; color: var(--text-secondary); }

input[type="text"],
input[type="email"],
input[type="password"],
textarea,
select {
  width:        100%;
  padding:      10px 12px;
  background:   var(--bg-tertiary);
  border:       1px solid var(--border);
  border-radius: var(--radius-sm);
  color:        var(--text-primary);
  font-size:    .9375rem;
  font-family:  var(--font-sans);
  outline:      none;
  transition:   var(--transition);
}
input:focus, textarea:focus, select:focus {
  border-color: var(--accent);
  box-shadow:   0 0 0 3px var(--accent-dim);
}
textarea { resize: vertical; min-height: 80px; }
select option { background: var(--bg-tertiary); }

/* ── Toast Notifications ───────────────────────────────────── */
#toast-container {
  position:  fixed;
  bottom:    24px;
  right:     24px;
  z-index:   9999;
  display:   flex;
  flex-direction: column;
  gap:       10px;
}
.toast {
  padding:       12px 18px;
  border-radius: var(--radius);
  font-size:     .875rem;
  box-shadow:    var(--shadow);
  animation:     slideIn .25s ease;
  max-width:     360px;
  border-left:   3px solid;
}
.toast-success { background: #122116; border-color: var(--success); color: var(--success); }
.toast-error   { background: #1a0e0e; border-color: var(--danger);  color: var(--danger); }
.toast-info    { background: #0d1a2e; border-color: var(--accent);  color: var(--accent); }
@keyframes slideIn {
  from { transform: translateX(120%); opacity: 0; }
  to   { transform: translateX(0);    opacity: 1; }
}

/* ── Login Page ────────────────────────────────────────────── */
#login-page {
  min-height: 100vh;
  display:    flex;
  align-items: center;
  justify-content: center;
  padding:    24px;
  background: radial-gradient(ellipse at 60% 40%, rgba(88,166,255,.07) 0%, transparent 60%),
              var(--bg-primary);
}
.login-card {
  width:         100%;
  max-width:     400px;
  background:    var(--bg-secondary);
  border:        1px solid var(--border);
  border-radius: 12px;
  padding:       40px 36px;
  box-shadow:    var(--shadow);
}
.login-logo {
  text-align: center;
  margin-bottom: 32px;
}
.login-logo .logo-icon {
  font-size: 2.5rem;
  display:   block;
  margin-bottom: 8px;
}
.login-logo h1 {
  font-size:   1.5rem;
  color:       var(--text-primary);
  letter-spacing: -.02em;
}
.login-logo p {
  font-size:  .8125rem;
  color:      var(--text-muted);
  margin-top: 4px;
}
.login-form { display: flex; flex-direction: column; gap: 18px; }
.login-form .btn-primary { width: 100%; justify-content: center; padding: 11px; }
.login-footer {
  margin-top:  20px;
  text-align:  center;
  font-size:   .8125rem;
  color:       var(--text-muted);
}
.login-footer a { font-weight: 500; }

/* ── Register Modal ────────────────────────────────────────── */
.modal-overlay {
  position:   fixed;
  inset:      0;
  background: rgba(0,0,0,.7);
  display:    flex;
  align-items: center;
  justify-content: center;
  z-index:    1000;
  padding:    24px;
  backdrop-filter: blur(4px);
}
.modal {
  background:    var(--bg-secondary);
  border:        1px solid var(--border);
  border-radius: 12px;
  padding:       32px;
  width:         100%;
  max-width:     480px;
  box-shadow:    var(--shadow);
}
.modal h2 { margin-bottom: 24px; font-size: 1.125rem; }
.modal-actions {
  display:   flex;
  gap:       10px;
  margin-top: 24px;
  justify-content: flex-end;
}

/* ── App Layout ────────────────────────────────────────────── */
#app {
  display:        flex;
  flex-direction: column;
  min-height:     100vh;
}

/* ── Header ────────────────────────────────────────────────── */
.app-header {
  position:   sticky;
  top:        0;
  z-index:    100;
  background: var(--bg-secondary);
  border-bottom: 1px solid var(--border);
  padding:    0 24px;
  height:     56px;
  display:    flex;
  align-items: center;
  gap:        16px;
}
.header-brand {
  font-weight:   700;
  font-size:     1.0625rem;
  color:         var(--text-primary);
  display:       flex;
  align-items:   center;
  gap:           8px;
  letter-spacing: -.01em;
  white-space:   nowrap;
}
.header-spacer { flex: 1; }
.header-user {
  display:    flex;
  align-items: center;
  gap:        12px;
  font-size:  .875rem;
  color:      var(--text-secondary);
}
.user-badge {
  background:    var(--accent-dim);
  color:         var(--accent);
  padding:       3px 8px;
  border-radius: 20px;
  font-size:     .75rem;
  font-weight:   600;
  text-transform: uppercase;
  letter-spacing: .05em;
}
.user-badge.supervisor { background: rgba(63,185,80,.12); color: var(--success); }

/* ── Tabs ──────────────────────────────────────────────────── */
.tab-bar {
  display:       flex;
  gap:           2px;
  border-bottom: 1px solid var(--border);
  background:    var(--bg-secondary);
  padding:       0 24px;
}
.tab-btn {
  padding:       12px 16px;
  font-size:     .875rem;
  font-weight:   500;
  color:         var(--text-muted);
  cursor:        pointer;
  border:        none;
  background:    transparent;
  border-bottom: 2px solid transparent;
  margin-bottom: -1px;
  transition:    var(--transition);
  display:       flex;
  align-items:   center;
  gap:           6px;
}
.tab-btn:hover  { color: var(--text-primary); }
.tab-btn.active { color: var(--accent); border-bottom-color: var(--accent); }
.tab-badge {
  background:    var(--danger);
  color:         #fff;
  font-size:     .6875rem;
  font-weight:   700;
  padding:       1px 6px;
  border-radius: 10px;
  min-width:     18px;
  text-align:    center;
}

/* ── Main Content ──────────────────────────────────────────── */
.app-main {
  flex:       1;
  padding:    24px;
  max-width:  900px;
  width:      100%;
  margin:     0 auto;
}
.tab-panel { display: none; animation: fadeIn .2s ease; }
.tab-panel.active { display: block; }
@keyframes fadeIn { from { opacity:0; transform:translateY(4px); } to { opacity:1; transform:none; } }

/* ── Notes Panel ───────────────────────────────────────────── */
.topic-selector {
  background:    var(--bg-secondary);
  border:        1px solid var(--border);
  border-radius: var(--radius);
  padding:       20px;
  margin-bottom: 20px;
  display:       flex;
  gap:           12px;
  flex-wrap:     wrap;
  align-items:   flex-end;
}
.topic-selector .form-group { flex: 1; min-width: 180px; }
.topic-selector label { font-size: .8125rem; }

.new-entry-box {
  background:    var(--bg-secondary);
  border:        1px solid var(--border);
  border-radius: var(--radius);
  padding:       20px;
  margin-bottom: 24px;
}
.new-entry-box h3 { font-size: .9375rem; margin-bottom: 14px; color: var(--text-secondary); }
.entry-form { display: flex; flex-direction: column; gap: 12px; }
.entry-form-actions { display: flex; gap: 10px; align-items: center; }

/* Entries list */
.entries-header {
  display:       flex;
  align-items:   center;
  gap:           12px;
  margin-bottom: 16px;
}
.entries-header h3 { font-size: .9375rem; color: var(--text-secondary); flex: 1; }

.entry-card {
  background:    var(--bg-secondary);
  border:        1px solid var(--border);
  border-radius: var(--radius);
  padding:       16px 20px;
  margin-bottom: 10px;
  transition:    var(--transition);
  animation:     slideDown .2s ease;
}
@keyframes slideDown {
  from { opacity:0; transform: translateY(-6px); }
  to   { opacity:1; transform: none; }
}
.entry-card:hover { border-color: var(--border-hover); }
.entry-card.deleted { opacity: .55; border-style: dashed; }
.entry-card.deleted .entry-text { text-decoration: line-through; color: var(--text-muted); }

.entry-meta {
  display:       flex;
  align-items:   center;
  gap:           10px;
  margin-bottom: 10px;
  font-size:     .8125rem;
}
.entry-time {
  font-family: var(--font-mono);
  color:       var(--text-muted);
  font-size:   .75rem;
}
.entry-author {
  font-weight: 600;
  color:       var(--accent);
}
.entry-deleted-badge {
  background:    var(--danger-dim);
  color:         var(--danger);
  padding:       2px 8px;
  border-radius: 4px;
  font-size:     .7rem;
  font-weight:   600;
  text-transform: uppercase;
}
.entry-spacer { flex: 1; }
.entry-text {
  color:       var(--text-primary);
  font-size:   .9375rem;
  line-height: 1.65;
  white-space: pre-wrap;
  word-break:  break-word;
}

/* ── Cards (admin) ─────────────────────────────────────────── */
.card {
  background:    var(--bg-secondary);
  border:        1px solid var(--border);
  border-radius: var(--radius);
  overflow:      hidden;
  margin-bottom: 20px;
}
.card-header {
  padding:       16px 20px;
  border-bottom: 1px solid var(--border);
  display:       flex;
  align-items:   center;
  gap:           12px;
}
.card-header h3 { font-size: .9375rem; flex: 1; }
.card-body { padding: 0; }

/* ── Table ─────────────────────────────────────────────────── */
.data-table {
  width:          100%;
  border-collapse: collapse;
  font-size:      .875rem;
}
.data-table th {
  padding:        10px 16px;
  text-align:     left;
  font-weight:    600;
  font-size:      .75rem;
  color:          var(--text-muted);
  text-transform: uppercase;
  letter-spacing: .05em;
  border-bottom:  1px solid var(--border);
  background:     var(--bg-tertiary);
}
.data-table td {
  padding:     12px 16px;
  border-bottom: 1px solid var(--border);
  color:       var(--text-primary);
  vertical-align: middle;
}
.data-table tr:last-child td { border-bottom: none; }
.data-table tr:hover td { background: var(--bg-tertiary); }
.data-table .actions { display: flex; gap: 6px; flex-wrap: wrap; }

/* Status badges */
.badge {
  display:       inline-flex;
  padding:       3px 8px;
  border-radius: 4px;
  font-size:     .7rem;
  font-weight:   700;
  text-transform: uppercase;
  letter-spacing: .05em;
}
.badge-active   { background: rgba(63,185,80,.12);  color: var(--success); }
.badge-inactive { background: rgba(248,81,73,.12);  color: var(--danger); }
.badge-pending  { background: rgba(210,153,34,.12); color: var(--warning); }

/* Empty state */
.empty-state {
  text-align: center;
  padding:    48px 24px;
  color:      var(--text-muted);
  font-size:  .9375rem;
}
.empty-state .empty-icon { font-size: 2.5rem; display: block; margin-bottom: 12px; }

/* Loading spinner */
.spinner {
  display:       inline-block;
  width:         20px;
  height:        20px;
  border:        2px solid var(--border);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation:     spin .6s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }

/* ── Responsive ────────────────────────────────────────────── */
@media (max-width: 640px) {
  .app-header   { padding: 0 16px; }
  .tab-bar      { padding: 0 16px; overflow-x: auto; }
  .app-main     { padding: 16px; }
  .topic-selector { flex-direction: column; }
  .login-card   { padding: 28px 20px; }
  .data-table th, .data-table td { padding: 10px 12px; }
  .data-table .actions { flex-direction: column; }
  .header-user .username { display: none; }
}

/* ── Password strength indicator ───────────────────────────── */
.pw-strength { display: flex; gap: 4px; margin-top: 6px; }
.pw-bar {
  flex: 1; height: 3px; border-radius: 2px;
  background: var(--border);
  transition: background .3s;
}
.pw-bar.weak   { background: var(--danger); }
.pw-bar.medium { background: var(--warning); }
.pw-bar.strong { background: var(--success); }
.pw-label { font-size: .75rem; margin-top: 4px; color: var(--text-muted); }