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

:root {
  --header-bg:   #0f172a;
  --header-h:    56px;
  --bg:          #ffffff;
  --bg-subtle:   #f8fafc;
  --accent:      #0d9488;
  --accent-light:#ccfbf1;
  --primary:     #1e293b;
  --border:      #e2e8f0;
  --border-hover:#94a3b8;
  --text:        #0f172a;
  --text-muted:  #64748b;
  --text-light:  #94a3b8;
  --danger:      #ef4444;
  --success:     #10b981;
  --radius:      12px;
  --form-w:      380px;
  --transition:  .17s ease;
}

html, body {
  height: 100%;
  font-family: 'Inter', system-ui, -apple-system, sans-serif;
  font-size: 14px;
  color: var(--text);
  background: var(--bg);
  line-height: 1.6;
}

::-webkit-scrollbar { width: 5px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 99px; }

/* ── Header ─────────────────────────────────────────────────── */
.header {
  position: fixed;
  top: 0; left: 0; right: 0;
  height: var(--header-h);
  background: var(--header-bg);
  z-index: 100;
  display: flex;
  align-items: center;
}

.header-inner {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 28px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.header-logo {
  display: flex;
  align-items: center;
  gap: 9px;
  color: #fff;
  font-size: 15px;
  font-weight: 600;
  letter-spacing: -.2px;
}

.header-logo svg { opacity: .85; }

/* ── Status badge ───────────────────────────────────────────── */
.status-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 10px;
  border-radius: 99px;
  font-size: 12px;
  font-weight: 500;
  border: 1px solid transparent;
}

.status-dot {
  width: 7px; height: 7px;
  border-radius: 50%; flex-shrink: 0;
}

.status-badge.checking { background:rgba(148,163,184,.15); border-color:rgba(148,163,184,.25); }
.status-badge.checking .status-dot { background:#94a3b8; animation: pulse 1.2s infinite; }
.status-badge.checking .status-text { color:#94a3b8; }
.status-badge.online  { background:rgba(16,185,129,.12); border-color:rgba(16,185,129,.25); }
.status-badge.online  .status-dot { background:var(--success); }
.status-badge.online  .status-text { color:#6ee7b7; }
.status-badge.offline { background:rgba(239,68,68,.12); border-color:rgba(239,68,68,.25); }
.status-badge.offline .status-dot { background:var(--danger); }
.status-badge.offline .status-text { color:#fca5a5; }

@keyframes pulse { 0%,100%{opacity:1} 50%{opacity:.25} }

/* ── Page offset for fixed header ───────────────────────────── */
#page-home, #page-workspace { padding-top: var(--header-h); }

/* ═══════════════════════════════════════════════════════════════
   HOME PAGE
   ════════════════════════════════════════════════════════════ */

/* Hero */
.hero {
  text-align: center;
  padding: 64px 24px 48px;
  max-width: 680px;
  margin: 0 auto;
}

.hero h1 {
  font-size: clamp(1.75rem, 4vw, 2.5rem);
  font-weight: 700;
  letter-spacing: -.5px;
  color: var(--text);
  margin-bottom: 14px;
  line-height: 1.2;
}

.hero p {
  font-size: 1rem;
  color: var(--text-muted);
  line-height: 1.7;
}

.hero-cta {
  color: var(--accent);
  font-weight: 500;
}

/* Cards */
.cards-section {
  padding: 0 24px 56px;
}

.cards-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 20px;
  max-width: 1000px;
  margin: 0 auto;
}

.card {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px;
  cursor: pointer;
  display: flex;
  flex-direction: column;
  gap: 12px;
  transition: border-color var(--transition), box-shadow var(--transition), transform var(--transition);
  box-shadow: 0 1px 3px rgba(0,0,0,.04);
}

.card:hover {
  border-color: var(--border-hover);
  box-shadow: 0 4px 20px rgba(0,0,0,.08);
  transform: translateY(-2px);
}

.card-icon {
  display: flex;
  align-items: center;
  justify-content: flex-start;
}

.card h2 {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--text);
  margin: 0;
}

.card-desc {
  font-size: .875rem;
  color: var(--accent);
  font-weight: 500;
  line-height: 1.5;
}

.card-features {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 6px;
  flex: 1;
}

.card-features li {
  font-size: .8rem;
  color: var(--text-muted);
  padding-left: 14px;
  position: relative;
}

.card-features li::before {
  content: '•';
  position: absolute;
  left: 0;
  color: var(--text-light);
}

.btn-card {
  margin-top: 6px;
  width: 100%;
  padding: 10px 16px;
  background: var(--primary);
  color: #fff;
  border: none;
  border-radius: 8px;
  font-family: inherit;
  font-size: .875rem;
  font-weight: 600;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: space-between;
  transition: background var(--transition), transform var(--transition);
}

.btn-card:hover { background: #0f172a; transform: none; }
.btn-card span { font-size: 1rem; }

/* Levels */
.levels-section {
  text-align: center;
  padding: 0 24px 64px;
  border-top: 1px solid var(--border);
  padding-top: 40px;
  margin-top: 0;
}

.levels-section h3 {
  font-size: .75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: var(--text-light);
  margin-bottom: 16px;
}

.levels-list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  justify-content: center;
}

.level-badge {
  padding: 5px 14px;
  border: 1px solid var(--border);
  border-radius: 99px;
  font-size: .8rem;
  color: var(--text-muted);
  background: var(--bg-subtle);
}

/* ═══════════════════════════════════════════════════════════════
   WORKSPACE
   ════════════════════════════════════════════════════════════ */

.workspace {
  display: flex;
  height: calc(100vh - var(--header-h));
  overflow: hidden;
}

/* Form panel */
.form-panel {
  width: var(--form-w);
  min-width: var(--form-w);
  background: var(--bg-subtle);
  border-right: 1px solid var(--border);
  overflow-y: auto;
  padding: 24px 24px 40px;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.back-btn {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  background: none;
  border: 1px solid var(--border);
  border-radius: 7px;
  padding: 6px 12px;
  font-family: inherit;
  font-size: .8rem;
  font-weight: 500;
  color: var(--text-muted);
  cursor: pointer;
  transition: background var(--transition), border-color var(--transition);
  width: fit-content;
}

.back-btn:hover { background: var(--bg); border-color: var(--border-hover); color: var(--text); }

.plan-header { display: flex; flex-direction: column; gap: 4px; }

.plan-badge {
  font-size: .7rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: .8px;
  color: var(--accent);
  background: var(--accent-light);
  padding: 2px 8px;
  border-radius: 4px;
  width: fit-content;
}

.plan-title {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--text);
}

.plan-subtitle {
  font-size: .8rem;
  color: var(--text-muted);
  line-height: 1.5;
}

/* Form fields */
#lesson-form {
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.field-row {
  display: flex;
  gap: 10px;
}

.field-row .field { flex: 1; min-width: 0; }

.field {
  display: flex;
  flex-direction: column;
  gap: 5px;
}

label {
  font-size: .75rem;
  font-weight: 600;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: .4px;
}

.req { color: var(--danger); }

input, select, textarea {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 7px;
  color: var(--text);
  font-family: inherit;
  font-size: .875rem;
  padding: 8px 10px;
  transition: border-color var(--transition), box-shadow var(--transition);
  width: 100%;
  outline: none;
}

input:focus, select:focus, textarea:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(13,148,136,.1);
}

input::placeholder, textarea::placeholder { color: var(--text-light); }

textarea { resize: vertical; min-height: 64px; }

.btn-generate {
  padding: 11px 16px;
  background: var(--primary);
  border: none;
  border-radius: 8px;
  color: #fff;
  font-family: inherit;
  font-size: .875rem;
  font-weight: 600;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 7px;
  transition: background var(--transition), opacity var(--transition);
  margin-top: 4px;
}

.btn-generate:hover:not(:disabled) { background: #0f172a; }
.btn-generate:disabled { opacity: .55; cursor: not-allowed; }
.btn-generate.loading .btn-icon { animation: spin 1s linear infinite; display: inline-block; }
@keyframes spin { to { transform: rotate(360deg); } }

/* Output panel */
.output-panel {
  flex: 1;
  min-width: 0;
  overflow-y: auto;
  background: var(--bg);
  display: flex;
  flex-direction: column;
}

/* Empty state */
.out-empty {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 48px 40px;
  gap: 12px;
  color: var(--text-muted);
}

.out-empty-icon { opacity: .5; margin-bottom: 8px; }

.out-empty h3 {
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--text);
}

.out-empty p {
  max-width: 360px;
  font-size: .875rem;
  color: var(--text-muted);
  line-height: 1.7;
}

/* Result */
.out-result {
  flex: 1;
  display: flex;
  flex-direction: column;
}

.out-toolbar {
  position: sticky;
  top: 0;
  z-index: 5;
  background: var(--bg);
  border-bottom: 1px solid var(--border);
  padding: 10px 32px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

.out-title {
  font-size: .875rem;
  font-weight: 600;
  color: var(--text-muted);
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.out-actions { display: flex; gap: 8px; flex-shrink: 0; }

.btn-tool {
  padding: 5px 12px;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: var(--bg);
  color: var(--text-muted);
  font-family: inherit;
  font-size: .78rem;
  font-weight: 500;
  cursor: pointer;
  transition: background var(--transition), border-color var(--transition);
}

.btn-tool:hover { background: var(--bg-subtle); border-color: var(--border-hover); color: var(--text); }

/* ── Markdown output ─────────────────────────────────────────── */
.lesson-output {
  padding: 32px 40px 60px;
  max-width: 780px;
  width: 100%;
}

.lesson-output h1 { font-size: 1.6rem; font-weight: 800; margin-bottom: 20px; color: var(--text); }
.lesson-output h2 { font-size: 1.1rem; font-weight: 700; margin: 28px 0 10px; color: var(--text); border-bottom: 2px solid var(--accent-light); padding-bottom: 5px; }
.lesson-output h3 { font-size: .95rem; font-weight: 700; margin: 18px 0 7px; color: var(--accent); }
.lesson-output h4 { font-size: .8rem; font-weight: 700; margin: 14px 0 5px; text-transform: uppercase; letter-spacing: .5px; color: var(--text-muted); }
.lesson-output p { margin-bottom: 9px; font-size: .9rem; }
.lesson-output ul, .lesson-output ol { margin: 6px 0 10px 20px; }
.lesson-output li { margin-bottom: 4px; font-size: .875rem; }
.lesson-output li::marker { color: var(--accent); }
.lesson-output strong { font-weight: 600; }
.lesson-output hr { border: none; border-top: 1px solid var(--border); margin: 24px 0; }
.lesson-output code { background: var(--bg-subtle); border: 1px solid var(--border); border-radius: 4px; font-size: .8rem; padding: 1px 5px; color: var(--accent); font-family: monospace; }
.lesson-output blockquote { border-left: 3px solid var(--accent); padding: 8px 14px; margin: 10px 0; background: var(--accent-light); border-radius: 0 6px 6px 0; color: #0f766e; font-size: .875rem; }

.lesson-output .cursor {
  display: inline-block; width: 2px; height: 1em;
  background: var(--accent); animation: blink .8s step-end infinite;
  vertical-align: text-bottom; margin-left: 2px; border-radius: 1px;
}
@keyframes blink { 0%,100%{opacity:1} 50%{opacity:0} }

/* Error */
.out-error {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 48px 40px;
  gap: 12px;
}

.out-error-icon { font-size: 44px; }
.out-error h3 { font-size: 1.1rem; font-weight: 700; color: var(--danger); }
.out-error p { color: var(--text-muted); font-size: .875rem; max-width: 400px; }

.error-steps {
  background: var(--bg-subtle);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 18px 24px;
  text-align: left;
  max-width: 400px;
  width: 100%;
  font-size: .875rem;
}

.error-steps ol { margin: 8px 0 0 18px; display: flex; flex-direction: column; gap: 6px; }
.error-steps li { color: var(--text-muted); }
.error-steps code { background: #f1f5f9; border: 1px solid var(--border); border-radius: 3px; padding: 1px 5px; font-family: monospace; font-size: .78rem; color: var(--accent); }

.btn-retry {
  padding: 9px 22px;
  background: var(--danger);
  border: none; border-radius: 7px;
  color: #fff; font-family: inherit;
  font-size: .875rem; font-weight: 600;
  cursor: pointer;
}

.btn-retry:hover { background: #dc2626; }

/* ── Multi-select component ─────────────────────────────────── */
.ms-wrapper {
  position: relative;
}

.ms-control {
  display: flex;
  align-items: flex-start;
  gap: 6px;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 7px;
  padding: 7px 10px;
  cursor: pointer;
  min-height: 36px;
  transition: border-color var(--transition), box-shadow var(--transition);
  user-select: none;
}

.ms-control:focus,
.ms-control.open {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(13,148,136,.1);
  outline: none;
}

.ms-control.invalid {
  border-color: var(--danger);
  box-shadow: 0 0 0 3px rgba(239,68,68,.1);
}

.ms-tags {
  flex: 1;
  display: flex;
  flex-wrap: wrap;
  gap: 4px;
  min-width: 0;
}

.ms-placeholder {
  color: var(--text-light);
  font-size: .875rem;
  line-height: 1.5;
}

.ms-tag {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  background: var(--accent-light);
  color: #0f766e;
  border-radius: 4px;
  font-size: .72rem;
  font-weight: 500;
  padding: 2px 6px;
  max-width: 100%;
}

.ms-tag span {
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  max-width: 180px;
}

.ms-tag-remove {
  cursor: pointer;
  opacity: .6;
  flex-shrink: 0;
  font-size: .8rem;
  line-height: 1;
  transition: opacity .1s;
}

.ms-tag-remove:hover { opacity: 1; }

.ms-chevron {
  flex-shrink: 0;
  color: var(--text-light);
  margin-top: 2px;
  transition: transform var(--transition);
}

.ms-control.open .ms-chevron { transform: rotate(180deg); }

/* Dropdown panel */
.ms-panel {
  position: absolute;
  top: calc(100% + 4px);
  left: 0; right: 0;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 9px;
  box-shadow: 0 8px 32px rgba(0,0,0,.12);
  z-index: 200;
  overflow: hidden;
  display: flex;
  flex-direction: column;
  max-height: 320px;
}

.ms-search-wrap {
  display: flex;
  align-items: center;
  gap: 7px;
  padding: 9px 12px;
  border-bottom: 1px solid var(--border);
  flex-shrink: 0;
}

.ms-search {
  flex: 1;
  border: none;
  outline: none;
  font-family: inherit;
  font-size: .8rem;
  color: var(--text);
  background: transparent;
  padding: 0;
}

.ms-search::placeholder { color: var(--text-light); }

.ms-list {
  overflow-y: auto;
  flex: 1;
}

.ms-group-head {
  padding: 7px 12px 4px;
  font-size: .68rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: .6px;
  color: var(--text-light);
  background: var(--bg-subtle);
  border-top: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 1;
}

.ms-group-head:first-child { border-top: none; }

.ms-item {
  display: flex;
  align-items: center;
  gap: 9px;
  padding: 7px 12px;
  cursor: pointer;
  transition: background var(--transition);
}

.ms-item:hover { background: var(--bg-subtle); }

.ms-item.checked { background: var(--accent-light); }

.ms-item input[type="checkbox"] {
  width: 14px;
  height: 14px;
  accent-color: var(--accent);
  border-radius: 3px;
  flex-shrink: 0;
  cursor: pointer;
  margin: 0;
  padding: 0;
}

.ms-item span {
  font-size: .8rem;
  color: var(--text);
  line-height: 1.4;
}

.ms-item.hidden-item { display: none; }

.ms-no-results {
  padding: 16px 12px;
  text-align: center;
  font-size: .8rem;
  color: var(--text-light);
}

/* ── Utilities ───────────────────────────────────────────────── */
.hidden { display: none !important; }

/* ── Print ───────────────────────────────────────────────────── */
@media print {
  .header, .form-panel, .out-toolbar { display: none !important; }
  .workspace, #page-workspace { display: block; height: auto; overflow: visible; }
  .output-panel { overflow: visible; }
  .lesson-output { padding: 16px; max-width: 100%; }
}

/* ── Responsive ──────────────────────────────────────────────── */
@media (max-width: 700px) {
  .workspace { flex-direction: column; height: auto; overflow: visible; }
  .form-panel { width: 100%; min-width: 100%; }
  .output-panel { min-height: 50vh; }
  #page-workspace { height: auto; overflow: visible; }
  .lesson-output { padding: 20px; }
  .cards-grid { grid-template-columns: 1fr; }
}