:root {
  --bg: #0d1117;
  --bg-card: #161b22;
  --bg-input: #0d1117;
  --sidebar-bg: #161b22;
  --sidebar-w: 220px;
  --border: #21262d;
  --text: #c9d1d9;
  --text-dim: #8b949e;
  --text-bright: #f0f6fc;
  --accent: #58a6ff;
  --accent-hover: #79c0ff;
  --green: #238636;
  --green-bright: #3fb950;
  --red: #da3633;
  --red-bright: #f85149;
  --yellow: #d29922;
  --gold: #ffd700;
  --purple: #a371f7;
  --radius: 8px;
  --radius-sm: 6px;
}

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

html { font-size: 14px; scroll-behavior: smooth; }
body {
  font-family: 'Pretendard Variable', Pretendard, -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  min-height: 100vh;
}

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

.app {
  display: flex;
  min-height: 100vh;
}

/* ─── Sidebar ─── */
.sidebar {
  width: var(--sidebar-w);
  min-width: var(--sidebar-w);
  background: var(--sidebar-bg);
  border-right: 1px solid var(--border);
  position: fixed;
  top: 0;
  left: 0;
  bottom: 0;
  padding: 0;
  overflow-y: auto;
  box-sizing: border-box;
  z-index: 100;
  display: flex;
  flex-direction: column;
  scrollbar-width: thin;
  scrollbar-color: #30363d transparent;
}
.sidebar::-webkit-scrollbar { width: 6px; }
.sidebar::-webkit-scrollbar-thumb { background: #30363d; border-radius: 3px; }

.sidebar-logo {
  padding: 16px 12px 10px;
  border-bottom: 1px solid var(--border);
}
.sidebar-logo h1 {
  font-size: 18px;
  font-weight: 800;
  color: var(--text-bright);
  letter-spacing: -0.5px;
}
.sidebar-logo span {
  font-size: 11px;
  color: var(--text-dim);
  letter-spacing: 0.5px;
}

.sidebar-auth {
  margin: 8px 16px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--border);
}
.sidebar-auth-btn {
  display: flex;
  align-items: center;
  gap: 8px;
  width: 100%;
  padding: 8px 12px;
  background: transparent;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  color: var(--text);
  font-size: 13px;
  cursor: pointer;
  transition: background .15s;
}
.sidebar-auth-btn:hover { background: #1c2128; }
.sidebar-auth-btn.authenticated {
  border-color: var(--green);
  color: var(--green-bright);
}

.sidebar-pw-area {
  margin: 4px 12px 8px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--border);
}
.sidebar-pw-area label {
  display: block;
  font-size: 11px;
  color: var(--text-dim);
  margin-bottom: 4px;
  font-weight: 600;
  letter-spacing: 0.5px;
}
.sidebar-pw-wrap {
  display: flex;
  gap: 4px;
  width: 100%;
}
.sidebar-pw-wrap input {
  flex: 1;
  min-width: 0;
  padding: 6px 8px;
  background: var(--bg-input);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  color: var(--text);
  font-size: 12px;
  outline: none;
}
.sidebar-pw-wrap input:focus { border-color: var(--accent); }
.sidebar-pw-wrap button {
  flex-shrink: 0;
  padding: 6px 10px;
  background: var(--green);
  border: none;
  border-radius: var(--radius-sm);
  color: #fff;
  font-size: 11px;
  font-weight: 700;
  cursor: pointer;
  white-space: nowrap;
}
.sidebar-pw-status {
  font-size: 11px;
  margin-top: 4px;
  padding: 4px 8px;
  border-radius: 4px;
}
.sidebar-pw-status.ok { background: #23863622; color: var(--green-bright); }
.sidebar-pw-status.fail { background: #da363322; color: var(--red-bright); }
.sidebar-auth-status {
  display: flex; align-items: center; gap: 8px; justify-content: space-between;
}
.sidebar-auth-badge {
  font-size: 12px; font-weight: 600; color: var(--green-bright);
  background: #23863622; padding: 5px 10px; border-radius: 6px;
}
.sidebar-logout-btn {
  font-size: 11px; padding: 4px 10px; border-radius: 6px;
  border: 1px solid #da363666; background: #da363622; color: #f85149;
  cursor: pointer; transition: background 0.2s;
}
.sidebar-logout-btn:hover { background: #da363644; }

.sidebar-section-title {
  padding: 12px 12px 4px;
  font-size: 11px;
  color: var(--text-dim);
  font-weight: 600;
  letter-spacing: 1px;
  text-transform: uppercase;
}

.sidebar-links {
  padding: 4px 8px;
  display: flex;
  flex-direction: column;
  gap: 1px;
}
.sidebar-links a, .sidebar-links button.nav-link {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 8px 12px;
  border-radius: var(--radius-sm);
  color: var(--text);
  font-size: 13px;
  transition: background .15s, color .15s;
  border: none;
  background: none;
  cursor: pointer;
  width: 100%;
  text-align: left;
  font-family: inherit;
}
.sidebar-links a:hover, .sidebar-links button.nav-link:hover {
  background: #1c2128;
  color: var(--text-bright);
}
.sidebar-links a.active {
  background: #1f6feb22;
  color: var(--accent);
  font-weight: 600;
}
.sidebar-links a svg, .sidebar-links button.nav-link svg {
  flex-shrink: 0;
  opacity: .7;
}
.sidebar-links a.active svg { opacity: 1; }

.sidebar-tree-toggle {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 8px 12px;
  color: var(--text-dim);
  font-size: 12px;
  font-weight: 600;
  cursor: pointer;
  border: none;
  background: none;
  width: 100%;
  text-align: left;
  font-family: inherit;
}
.sidebar-tree-toggle:hover { color: var(--text); }
.sidebar-tree-toggle .arrow {
  transition: transform .2s;
  font-size: 10px;
}
.sidebar-tree-toggle.open .arrow { transform: rotate(90deg); }
.sidebar-tree-children {
  display: none;
  padding-left: 12px;
}
.sidebar-tree-children.open { display: block; }

.sidebar-quick-links {
  padding: 8px 12px;
  display: flex;
  flex-direction: column;
  gap: 6px;
  border-bottom: 1px solid var(--border);
}
.sidebar-quick-links a {
  display: block;
  font-size: 12px;
  padding: 6px 10px;
  border: 1px solid;
  border-radius: var(--radius-sm);
  text-align: center;
  font-weight: 600;
  transition: opacity .15s;
}
.sidebar-quick-links a:hover { opacity: .85; }
.sidebar-ql-group {
  border: 1px solid;
  border-radius: var(--radius-sm);
  overflow: hidden;
}
.sidebar-ql-group-label {
  display: block;
  font-size: 12px;
  font-weight: 600;
  padding: 6px 10px 4px;
  text-align: center;
}
.sidebar-ql-group-items {
  display: flex;
  gap: 4px;
  padding: 0 6px 6px;
}
.sidebar-ql-group-items a {
  flex: 1;
  font-size: 11px;
  padding: 5px 6px;
}

.sidebar-bottom {
  margin-top: auto;
  padding: 12px 12px;
  border-top: 1px solid var(--border);
}
.sidebar-bottom p {
  font-size: 11px;
  color: var(--text-dim);
  line-height: 1.5;
}

.sidebar-hamburger {
  display: none;
  position: fixed;
  top: 12px;
  left: 12px;
  z-index: 200;
  width: 40px;
  height: 40px;
  background: var(--sidebar-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  color: var(--text);
  cursor: pointer;
  align-items: center;
  justify-content: center;
}
.sidebar-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,.6);
  z-index: 90;
}

/* ─── Main Content ─── */
.main {
  flex: 1;
  margin-left: var(--sidebar-w);
  min-height: 100vh;
  min-width: 0;
  overflow-x: hidden;
}

/* ─── Landing Page ─── */
.hero {
  padding: 60px 40px;
  text-align: center;
  background: linear-gradient(135deg, #0d1117 0%, #161b22 50%, #1c2128 100%);
  border-bottom: 1px solid var(--border);
}
.hero h2 {
  font-size: 32px;
  font-weight: 800;
  color: var(--text-bright);
  margin-bottom: 12px;
  line-height: 1.3;
}
.hero .sub {
  font-size: 16px;
  color: var(--accent);
  font-weight: 600;
}
.hero .tagline {
  font-size: 14px;
  color: var(--text-dim);
  margin-top: 8px;
}
.hero .badge {
  display: inline-block;
  margin-top: 16px;
  padding: 6px 16px;
  background: var(--green);
  color: #fff;
  border-radius: 20px;
  font-size: 13px;
  font-weight: 700;
}

.section {
  padding: 48px 40px;
  border-bottom: 1px solid var(--border);
}
.section:last-child { border-bottom: none; }
.section-title {
  font-size: 22px;
  font-weight: 800;
  color: var(--text-bright);
  margin-bottom: 24px;
  text-align: center;
}
.section-subtitle {
  font-size: 14px;
  color: var(--text-dim);
  text-align: center;
  margin-top: -16px;
  margin-bottom: 24px;
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
  max-width: 900px;
  margin: 0 auto;
}
.feature-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  text-align: center;
}
.feature-card img {
  width: 64px;
  height: 64px;
  margin-bottom: 16px;
}
.feature-card h3 {
  font-size: 16px;
  font-weight: 700;
  color: var(--text-bright);
  margin-bottom: 8px;
}
.feature-card p {
  font-size: 13px;
  color: var(--text-dim);
  line-height: 1.5;
}

.steps-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
  max-width: 900px;
  margin: 0 auto;
}
.step-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  position: relative;
}
.step-num {
  position: absolute;
  top: -12px;
  left: 20px;
  background: var(--accent);
  color: #fff;
  width: 28px;
  height: 28px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 14px;
  font-weight: 800;
}
.step-card h3 {
  font-size: 15px;
  font-weight: 700;
  color: var(--text-bright);
  margin-bottom: 8px;
  margin-top: 4px;
}
.step-card .teacher {
  font-size: 12px;
  color: var(--accent);
  font-weight: 600;
  margin-bottom: 6px;
}
.step-card p {
  font-size: 13px;
  color: var(--text-dim);
  line-height: 1.5;
}

.pricing-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
  max-width: 700px;
  margin: 0 auto;
}
.price-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px;
  text-align: center;
}
.price-card.featured {
  border-color: var(--gold);
  box-shadow: 0 0 20px rgba(255,215,0,.1);
}
.price-card h3 {
  font-size: 18px;
  font-weight: 700;
  color: var(--text-bright);
  margin-bottom: 12px;
}
.price-card .price {
  font-size: 28px;
  font-weight: 800;
  color: var(--gold);
  margin-bottom: 16px;
}
.price-card .price small {
  font-size: 14px;
  color: var(--text-dim);
  font-weight: 400;
}
.price-card ul {
  list-style: none;
  text-align: left;
  margin-bottom: 20px;
}
.price-card ul li {
  padding: 6px 0;
  font-size: 13px;
  color: var(--text);
  border-bottom: 1px solid var(--border);
}
.price-card ul li::before {
  content: '✓ ';
  color: var(--green-bright);
  font-weight: 700;
}

.stories-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
  max-width: 900px;
  margin: 0 auto;
}
.story-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
}
.story-card img {
  width: 100%;
  height: 180px;
  object-fit: cover;
}
.story-card .caption {
  padding: 12px 16px;
  font-size: 13px;
  color: var(--text);
  font-weight: 600;
}

.checklist-section {
  max-width: 700px;
  margin: 0 auto;
}
.checklist-header {
  text-align: center;
  margin-bottom: 24px;
}
.checklist-header .alert {
  display: inline-block;
  padding: 8px 20px;
  background: var(--red);
  color: #fff;
  border-radius: 20px;
  font-size: 13px;
  font-weight: 700;
  margin-bottom: 8px;
}
.checklist-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 8px;
}
.check-item {
  display: flex;
  align-items: flex-start;
  gap: 8px;
  padding: 8px 12px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  font-size: 13px;
  color: var(--text);
}
.check-item::before {
  content: '☑';
  color: var(--yellow);
  flex-shrink: 0;
}

.company-info {
  max-width: 700px;
  margin: 0 auto;
  text-align: center;
}
.company-info p {
  font-size: 12px;
  color: var(--text-dim);
  line-height: 1.8;
}
.company-info .cert {
  display: inline-block;
  margin-top: 12px;
  padding: 6px 16px;
  background: var(--green);
  color: #fff;
  border-radius: 4px;
  font-size: 12px;
  font-weight: 600;
}

/* ─── Buttons ─── */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  padding: 10px 20px;
  border: none;
  border-radius: var(--radius-sm);
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  transition: opacity .15s;
  font-family: inherit;
}
.btn:hover { opacity: .9; }
.btn-primary { background: var(--accent); color: #fff; }
.btn-green { background: var(--green); color: #fff; }
.btn-red { background: var(--red); color: #fff; }
.btn-outline {
  background: transparent;
  border: 1px solid var(--border);
  color: var(--text);
}
.btn-outline:hover { border-color: var(--accent); color: var(--accent); }
.btn-gold {
  background: linear-gradient(135deg, #ffd700, #f0c000);
  color: #000;
  font-weight: 800;
}
.btn-block { width: 100%; }
.btn-sm { padding: 6px 12px; font-size: 12px; }
.btn-lg { padding: 14px 28px; font-size: 16px; }

/* ─── Forms ─── */
.form-page {
  max-width: 480px;
  margin: 40px auto;
  padding: 0 20px;
}
.form-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 32px;
}
.form-card h2 {
  font-size: 20px;
  font-weight: 800;
  color: var(--text-bright);
  margin-bottom: 24px;
  text-align: center;
}
.form-group {
  margin-bottom: 16px;
}
.form-group label {
  display: block;
  font-size: 13px;
  font-weight: 600;
  color: var(--text);
  margin-bottom: 6px;
}
.form-group input, .form-group select, .form-group textarea {
  width: 100%;
  padding: 10px 12px;
  background: var(--bg-input);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  color: var(--text);
  font-size: 14px;
  font-family: inherit;
  outline: none;
}
.form-group input:focus, .form-group select:focus, .form-group textarea:focus {
  border-color: var(--accent);
}
.form-group textarea { resize: vertical; min-height: 80px; }
.form-msg {
  padding: 12px 16px;
  border-radius: var(--radius-sm);
  font-size: 13px;
  margin-top: 16px;
  line-height: 1.5;
}
.form-msg.success { background: #23863622; color: var(--green-bright); border: 1px solid #23863644; }
.form-msg.error { background: #da363322; color: var(--red-bright); border: 1px solid #da363344; }
.form-msg.info { background: #58a6ff22; color: var(--accent); border: 1px solid #58a6ff44; }

.form-tabs {
  display: flex;
  gap: 0;
  margin-bottom: 24px;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  overflow: hidden;
}
.form-tab {
  flex: 1;
  padding: 10px;
  text-align: center;
  font-size: 14px;
  font-weight: 600;
  background: transparent;
  border: none;
  color: var(--text-dim);
  cursor: pointer;
  font-family: inherit;
  transition: background .15s, color .15s;
}
.form-tab.active {
  background: var(--accent);
  color: #fff;
}
.form-tab:not(.active):hover { background: #1c2128; }

/* ─── Admin ─── */
.admin-page {
  padding: 24px 32px;
}
.admin-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 24px;
}
.admin-header h2 {
  font-size: 22px;
  font-weight: 800;
  color: var(--text-bright);
}

.admin-login {
  max-width: 360px;
  margin: 80px auto;
  padding: 0 20px;
}

.stats-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 8px;
  margin-bottom: 16px;
}
.stat-chip {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 10px 8px;
  text-align: center;
}
.stat-chip.spacer {
  background: none;
  border: none;
}
.stat-chip .num {
  font-size: 16px;
  font-weight: 800;
  color: var(--text-bright);
  display: block;
}
.stat-chip .label {
  font-size: 10px;
  color: var(--text-dim);
  display: block;
  margin-top: 2px;
}
.stat-chip.pending .num { color: var(--yellow); font-size: 20px; }
.stat-chip.warn .num { color: #da3633; font-size: 20px; }
.stat-chip.revenue .num { color: var(--gold); font-size: 20px; }

.admin-filters {
  display: flex;
  gap: 8px;
  margin-bottom: 16px;
  flex-wrap: wrap;
}
.admin-filters select {
  padding: 6px 12px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  color: var(--text);
  font-size: 13px;
  font-family: inherit;
}

.admin-table-wrap {
  overflow-x: auto;
  border: 1px solid var(--border);
  border-radius: var(--radius);
}
table.admin-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 13px;
}
table.admin-table th {
  background: var(--bg-card);
  color: var(--text-dim);
  font-weight: 600;
  text-align: left;
  padding: 10px 12px;
  border-bottom: 1px solid var(--border);
  white-space: nowrap;
}
table.admin-table td {
  padding: 10px 12px;
  border-bottom: 1px solid var(--border);
  white-space: nowrap;
}
table.admin-table tr:hover td { background: #1c2128; }

.badge-tier {
  display: inline-block;
  padding: 2px 8px;
  border-radius: 10px;
  font-size: 11px;
  font-weight: 700;
}
.badge-tier.free { background: #58a6ff33; color: var(--accent); }
.badge-tier.paid { background: #ffd70033; color: var(--gold); }
.badge-tier.semiauto { background: #a371f733; color: #d2a8ff; }
.badge-tier.pdf { background: #f0883e33; color: #ffa657; }
.badge-status {
  display: inline-block;
  padding: 2px 8px;
  border-radius: 10px;
  font-size: 11px;
  font-weight: 700;
}
.badge-status.active { background: #23863633; color: var(--green-bright); }
.badge-status.pending { background: #d2992233; color: var(--yellow); }
.badge-status.expired { background: #8b949e33; color: var(--text-dim); }
.badge-status.rejected { background: #da363333; color: var(--red-bright); }

.action-btns {
  display: flex;
  gap: 4px;
}
.action-btns button {
  padding: 4px 8px;
  font-size: 11px;
  border: none;
  border-radius: 4px;
  cursor: pointer;
  font-weight: 600;
  font-family: inherit;
}
.action-btns .approve { background: var(--green); color: #fff; }
.action-btns .reject { background: var(--red); color: #fff; }
.action-btns .detail { background: var(--border); color: var(--text); }

/* ─── Settings Panel ─── */
.settings-section {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  margin-bottom: 20px;
}
.settings-section h3 {
  font-size: 16px;
  font-weight: 700;
  color: var(--text-bright);
  margin-bottom: 16px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--border);
}

/* ─── Modal ─── */
.modal-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,.7);
  z-index: 500;
  align-items: center;
  justify-content: center;
}
.modal-overlay.open { display: flex; }
.modal-box {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px;
  max-width: 500px;
  width: 90%;
  max-height: 80vh;
  overflow-y: auto;
}
.modal-box h3 {
  font-size: 18px;
  font-weight: 700;
  color: var(--text-bright);
  margin-bottom: 16px;
}
.modal-close {
  float: right;
  background: none;
  border: none;
  color: var(--text-dim);
  font-size: 20px;
  cursor: pointer;
}

/* ─── Responsive ─── */
@media (max-width: 768px) {
  .sidebar {
    transform: translateX(-100%);
    transition: transform .3s;
  }
  .sidebar.open { transform: translateX(0); }
  .sidebar-hamburger { display: flex; }
  .sidebar-overlay.open { display: block; }
  .main { margin-left: 0; }

  .hero { padding: 40px 20px; }
  .hero h2 { font-size: 22px; }
  .section { padding: 32px 16px; }
  .features-grid, .steps-grid, .stories-grid { grid-template-columns: 1fr; }
  .pricing-grid { grid-template-columns: 1fr; }
  .checklist-grid { grid-template-columns: 1fr; }
  .admin-page { padding: 16px; }
  .stats-grid { grid-template-columns: repeat(2, 1fr); }
  .form-page { margin: 20px auto; }
}
@media (max-width: 480px) {
  .stats-grid { grid-template-columns: 1fr; }
}