:root {
  --bg: #f4f7fb;
  --panel: #ffffff;
  --line: #d7dfeb;
  --text: #1e293b;
  --muted: #64748b;
  --primary: #2563eb;
  --primary-dark: #1d4ed8;
  --danger: #dc2626;
  --success: #16a34a;
  --shadow: 0 18px 40px rgba(15, 23, 42, 0.08);
  --radius: 12px;
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; font-family: Inter, Arial, sans-serif; background: var(--bg); color: var(--text); }
a { color: inherit; text-decoration: none; }
[hidden] { display: none !important; }
img { max-width: 100%; display: block; }
button, input, textarea, select { font: inherit; }

.container { width: min(1180px, calc(100% - 32px)); margin: 0 auto; }
.page-section { padding: 32px 0 56px; }
.topbar { background: #263063; color: #fff; position: sticky; top: 0; z-index: 10; box-shadow: 0 8px 24px rgba(15, 23, 42, 0.28); }
.topbar-inner { display: flex; align-items: center; justify-content: space-between; gap: 24px; padding: 18px 0; }
.brand { font-size: 1.25rem; font-weight: 800; color: #fff; }
.subtitle { color: rgba(255,255,255,0.72); font-size: .95rem; margin-top: 4px; }
.topbar-nav { display: flex; gap: 12px; flex-wrap: wrap; }
.topbar-nav a { color: #fff; opacity: .92; padding: 10px 14px; border-radius: 999px; background: rgba(255,255,255,0.08); }
.hero-card, .admin-form, .auth-card, .viewer-card, .accordion-card, .card, .stat-card, .empty-state { background: var(--panel); border: 1px solid var(--line); border-radius: var(--radius); box-shadow: var(--shadow); }
.hero-card { padding: 20px; display: flex; align-items: center; justify-content: space-between; gap: 24px; margin-bottom: 28px; }
.hero-card.slim { display: block; }
.eyebrow { display: inline-flex; font-size: .82rem; font-weight: 700; letter-spacing: .04em; text-transform: uppercase; color: var(--primary); margin-bottom: 8px; }
h1, h2, h3 { margin: 0 0 10px; line-height: 1.15; }
p { margin: 0; line-height: 1.6; color: var(--muted); }
.section-header { display: flex; justify-content: space-between; gap: 20px; align-items: end; margin-bottom: 18px; }
.card-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); gap: 16px; }
.card-body, .card-footer, .accordion-header, .accordion-body, .stat-card, .empty-state { padding: 22px; }
.course-card .card-footer { border-top: 1px solid var(--line); }
.course-card .card-body { padding: 16px; }
.course-card .card-footer { padding: 14px 16px; }
.course-thumb { display: block; width: 100%; max-width: 340px; max-height: 240px; aspect-ratio: 16 / 9; overflow: hidden; border: 1px solid var(--line); border-radius: 8px; background: #eef2f7; margin-bottom: 12px; box-shadow: 0 8px 18px rgba(15, 23, 42, 0.05); }
.course-thumb img { width: 100%; height: 100%; object-fit: cover; }
.course-card h3 { font-size: 1rem; margin-bottom: 8px; }
.course-card p { font-size: .94rem; line-height: 1.5; }
.course-card .pill { margin-bottom: 8px; }
.course-card .meta-line { font-size: .9rem; gap: 10px; }
.course-card .button { padding: 10px 14px; }
.course-hero-thumb { margin-bottom: 20px; overflow: hidden; border-radius: 10px; border: 1px solid var(--line); background: #eef2f7; }
.course-hero-thumb img { width: 100%; max-height: 320px; object-fit: cover; }
.spaced, .meta-line, .actions-cell, .field-row, .form-actions, .viewer-controls, .audio-box { display: flex; gap: 12px; align-items: center; }
.spaced { justify-content: space-between; }
.meta-line { color: var(--muted); flex-wrap: wrap; }
.button { border: none; cursor: pointer; padding: 12px 18px; border-radius: 8px; font-weight: 700; display: inline-flex; align-items: center; justify-content: center; gap: 8px; }
.button.small { padding: 8px 12px; font-size: .92rem; }
.button.full { width: 100%; }
.button-primary { background: var(--primary); color: #fff; }
.button-primary:hover { background: var(--primary-dark); }
.button-secondary { background: #e8eefb; color: var(--text); }
.button-danger { background: #fee2e2; color: var(--danger); }
.pill { display: inline-flex; align-items: center; font-size: .78rem; padding: 6px 10px; background: #dbeafe; color: #1d4ed8; border-radius: 8px; font-weight: 700; margin-bottom: 12px; }
.accordion-list, .admin-section { display: grid; gap: 18px; }
.accordion-summary { list-style: none; cursor: pointer; display: flex; justify-content: space-between; gap: 20px; align-items: center; }
.accordion-summary::-webkit-details-marker { display: none; }
.accordion-panel { padding-top: 0; }
.accordion-chevron { width: 12px; height: 12px; border-right: 2px solid var(--muted); border-bottom: 2px solid var(--muted); transform: rotate(45deg); transition: transform .2s ease; flex: 0 0 auto; margin-left: 4px; }
.course-tree[open] .accordion-chevron { transform: rotate(225deg); }
.lesson-list { display: grid; gap: 12px; }
.course-tree .lesson-list { padding-left: 18px; border-left: 2px solid #dbeafe; margin-left: 8px; }
.lesson-item { border: 1px solid var(--line); border-radius: 10px; padding: 16px; display: flex; justify-content: space-between; gap: 16px; align-items: center; }
.viewer-card { padding: 20px; display: grid; gap: 18px; }
.viewer-frame-wrap { position: relative; }
.viewer-expand-button { position: absolute; top: 12px; right: 12px; z-index: 2; }
.viewer-frame { background: #eef2f7; border-radius: 18px; min-height: 320px; display: flex; align-items: center; justify-content: center; padding: 12px; }
.viewer-frame img { max-height: 70vh; width: auto; border-radius: 10px; box-shadow: 0 12px 24px rgba(0,0,0,.08); }
.viewer-video { width: min(100%, 1080px); max-height: 72vh; border-radius: 12px; background: #000; box-shadow: 0 16px 32px rgba(15, 23, 42, .22); }
.viewer-controls { flex-direction: column; justify-content: space-between; flex-wrap: wrap; }
.viewer-nav-row { display: flex; gap: 12px; }
.viewer-nav-row .button { flex: 1 1 0; white-space: nowrap; }
.viewer-status { display: grid; gap: 4px; text-align: center; }
.nav-icon { font-size: 1rem; line-height: 1; }
.slide-content-box { border: 1px solid var(--line); border-radius: 10px; padding: 20px; background: #fcfdff; overflow: hidden; display: grid; gap: 14px; }
.slide-text { margin-top: 0px; line-height: 1.8; font-size: 1.02rem; }
.slide-text.ql-editor { padding: 0; min-height: 0; }
.slide-text.ql-editor p,
.slide-text.ql-editor ol,
.slide-text.ql-editor ul,
.slide-text.ql-editor pre,
.slide-text.ql-editor blockquote,
.slide-text.ql-editor h1,
.slide-text.ql-editor h2,
.slide-text.ql-editor h3,
.slide-text.ql-editor h4,
.slide-text.ql-editor h5,
.slide-text.ql-editor h6 { color: inherit; }
.audio-box { display: grid; gap: 12px; align-items: stretch; margin-top: 0; }
.slide-audio-control { display: block; width: 100%; max-width: 520px; }
.thumb-track { display: grid; grid-template-columns: repeat(auto-fit, minmax(110px, 1fr)); gap: 12px; }
.thumb-button { border: 2px solid transparent; background: #fff; border-radius: 8px; padding: 8px; cursor: pointer; display: grid; gap: 8px; }
.thumb-button.is-active { border-color: var(--primary); box-shadow: 0 10px 24px rgba(37, 99, 235, .18); }
.thumb-button img { width: 100%; aspect-ratio: 16/9; object-fit: cover; border-radius: 6px; }
.modal-open { overflow: hidden; }
.image-modal[hidden] { display: none; }
.image-modal { position: fixed; inset: 0; z-index: 1000; display: grid; place-items: center; padding: 20px; }
.image-modal-backdrop { position: absolute; inset: 0; background: rgba(15, 23, 42, 0.82); }
.image-modal-dialog { position: relative; z-index: 1; width: min(96vw, 1200px); max-height: 92vh; background: var(--panel); border: 1px solid var(--line); border-radius: 12px; box-shadow: var(--shadow); display: grid; overflow: hidden; }
.image-modal-header { display: flex; justify-content: space-between; align-items: center; gap: 12px; padding: 14px 16px; border-bottom: 1px solid var(--line); }
.image-modal-body { padding: 12px; display: flex; align-items: center; justify-content: center; background: #0f172a; }
.image-modal-body img { max-width: 100%; max-height: calc(92vh - 74px); object-fit: contain; border-radius: 8px; }
.breadcrumb { display: flex; gap: 8px; color: var(--muted); margin-bottom: 18px; flex-wrap: wrap; }
.flash { padding: 14px 18px; border-radius: 14px; margin-bottom: 18px; border: 1px solid transparent; }
.flash-success { background: #dcfce7; border-color: #86efac; color: #166534; }
.flash-error { background: #fee2e2; border-color: #fca5a5; color: #991b1b; }
.site-footer { position: relative; z-index: 1; margin-top: 32px; background: #263063; color: rgba(255,255,255,0.86); font-size: 14px; }
.site-footer-inner { display: grid; gap: 14px; padding: 24px 0; }
.site-footer-main { display: grid; grid-template-columns: minmax(0, 1.3fr) minmax(0, 1fr) auto; gap: 18px; align-items: center; }
.site-footer-brand strong { display: block; margin-bottom: 6px; color: #fff; font-size: 14px; }
.site-footer-brand p { color: rgba(255,255,255,0.72); }
.site-footer-meta { display: flex; gap: 16px; flex-wrap: wrap; }
.site-footer-meta a { color: #93c5fd; }
.site-footer-whatsapp { display: flex; justify-content: flex-end; }
.whatsapp-link { display: inline-flex; align-items: center; gap: 10px; padding: 12px 16px; border-radius: 999px; background: #16a34a; color: #fff; font-weight: 700; white-space: nowrap; font-size: 14px; }
.whatsapp-link:hover { background: #15803d; }
.whatsapp-icon { display: inline-flex; width: 22px; height: 22px; }
.whatsapp-icon svg { width: 100%; height: 100%; }
.site-footer-copy { font-size: 14px; color: rgba(255,255,255,0.64); }
.auth-wrapper { display: flex; justify-content: center; }
.auth-card { width: min(100%, 460px); padding: 28px; display: grid; gap: 16px; }
.auth-card.wide, .admin-form { width: min(100%, 860px); }
.form-page .admin-form { padding: 28px; display: grid; gap: 18px; }
.field { display: grid; gap: 8px; }
.field > span { font-weight: 700; }
.field input, .field textarea, .field select { padding: 13px 14px; border: 1px solid var(--line); border-radius: 8px; background: #fff; }
.field textarea.is-hidden { display: none; }
.quill-field .ql-toolbar,
.quill-field .ql-container { background: #fff; border-color: var(--line); }
.quill-field .ql-toolbar { border-top-left-radius: 8px; border-top-right-radius: 8px; }
.quill-field .ql-container { min-height: 260px; border-bottom-left-radius: 8px; border-bottom-right-radius: 8px; }
.quill-field .ql-editor { min-height: 220px; }
.checkbox-field { display: flex; align-items: center; gap: 10px; padding-top: 28px; }
.checkbox-field input { width: 18px; height: 18px; }
.stats-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(180px, 1fr)); gap: 16px; margin-bottom: 24px; }
.stat-card { text-align: center; }
.stat-card span { color: var(--muted); display: block; margin-bottom: 10px; }
.stat-card strong { font-size: 2rem; }
.tree-grid { display: grid; gap: 18px; }
.tree-card { background: var(--panel); border: 1px solid var(--line); border-radius: var(--radius); box-shadow: var(--shadow); }
.tree-card-body { padding: 24px; display: grid; gap: 18px; }
.tree-header { display: flex; justify-content: space-between; gap: 20px; align-items: flex-start; }
.tree-course-summary { display: flex; align-items: flex-start; gap: 18px; }
.tree-course-thumb { width: 140px; min-width: 140px; aspect-ratio: 16 / 9; overflow: hidden; border-radius: 10px; border: 1px solid var(--line); background: #eef2f7; }
.tree-course-thumb img { width: 100%; height: 100%; object-fit: cover; }
.tree-actions { display: flex; gap: 10px; flex-wrap: wrap; justify-content: flex-end; }
.tree-meta { row-gap: 6px; }
.tree-empty { padding: 16px 18px; border: 1px dashed var(--line); border-radius: 8px; color: var(--muted); background: #fcfdff; }
.tree-node .tree-body { display: grid; gap: 14px; }
.tree-branch { padding-left: 16px; border-left: 2px solid #dbeafe; margin-left: 6px; }
.tree-leaf { align-items: stretch; }
.tree-leaf.is-focused { border-color: #93c5fd; box-shadow: 0 12px 24px rgba(37, 99, 235, 0.12); background: #f8fbff; }
.slide-tree-list { display: grid; gap: 10px; margin-top: 14px; }
.slide-tree-item { display: flex; justify-content: space-between; gap: 16px; align-items: center; padding: 12px 14px; border: 1px solid var(--line); border-radius: 10px; background: #fff; }
.tree-nested-empty { margin-top: 14px; padding: 12px 14px; }
.table-wrap { overflow: auto; background: var(--panel); border: 1px solid var(--line); border-radius: var(--radius); box-shadow: var(--shadow); }
.admin-table { width: 100%; border-collapse: collapse; min-width: 760px; }
.admin-table th, .admin-table td { padding: 16px; border-bottom: 1px solid var(--line); text-align: left; vertical-align: top; }
.admin-table th { background: #f8fafc; font-size: .92rem; color: var(--muted); }
.actions-cell { flex-wrap: wrap; }
.media-preview img { max-width: 320px; border-radius: 8px; border: 1px solid var(--line); }
.video-preview video { width: min(100%, 520px); border-radius: 8px; border: 1px solid var(--line); background: #000; }
.audio-preview audio { width: min(100%, 420px); }
.muted { color: var(--muted); }
.empty-state { padding: 28px; text-align: center; }

@media (max-width: 780px) {
  .hero-card, .section-header, .topbar-inner, .viewer-controls, .field-row, .form-actions, .lesson-item, .tree-header, .tree-course-summary, .slide-tree-item, .site-footer-meta { flex-direction: column; align-items: stretch; }
  .topbar-nav { width: 100%; }
  .topbar-nav a { text-align: center; flex: 1 1 auto; }
  .container { width: min(100% - 20px, 1180px); }
  .tree-actions { justify-content: stretch; }
  .tree-course-thumb { width: 100%; min-width: 0; }
  .tree-branch { padding-left: 10px; margin-left: 0; }
  .site-footer-main { grid-template-columns: 1fr; }
  .site-footer-whatsapp { justify-content: flex-start; }
  .public-page .page-section, .lesson-page .page-section { padding: 12px 0 24px; }
  .public-page .topbar-inner, .lesson-page .topbar-inner { padding: 10px 0; gap: 6px; }
  .public-page .brand, .lesson-page .brand { font-size: .98rem; }
  .public-page .subtitle, .lesson-page .subtitle { display: none; }
  .public-page .hero-card, .lesson-page .hero-card { padding: 14px; gap: 10px; margin-bottom: 12px; }
  .public-page .hero-card h1, .lesson-page .hero-card h1 { font-size: 1.18rem; line-height: 1.2; margin-bottom: 4px; }
  .public-page .hero-card p, .lesson-page .hero-card p { font-size: .92rem; line-height: 1.45; }
  .public-page .section-header, .lesson-page .section-header { gap: 6px; margin-bottom: 10px; }
  .public-page .section-header h2, .lesson-page .section-header h2 { font-size: 1.02rem; margin-bottom: 2px; }
  .public-page .section-header p, .lesson-page .section-header p { font-size: .88rem; line-height: 1.4; }
  .public-page .breadcrumb, .lesson-page .breadcrumb { margin-bottom: 10px; font-size: .82rem; gap: 5px; }
  .public-page .eyebrow, .lesson-page .eyebrow { margin-bottom: 4px; font-size: .72rem; }
  .public-page .course-hero-thumb, .lesson-page .course-hero-thumb { margin-bottom: 10px; }
  .public-page .course-hero-thumb img, .lesson-page .course-hero-thumb img { max-height: 140px; }
  .public-page .accordion-header, .lesson-page .accordion-header { padding: 14px; }
  .public-page .accordion-body, .lesson-page .accordion-body { padding: 14px; }
  .public-page .lesson-item, .lesson-page .lesson-item { padding: 10px 12px; gap: 8px; }
  .lesson-page .viewer-controls { gap: 10px; }
  .lesson-page .viewer-nav-row { gap: 8px; }
  .lesson-page .viewer-nav-row .button { padding: 10px 12px; font-size: .9rem; }
  .lesson-page .viewer-status { font-size: .88rem; }
  .lesson-page .slide-content-box { padding: 14px; }
  .lesson-page .audio-box { gap: 10px; }
  .lesson-page .slide-audio-control { max-width: 100%; min-width: 0; }
  .lesson-page .audio-box .muted { line-height: 1.4; }
  .lesson-page .viewer-expand-button { top: 8px; right: 8px; padding: 8px 10px; font-size: .85rem; }
  .lesson-page .image-modal { padding: 10px; }
  .lesson-page .image-modal-header { padding: 10px 12px; }
  .lesson-page .image-modal-body { padding: 8px; }
  .public-page .course-card p, .lesson-page .course-card p {
    display: -webkit-box;
    line-clamp: 2;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
  }
}

@media (max-width: 780px) and (orientation: portrait) {
  .lesson-page .container { width: min(100% - 10px, 1180px); }
  .lesson-page .viewer-card { padding: 10px; gap: 10px; }
  .lesson-page .viewer-frame { padding: 4px; border-radius: 12px; min-height: 240px; }
  .lesson-page .viewer-frame img { width: 100%; max-width: 100%; max-height: 72vh; border-radius: 8px; }
}

@media (max-width: 980px) and (orientation: landscape) {
  .public-page .page-section, .lesson-page .page-section { padding: 12px 0 24px; }
  .public-page .topbar-inner, .lesson-page .topbar-inner { padding: 10px 0; gap: 6px; }
  .public-page .brand, .lesson-page .brand { font-size: .98rem; }
  .public-page .subtitle, .lesson-page .subtitle { display: none; }
  .public-page .hero-card, .lesson-page .hero-card { padding: 14px; gap: 10px; margin-bottom: 12px; }
  .public-page .hero-card.slim, .lesson-page .hero-card.slim { padding: 10px 12px; gap: 6px; margin-bottom: 8px; }
  .public-page .hero-card h1, .lesson-page .hero-card h1 { font-size: 1.18rem; line-height: 1.2; margin-bottom: 4px; }
  .public-page .hero-card.slim h1, .lesson-page .hero-card.slim h1 { font-size: 1rem; line-height: 1.15; margin-bottom: 2px; }
  .public-page .hero-card p, .lesson-page .hero-card p { font-size: .92rem; line-height: 1.45; }
  .public-page .hero-card.slim p, .lesson-page .hero-card.slim p { font-size: .84rem; line-height: 1.3; }
  .public-page .section-header, .lesson-page .section-header { gap: 6px; margin-bottom: 10px; }
  .public-page .section-header h2, .lesson-page .section-header h2 { font-size: 1.02rem; margin-bottom: 2px; }
  .public-page .section-header p, .lesson-page .section-header p { font-size: .88rem; line-height: 1.4; }
  .public-page .breadcrumb, .lesson-page .breadcrumb { margin-bottom: 10px; font-size: .82rem; gap: 5px; }
  .public-page .eyebrow, .lesson-page .eyebrow { margin-bottom: 4px; font-size: .72rem; }
  .public-page .hero-card.slim .eyebrow, .lesson-page .hero-card.slim .eyebrow { margin-bottom: 2px; font-size: .68rem; }
  .public-page .course-hero-thumb, .lesson-page .course-hero-thumb { margin-bottom: 10px; }
  .public-page .course-hero-thumb img, .lesson-page .course-hero-thumb img { max-height: 96px; }
  .public-page .accordion-header, .lesson-page .accordion-header { padding: 14px; }
  .public-page .accordion-body, .lesson-page .accordion-body { padding: 14px; }
  .public-page .lesson-item, .lesson-page .lesson-item { padding: 10px 12px; gap: 8px; }
  .lesson-page .viewer-controls { gap: 10px; }
  .lesson-page .viewer-nav-row { gap: 8px; }
  .lesson-page .viewer-nav-row .button { padding: 10px 12px; font-size: .9rem; }
  .lesson-page .viewer-status { font-size: .88rem; }
  .lesson-page .viewer-expand-button { top: 8px; right: 8px; padding: 8px 10px; font-size: .85rem; }
  .lesson-page .image-modal { padding: 10px; }
  .lesson-page .image-modal-header { padding: 10px 12px; }
  .lesson-page .image-modal-body { padding: 8px; }
  .public-page .course-card p, .lesson-page .course-card p {
    display: -webkit-box;
    line-clamp: 2;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
  }
}