:root {
  --bg: #ffffff; --fg: #0f172a; --muted: #64748b; --border: #e2e8f0;
  --card: #f8fafc; --accent: #6366f1; --accent-fg: #ffffff;
  --discord: #5865f2; --danger: #dc2626; --ok: #16a34a;
  --shadow: 0 1px 3px rgba(0,0,0,.08), 0 8px 24px rgba(0,0,0,.06);
}
:root[data-theme="dark"] {
  --bg: #0b1120; --fg: #e2e8f0; --muted: #94a3b8; --border: #1e293b;
  --card: #111827; --accent: #818cf8; --accent-fg: #0b1120;
  --shadow: 0 1px 3px rgba(0,0,0,.4), 0 8px 24px rgba(0,0,0,.5);
}
* { box-sizing: border-box; margin: 0; padding: 0; }
body {
  font-family: ui-monospace, "SF Mono", "JetBrains Mono", Menlo, Consolas, monospace;
  background: var(--bg); color: var(--fg); min-height: 100vh;
  display: flex; flex-direction: column;
  transition: background .25s ease, color .25s ease;
}
a { color: var(--accent); }

.topbar { display: flex; align-items: center; justify-content: space-between; padding: 1rem 1.5rem; border-bottom: 1px solid var(--border); }
.brand { font-weight: 700; letter-spacing: -.02em; }
.brand a { color: inherit; text-decoration: none; }
.topbar .right { display: flex; gap: .5rem; align-items: center; }
.who { color: var(--muted); font-size: .85rem; }

.icon-btn { background: var(--card); border: 1px solid var(--border); color: var(--fg);
  width: 40px; height: 40px; border-radius: 10px; cursor: pointer; font-size: 1.1rem;
  display: grid; place-items: center; transition: transform .15s, border-color .15s; }
.icon-btn:hover { transform: translateY(-1px); border-color: var(--accent); }

.center { flex: 1; display: flex; flex-direction: column; align-items: center; justify-content: center; text-align: center; gap: 1.75rem; padding: 2rem 1.25rem; }
.wrap { width: 100%; max-width: 900px; margin: 0 auto; padding: 2rem 1.25rem; flex: 1; }

.hero h1 { font-size: clamp(2.2rem, 7vw, 4rem); letter-spacing: -.04em; }
.hero h1 .cursor { display: inline-block; width: .55ch; background: var(--accent); animation: blink 1.1s steps(1) infinite; margin-left: .05em; }
@keyframes blink { 50% { opacity: 0; } }
.hero p { color: var(--muted); margin-top: .5rem; }

.actions { display: flex; flex-wrap: wrap; gap: .75rem; justify-content: center; }
.btn { display: inline-flex; align-items: center; gap: .55rem; padding: .7rem 1.15rem;
  border-radius: 10px; border: 1px solid var(--border); background: var(--card); color: var(--fg);
  font: inherit; font-size: .95rem; text-decoration: none; cursor: pointer;
  transition: transform .15s, border-color .15s, background .15s; }
.btn:hover { transform: translateY(-1px); border-color: var(--accent); }
.btn svg { width: 18px; height: 18px; }
.btn-primary { background: var(--accent); color: var(--accent-fg); border-color: var(--accent); }
.btn-discord { background: var(--discord); color: #fff; border-color: var(--discord); }
.btn-block { width: 100%; justify-content: center; }
.btn-sm { padding: .45rem .7rem; font-size: .82rem; }

.card { background: var(--card); border: 1px solid var(--border); border-radius: 16px;
  box-shadow: var(--shadow); padding: 2rem; width: 100%; max-width: 400px; text-align: left; }
.card h2 { margin-bottom: 1.25rem; letter-spacing: -.02em; }
.field { margin-bottom: 1rem; display: flex; flex-direction: column; gap: .35rem; }
.field label { font-size: .8rem; color: var(--muted); }
.field input, .field textarea, .field select { font: inherit; padding: .6rem .7rem; border-radius: 8px;
  border: 1px solid var(--border); background: var(--bg); color: var(--fg); width: 100%; }
.field textarea { min-height: 120px; resize: vertical; }
.form-error { color: var(--danger); font-size: .85rem; min-height: 1.2em; }
.form-ok { color: var(--ok); font-size: .85rem; min-height: 1.2em; }
.muted-link { color: var(--muted); font-size: .85rem; text-align: center; margin-top: 1rem; }

h2.section { letter-spacing: -.02em; margin-bottom: 1.25rem; }
.grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(240px, 1fr)); gap: 1rem; }
.tile { display: block; text-decoration: none; color: inherit; background: var(--card);
  border: 1px solid var(--border); border-radius: 14px; padding: 1.25rem; transition: transform .15s, border-color .15s; }
.tile:hover { transform: translateY(-2px); border-color: var(--accent); }
.tile h3 { letter-spacing: -.02em; margin-bottom: .35rem; }
.tile p { color: var(--muted); font-size: .88rem; }
.badge { display: inline-block; font-size: .7rem; padding: .15rem .5rem; border-radius: 999px;
  border: 1px solid var(--border); color: var(--muted); margin-top: .6rem; }

.lesson-list { list-style: none; display: flex; flex-direction: column; gap: .5rem; }
.lesson-list a { display: flex; justify-content: space-between; align-items: center; gap: .5rem;
  text-decoration: none; color: inherit; background: var(--card); border: 1px solid var(--border);
  border-radius: 10px; padding: .8rem 1rem; transition: border-color .15s; }
.lesson-list a:hover { border-color: var(--accent); }

.video-embed { position: relative; width: 100%; aspect-ratio: 16/9; border-radius: 12px; overflow: hidden; border: 1px solid var(--border); margin: 1.25rem 0; }
.video-embed iframe { position: absolute; inset: 0; width: 100%; height: 100%; border: 0; }

.prose { line-height: 1.7; }
.prose h1, .prose h2, .prose h3 { margin: 1.4rem 0 .6rem; letter-spacing: -.02em; }
.prose p { margin: .8rem 0; }
.prose ul, .prose ol { margin: .8rem 0 .8rem 1.4rem; }
.prose code { background: var(--card); border: 1px solid var(--border); border-radius: 5px; padding: .1rem .35rem; font-size: .9em; }
.prose pre { background: var(--card); border: 1px solid var(--border); border-radius: 10px; padding: 1rem; overflow-x: auto; margin: 1rem 0; }
.prose pre code { border: 0; padding: 0; background: none; }

.resources { list-style: none; display: flex; flex-direction: column; gap: .5rem; margin-top: 1rem; }
.resources a { display: inline-flex; gap: .5rem; align-items: center; text-decoration: none;
  background: var(--card); border: 1px solid var(--border); border-radius: 8px; padding: .6rem .9rem; color: inherit; }

footer { text-align: center; padding: 1.25rem; color: var(--muted); font-size: .8rem; border-top: 1px solid var(--border); }
footer a { color: var(--muted); }

.admin-course { border: 1px solid var(--border); border-radius: 12px; padding: 1rem 1.25rem; margin-bottom: 1rem; background: var(--card); }
.row { display: flex; gap: .5rem; flex-wrap: wrap; align-items: center; }

/* progreso */
.progress-bar { height: 8px; border-radius: 999px; background: var(--card); border: 1px solid var(--border); overflow: hidden; }
.progress-fill { height: 100%; background: var(--ok); transition: width .3s ease; }

/* módulos (vista alumno) */
.module { margin-bottom: 1.5rem; }
.module-title { letter-spacing: -.02em; margin-bottom: .6rem; padding-bottom: .4rem; border-bottom: 1px solid var(--border); }

/* botón completar lección */
.complete-toggle { display: inline-flex; align-items: center; gap: .5rem; margin: 1rem 0; }
.btn-done { background: var(--ok); color: #fff; border-color: var(--ok); }

/* admin: módulos y lecciones anidadas */
.admin-module { border-left: 2px solid var(--border); margin: .6rem 0 .6rem .25rem; padding-left: .85rem; }
.admin-lesson { display: flex; align-items: center; gap: .5rem; justify-content: space-between; padding: .35rem 0; flex-wrap: wrap; }
.mini { background: none; border: 1px solid var(--border); color: var(--muted); border-radius: 6px; padding: .2rem .45rem; cursor: pointer; font: inherit; font-size: .78rem; }
.mini:hover { border-color: var(--accent); color: var(--fg); }
.mini.danger:hover { border-color: var(--danger); color: var(--danger); }
.tag-draft { font-size: .68rem; color: var(--danger); border: 1px solid var(--danger); border-radius: 999px; padding: .05rem .4rem; }
.inline-form { display: flex; gap: .4rem; flex-wrap: wrap; align-items: center; margin: .4rem 0; }
.inline-form input, .inline-form select { padding: .4rem .55rem; }