/* ============================================================
   Curso Completo de Inglés — A1 a C2
   Hoja de estilos principal
   ============================================================ */

:root {
  --bg: #f6f7fb;
  --bg-elev: #ffffff;
  --bg-soft: #eef1f8;
  --text: #16192a;
  --text-soft: #5b6178;
  --border: #dfe3ee;
  --accent: #3b5bdb;
  --accent-soft: #e7ecfd;
  --accent-text: #2b45a8;
  --green: #178f5b;
  --green-soft: #e2f6ec;
  --red: #c62b3f;
  --red-soft: #fdeaec;
  --amber: #a4700a;
  --amber-soft: #fdf3dd;
  --shadow: 0 1px 2px rgba(18,22,40,.06), 0 8px 24px rgba(18,22,40,.06);
  --radius: 14px;
  --sidebar-w: 300px;
  --topbar-h: 62px;
  --mono: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Inter, Roboto, Helvetica, Arial, sans-serif;
}

html[data-theme="dark"] {
  --bg: #0e1017;
  --bg-elev: #161a25;
  --bg-soft: #1d2230;
  --text: #e8eaf2;
  --text-soft: #9aa2b8;
  --border: #262c3c;
  --accent: #7d97ff;
  --accent-soft: #1c2440;
  --accent-text: #a9bbff;
  --green: #4ad392;
  --green-soft: #12301f;
  --red: #ff8b98;
  --red-soft: #34161c;
  --amber: #e8bd63;
  --amber-soft: #2f2610;
  --shadow: 0 1px 2px rgba(0,0,0,.4), 0 8px 24px rgba(0,0,0,.35);
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; scroll-padding-top: calc(var(--topbar-h) + 16px); }

body {
  margin: 0;
  font-family: var(--sans);
  background: var(--bg);
  color: var(--text);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

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

/* ---------------- Topbar ---------------- */

.topbar {
  position: sticky;
  top: 0;
  z-index: 60;
  height: var(--topbar-h);
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 0 16px;
  background: color-mix(in srgb, var(--bg-elev) 88%, transparent);
  backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid var(--border);
}

.brand { display: flex; align-items: center; gap: 10px; color: var(--text); text-decoration: none; flex-shrink: 0; }
.brand:hover { text-decoration: none; }
.brand-mark {
  display: grid; place-items: center;
  width: 36px; height: 36px; border-radius: 10px;
  background: var(--accent); color: #fff;
  font-weight: 800; font-size: 14px; letter-spacing: .5px;
}
.brand-text { display: flex; flex-direction: column; font-weight: 700; font-size: 15px; line-height: 1.15; }
.brand-text small { font-weight: 500; font-size: 11px; color: var(--text-soft); letter-spacing: .06em; }

.icon-btn {
  border: 1px solid var(--border);
  background: var(--bg-elev);
  color: var(--text);
  width: 38px; height: 38px;
  border-radius: 10px;
  cursor: pointer;
  font-size: 16px;
  display: grid; place-items: center;
  flex-shrink: 0;
}
.icon-btn:hover { background: var(--bg-soft); }
.menu-toggle { display: none; }

/* Botón de tema: icono SVG que hereda el color del texto */
.theme-btn { color: var(--text-soft); }
.theme-btn:hover { color: var(--accent); border-color: var(--accent); }
.theme-btn svg { width: 19px; height: 19px; display: block; transition: transform .3s ease; }
.theme-btn:hover svg { transform: rotate(-18deg); }

.search-wrap { position: relative; flex: 1; max-width: 520px; margin-left: auto; }
#search {
  width: 100%;
  height: 40px;
  padding: 0 14px;
  border-radius: 10px;
  border: 1px solid var(--border);
  background: var(--bg-soft);
  color: var(--text);
  font-size: 14px;
  font-family: inherit;
}
#search:focus { outline: 2px solid var(--accent); outline-offset: 1px; background: var(--bg-elev); }

.search-results {
  position: absolute;
  top: 46px; left: 0; right: 0;
  max-height: 60vh; overflow-y: auto;
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: 12px;
  box-shadow: var(--shadow);
  padding: 6px;
  z-index: 80;
}
.search-results .sr-item {
  display: block; padding: 9px 11px; border-radius: 8px;
  color: var(--text); font-size: 14px; cursor: pointer;
}
.search-results .sr-item:hover { background: var(--accent-soft); text-decoration: none; }
.search-results .sr-item .sr-level {
  display: inline-block; font-size: 10px; font-weight: 700;
  background: var(--accent-soft); color: var(--accent-text);
  padding: 1px 6px; border-radius: 20px; margin-right: 8px;
}
.search-results .sr-sub { display: block; font-size: 12px; color: var(--text-soft); }
.search-results .sr-empty { padding: 14px; color: var(--text-soft); font-size: 14px; text-align: center; }

/* ---------------- Layout ---------------- */

.layout { display: flex; align-items: flex-start; }

.sidebar {
  position: sticky;
  top: var(--topbar-h);
  width: var(--sidebar-w);
  flex-shrink: 0;
  height: calc(100vh - var(--topbar-h));
  overflow-y: auto;
  border-right: 1px solid var(--border);
  padding: 18px 14px 40px;
  background: var(--bg-elev);
}

.content {
  flex: 1;
  min-width: 0;
  padding: 34px clamp(18px, 4vw, 56px) 120px;
  max-width: 980px;
  margin: 0 auto;
}

.overlay {
  display: none;
  position: fixed; inset: 0;
  background: rgba(0,0,0,.45);
  z-index: 55;
}
.overlay.show { display: block; }

/* ---------------- Sidebar nav ---------------- */

.level-nav { display: flex; flex-direction: column; gap: 4px; margin-bottom: 18px; }

.nav-title {
  font-size: 11px; text-transform: uppercase; letter-spacing: .1em;
  color: var(--text-soft); font-weight: 700; margin: 4px 8px 8px;
}

.level-link {
  display: flex; align-items: center; gap: 10px;
  padding: 9px 11px; border-radius: 10px;
  color: var(--text); font-size: 14px; font-weight: 600;
  cursor: pointer;
}
.level-link:hover { background: var(--bg-soft); text-decoration: none; }
.level-link.active { background: var(--accent-soft); color: var(--accent-text); }
.level-badge {
  font-size: 11px; font-weight: 800;
  background: var(--bg-soft); color: var(--text-soft);
  border: 1px solid var(--border);
  padding: 2px 7px; border-radius: 20px; min-width: 34px; text-align: center;
}
.level-link.active .level-badge { background: var(--accent); color: #fff; border-color: transparent; }
.icon-badge { display: grid; place-items: center; padding: 3px 0; }
.icon-badge svg { width: 16px; height: 16px; display: block; }
.level-link small { margin-left: auto; font-size: 11px; color: var(--text-soft); font-weight: 500; }

.progress-box {
  background: var(--bg-soft);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 12px;
  margin-bottom: 18px;
}
.progress-label { font-size: 12px; font-weight: 600; color: var(--text-soft); display: flex; justify-content: space-between; margin-bottom: 8px; }
.progress-label span { color: var(--accent-text); font-weight: 800; }
.progress-bar { height: 7px; background: var(--border); border-radius: 20px; overflow: hidden; }
.progress-fill { height: 100%; width: 0%; background: var(--accent); border-radius: 20px; transition: width .3s ease; }
.reset-btn {
  margin-top: 10px; width: 100%;
  background: transparent; border: 1px solid var(--border);
  color: var(--text-soft); border-radius: 8px; padding: 5px;
  font-size: 11.5px; cursor: pointer; font-family: inherit;
}
.reset-btn:hover { color: var(--red); border-color: var(--red); }

.toc-title {
  font-size: 11px; text-transform: uppercase; letter-spacing: .1em;
  color: var(--text-soft); font-weight: 700; margin: 0 8px 8px;
}
.toc-link {
  display: block; padding: 6px 10px; border-radius: 8px;
  font-size: 13px; color: var(--text-soft); cursor: pointer;
  border-left: 2px solid transparent;
}
.toc-link:hover { background: var(--bg-soft); color: var(--text); text-decoration: none; }
.toc-link.active { color: var(--accent-text); border-left-color: var(--accent); background: var(--accent-soft); font-weight: 600; }
.toc-link.done::after { content: " ✓"; color: var(--green); font-weight: 700; }
.toc-group { font-size: 11px; font-weight: 800; color: var(--text); margin: 14px 10px 4px; text-transform: uppercase; letter-spacing: .06em; }

/* ---------------- Hero / portada ---------------- */

.hero {
  background: linear-gradient(135deg, var(--accent) 0%, #6b3fd4 100%);
  color: #fff;
  border-radius: 20px;
  padding: 42px 38px;
  margin-bottom: 30px;
  box-shadow: var(--shadow);
}
.hero h1 { margin: 0 0 10px; font-size: clamp(26px, 4vw, 40px); line-height: 1.15; letter-spacing: -.02em; }
.hero p { margin: 0; font-size: 16px; opacity: .93; max-width: 640px; }
.hero-stats { display: flex; flex-wrap: wrap; gap: 26px; margin-top: 26px; }
.hero-stats div { line-height: 1.2; }
.hero-stats strong { display: block; font-size: 26px; font-weight: 800; }
.hero-stats span { font-size: 12px; opacity: .85; text-transform: uppercase; letter-spacing: .08em; }

.cards { display: grid; grid-template-columns: repeat(auto-fill, minmax(250px, 1fr)); gap: 16px; margin: 22px 0 36px; }
.card {
  background: var(--bg-elev); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 20px; cursor: pointer;
  transition: transform .15s ease, box-shadow .15s ease;
  color: var(--text);
}
.card:hover { transform: translateY(-3px); box-shadow: var(--shadow); text-decoration: none; }
.card h3 { margin: 0 0 4px; font-size: 17px; display: flex; align-items: center; gap: 8px; }
.card .cefr { font-size: 11px; font-weight: 800; background: var(--accent); color: #fff; padding: 2px 8px; border-radius: 20px; }
.card p { margin: 8px 0 0; font-size: 13.5px; color: var(--text-soft); }
.card .card-meta { margin-top: 12px; font-size: 12px; color: var(--text-soft); font-weight: 600; }

/* ---------------- Nivel: cabecera ---------------- */

.level-header { margin-bottom: 28px; }
.level-header .kicker {
  display: inline-block; font-size: 11px; font-weight: 800; letter-spacing: .1em;
  text-transform: uppercase; color: var(--accent-text); background: var(--accent-soft);
  padding: 4px 10px; border-radius: 20px; margin-bottom: 12px;
}
.level-header h1 { margin: 0 0 8px; font-size: clamp(24px, 3.6vw, 34px); letter-spacing: -.02em; }
.level-header .lead { color: var(--text-soft); font-size: 16px; margin: 0; max-width: 720px; }

.cando {
  background: var(--bg-elev); border: 1px solid var(--border);
  border-left: 4px solid var(--accent);
  border-radius: 12px; padding: 16px 20px; margin: 20px 0 34px;
}
.cando h4 { margin: 0 0 8px; font-size: 13px; text-transform: uppercase; letter-spacing: .06em; color: var(--text-soft); }
.cando ul { margin: 0; padding-left: 20px; }
.cando li { font-size: 14.5px; margin-bottom: 4px; }

/* ---------------- Tema ---------------- */

.topic {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 26px 28px;
  margin-bottom: 22px;
  scroll-margin-top: calc(var(--topbar-h) + 20px);
}
.topic-head { display: flex; align-items: flex-start; gap: 14px; margin-bottom: 6px; }
.topic-num {
  flex-shrink: 0;
  font-size: 12px; font-weight: 800; color: var(--accent-text);
  background: var(--accent-soft); border-radius: 8px;
  padding: 4px 9px; margin-top: 4px;
}
.topic h2 { margin: 0; font-size: 22px; letter-spacing: -.01em; line-height: 1.25; flex: 1; }
.topic h2 .en { display: block; font-size: 13px; font-weight: 600; color: var(--text-soft); letter-spacing: 0; margin-top: 2px; }

.done-toggle {
  flex-shrink: 0; margin-top: 4px;
  display: flex; align-items: center; gap: 6px;
  font-size: 12px; font-weight: 600; color: var(--text-soft);
  background: var(--bg-soft); border: 1px solid var(--border);
  border-radius: 20px; padding: 4px 11px; cursor: pointer;
  user-select: none; font-family: inherit;
}
.done-toggle:hover { border-color: var(--green); color: var(--green); }
.done-toggle.done { background: var(--green-soft); color: var(--green); border-color: transparent; }

.topic .summary { color: var(--text-soft); font-size: 15px; margin: 10px 0 18px; }

.topic h3 {
  font-size: 14px; text-transform: uppercase; letter-spacing: .07em;
  color: var(--text-soft); margin: 26px 0 10px; font-weight: 800;
}
.topic p { margin: 0 0 12px; font-size: 15px; }
.topic ul, .topic ol { margin: 0 0 14px; padding-left: 22px; font-size: 15px; }
.topic li { margin-bottom: 6px; }

code, .en-txt {
  font-family: var(--mono); font-size: .9em;
  background: var(--bg-soft); border: 1px solid var(--border);
  padding: 1px 5px; border-radius: 5px;
}

.formula {
  font-family: var(--mono); font-size: 14px;
  background: var(--accent-soft); color: var(--accent-text);
  border: 1px dashed color-mix(in srgb, var(--accent) 40%, transparent);
  border-radius: 10px; padding: 12px 16px; margin: 0 0 16px;
  overflow-x: auto; white-space: nowrap;
  font-weight: 600;
}

/* Tablas */
.table-wrap { overflow-x: auto; margin: 0 0 18px; border: 1px solid var(--border); border-radius: 12px; }
table { border-collapse: collapse; width: 100%; font-size: 14px; min-width: 420px; }
th, td { padding: 9px 13px; text-align: left; border-bottom: 1px solid var(--border); vertical-align: top; }
th { background: var(--bg-soft); font-weight: 700; font-size: 12.5px; text-transform: uppercase; letter-spacing: .04em; color: var(--text-soft); }
tbody tr:last-child td { border-bottom: none; }
tbody tr:hover { background: var(--bg-soft); }

/* Ejemplos */
.examples { display: flex; flex-direction: column; gap: 8px; margin: 0 0 18px; }
.ex {
  display: flex; flex-direction: column; gap: 2px;
  border-left: 3px solid var(--accent);
  background: var(--bg-soft);
  padding: 9px 14px; border-radius: 0 10px 10px 0;
}
.ex .ex-en { font-weight: 600; font-size: 15px; }
.ex .ex-es { font-size: 13.5px; color: var(--text-soft); font-style: italic; }

/* Errores comunes */
.errors { display: flex; flex-direction: column; gap: 10px; margin: 0 0 18px; }
.err {
  border: 1px solid var(--border); border-radius: 10px;
  padding: 11px 14px; background: var(--bg-soft); font-size: 14.5px;
}
.err .bad { color: var(--red); font-weight: 600; }
.err .bad::before { content: "✗ "; }
.err .good { color: var(--green); font-weight: 600; }
.err .good::before { content: "✓ "; }
.err .note { display: block; font-size: 13px; color: var(--text-soft); margin-top: 3px; }

/* Avisos */
.callout {
  border-radius: 10px; padding: 13px 16px; margin: 0 0 18px;
  font-size: 14.5px; border: 1px solid transparent;
}
.callout strong { display: block; margin-bottom: 3px; font-size: 13px; text-transform: uppercase; letter-spacing: .05em; }
.callout.tip { background: var(--green-soft); border-color: color-mix(in srgb, var(--green) 30%, transparent); color: var(--text); }
.callout.tip strong { color: var(--green); }
.callout.warn { background: var(--amber-soft); border-color: color-mix(in srgb, var(--amber) 35%, transparent); color: var(--text); }
.callout.warn strong { color: var(--amber); }

/* Vocabulario */
.vocab-group { margin-bottom: 26px; }
.vocab-group h3 { font-size: 16px; margin: 0 0 10px; text-transform: none; letter-spacing: 0; color: var(--text); }
.vocab-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(230px, 1fr)); gap: 8px; }
.word {
  background: var(--bg-elev); border: 1px solid var(--border);
  border-radius: 10px; padding: 8px 12px; font-size: 14px;
}
.word b { display: block; font-weight: 700; }
.word .ipa { font-family: var(--mono); font-size: 11.5px; color: var(--accent); }
.word .es { font-size: 13px; color: var(--text-soft); }

/* Paginación entre niveles */
.pager { display: flex; justify-content: space-between; gap: 14px; margin-top: 40px; }
.pager a {
  flex: 1; background: var(--bg-elev); border: 1px solid var(--border);
  border-radius: 12px; padding: 14px 18px; color: var(--text);
}
.pager a:hover { border-color: var(--accent); text-decoration: none; }
.pager a small { display: block; font-size: 11px; color: var(--text-soft); text-transform: uppercase; letter-spacing: .07em; }
.pager a b { font-size: 15px; }
.pager .next { text-align: right; }

.section-divider {
  margin: 44px 0 22px; padding-bottom: 8px;
  border-bottom: 2px solid var(--border);
  font-size: 13px; text-transform: uppercase; letter-spacing: .1em;
  color: var(--text-soft); font-weight: 800;
}

/* ---------------- Responsive ---------------- */

@media (max-width: 960px) {
  .menu-toggle { display: grid; }
  .brand-text { display: none; }
  .sidebar {
    position: fixed; top: var(--topbar-h); left: 0; bottom: 0;
    z-index: 60; transform: translateX(-100%);
    transition: transform .22s ease; height: auto;
    box-shadow: var(--shadow); width: 290px;
  }
  .sidebar.open { transform: translateX(0); }
  .content { padding: 24px 18px 100px; }
  .topic { padding: 20px 18px; }
  .hero { padding: 30px 22px; }
}

@media (max-width: 560px) {
  .topic-head { flex-wrap: wrap; }
  .done-toggle { order: 3; }
  .pager { flex-direction: column; }
  .pager .next { text-align: left; }
}

@media print {
  .topbar, .sidebar, .overlay, .done-toggle, .pager { display: none !important; }
  .content { max-width: 100%; padding: 0; }
  .topic { break-inside: avoid; border: none; padding: 0; margin-bottom: 24px; }
}