/* =========================================
   Magister Studio — Nombres Complexes
   Minimal, encyclopedic, black & white
   ========================================= */

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

:root {
  --bg: #000;
  --text: #e8e8e8;
  --text-muted: #777;
  --border: #1a1a1a;
  --card-bg: #0a0a0a;
  --card-hover: #111;
  --font: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
}

html {
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  line-height: 1.75;
  min-height: 100vh;
}

a { color: var(--text); }

::selection {
  background: #333;
  color: #fff;
}

/* ========== NAV ========== */
.nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1.5rem 2.5rem;
  position: sticky;
  top: 0;
  background: rgba(0,0,0,0.92);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  z-index: 100;
  border-bottom: 1px solid var(--border);
}

.nav-back {
  font-size: 0.82rem;
  color: var(--text-muted);
  text-decoration: none;
  transition: color 0.2s;
}
.nav-back:hover { color: var(--text); }

.nav-title {
  position: absolute;
  left: 50%;
  transform: translateX(-50%) translateY(-4px);
  font-size: 0.82rem;
  font-weight: 500;
  color: #fff;
  opacity: 0;
  transition: opacity 0.3s, transform 0.3s;
  pointer-events: none;
}

.nav-title.visible {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}

.nav-contact {
  font-size: 0.82rem;
  color: var(--text-muted);
  text-decoration: none;
  transition: color 0.2s;
}
.nav-contact:hover { color: var(--text); }

/* ========== MAIN ========== */
main {
  max-width: 640px;
  margin: 0 auto;
  padding: 0 2rem;
}

/* ========== HEADER ========== */
.page-header {
  padding: 4rem 0 2rem;
}

.page-header h1 {
  font-size: 2rem;
  font-weight: 600;
  letter-spacing: -0.5px;
  line-height: 1.2;
  color: #fff;
}

.subtitle {
  margin-top: 0.5rem;
  font-size: 0.82rem;
  color: var(--text-muted);
  font-weight: 400;
}

/* ========== DIVIDER ========== */
.divider {
  height: 1px;
  background: var(--border);
}

/* ========== SECTION ========== */
.section {
  padding: 2.5rem 0;
}

.section h2 {
  font-size: 1.1rem;
  font-weight: 600;
  letter-spacing: -0.2px;
  margin-bottom: 1.5rem;
  color: #fff;
}

.section p {
  font-size: 0.95rem;
  font-weight: 300;
  color: var(--text);
  margin-bottom: 1.2rem;
  line-height: 1.8;
}

.section p:last-child { margin-bottom: 0; }

.section p strong {
  font-weight: 500;
  color: #fff;
}

.section p em {
  font-style: italic;
}

/* ========== CHAPTERS ========== */
.chapter-list {
  list-style: none;
  counter-reset: chapter;
}

.chapter-list li {
  position: relative;
  padding: 0.6rem 0 0.6rem 1.6rem;
  font-size: 0.95rem;
  font-weight: 300;
  color: var(--text);
  border-bottom: 1px solid var(--border);
  counter-increment: chapter;
}

.chapter-list li:first-child {
  border-top: 1px solid var(--border);
}

.chapter-list li::before {
  content: counter(chapter, decimal-leading-zero);
  position: absolute;
  left: 0;
  color: var(--text-muted);
  font-size: 0.75rem;
  font-weight: 400;
  top: 50%;
  transform: translateY(-50%);
}

/* ========== VIDEO ========== */
.video-wrap {
  margin-bottom: 1.2rem;
}

.video-container {
  position: relative;
  width: 100%;
  padding-top: 56.25%;
  border-radius: 6px;
  overflow: hidden;
  border: 1px solid var(--border);
  background: var(--card-bg);
}

.video-container iframe {
  position: absolute;
  top: 0; left: 0;
  width: 100%; height: 100%;
  border: none;
}

.playlist-link {
  display: inline-block;
  font-size: 0.85rem;
  font-weight: 400;
  color: var(--text-muted);
  text-decoration: none;
  transition: color 0.2s;
}
.playlist-link:hover { color: #fff; }

/* ========== CARDS ========== */
.cards {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.8rem;
}

.card {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  padding: 1.3rem 1.4rem;
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: 6px;
  text-decoration: none;
  transition: background 0.2s, border-color 0.2s;
}

.card:hover {
  background: var(--card-hover);
  border-color: #2a2a2a;
}

.card-top {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 0.5rem;
}

.card-title {
  font-size: 0.9rem;
  font-weight: 500;
  color: #fff;
}

.card-price {
  font-size: 0.82rem;
  font-weight: 400;
  color: var(--text-muted);
  white-space: nowrap;
}

.card-price.free {
  color: #888;
}

.card-desc {
  font-size: 0.78rem;
  font-weight: 300;
  color: var(--text-muted);
  line-height: 1.55;
  margin: 0 !important;
}

/* ========== MODAL POPUP ========== */
.modal-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.8);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 9999;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.3s ease;
  padding: 1rem;
}

.modal-overlay.active {
  opacity: 1;
  pointer-events: auto;
}

.modal-box {
  background: #111;
  border: 1px solid #222;
  border-radius: 12px;
  padding: 2rem;
  max-width: 420px;
  width: 100%;
  position: relative;
  box-shadow: 0 20px 50px rgba(0, 0, 0, 0.7);
  transform: translateY(20px);
  transition: transform 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

.modal-overlay.active .modal-box {
  transform: translateY(0);
}

.modal-close {
  position: absolute;
  top: 1.2rem;
  right: 1.2rem;
  background: transparent;
  border: none;
  color: #666;
  font-size: 1.5rem;
  cursor: pointer;
  line-height: 1;
  transition: color 0.2s;
}

.modal-close:hover {
  color: #fff;
}

.modal-box h3 {
  font-size: 1.1rem;
  font-weight: 500;
  color: #fff;
  margin: 0 0 0.5rem 0;
}

.modal-box p {
  font-size: 0.82rem;
  color: var(--text-muted);
  line-height: 1.5;
  margin: 0 0 1.5rem 0;
}

.free-form {
  display: flex;
  flex-direction: column;
  gap: 0.8rem;
}

.free-form input {
  padding: 0.75rem 1rem;
  background: #080808;
  border: 1px solid #282828;
  border-radius: 6px;
  color: var(--text);
  font-family: var(--font);
  font-size: 0.85rem;
  outline: none;
  transition: border-color 0.2s;
}

.free-form input:focus {
  border-color: #555;
}

.free-form input::placeholder {
  color: #555;
}

.free-form button {
  padding: 0.75rem 1rem;
  background: #fff;
  color: #000;
  border: none;
  border-radius: 6px;
  font-family: var(--font);
  font-size: 0.85rem;
  font-weight: 600;
  cursor: pointer;
  transition: opacity 0.2s;
}

.free-form button:hover { opacity: 0.85; }
.free-form button:disabled { opacity: 0.4; cursor: wait; }

.form-msg {
  font-size: 0.78rem;
  margin-top: 0.8rem;
  min-height: 1rem;
  text-align: center;
}

.form-success { color: #888; }
.form-error { color: #c44; }


/* ========== FOOTER ========== */
.footer {
  margin-top: 2rem;
  padding: 2rem 2.5rem;
  border-top: 1px solid var(--border);
  text-align: center;
  font-size: 0.75rem;
  color: var(--text-muted);
  font-weight: 300;
}

/* ========== RESPONSIVE ========== */
@media (max-width: 600px) {
  .nav { padding: 1rem 1.2rem; }
  .nav-contact { display: none; }

  main { padding: 0 1.2rem; }

  .page-header { padding: 2.5rem 0 1.5rem; }
  .page-header h1 { font-size: 1.6rem; }

  .section { padding: 2rem 0; }

  .cards { grid-template-columns: 1fr; }
}