/* ============================================================
   Guía de Estudio — Dirección de Operaciones
   Paleta "expediente de operaciones": papel técnico + tinta
   marina + acento óxido (industria) + acento verde (investigación)
   ============================================================ */

:root {
  --paper: #efeee7;
  --paper-raised: #f9f8f3;
  --ink: #16233b;
  --ink-soft: #4b5872;
  --ink-faint: #7c869a;
  --line: #d8d3c3;
  --line-strong: #b9b3a0;

  --accent: #b6542a;
  --accent-ink: #7c3a1c;
  --accent-soft: #f1decb;

  --research: #2f6e63;
  --research-soft: #dfece7;

  --correct: #2e7d4f;
  --correct-soft: #dcefe2;
  --incorrect: #b23a3a;
  --incorrect-soft: #f7e1de;

  --font-display: "Space Grotesk", "Helvetica Neue", Arial, sans-serif;
  --font-body: "Source Serif 4", Georgia, "Times New Roman", serif;

  --radius-sm: 3px;
  --radius-md: 6px;
  --content-max: 44rem;

  --shadow-tab: 0 1px 0 var(--line-strong);
}

* {
  box-sizing: border-box;
}

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
  * {
    animation-duration: 0.001ms !important;
    transition-duration: 0.001ms !important;
  }
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
}

img,
svg {
  max-width: 100%;
  display: block;
}

a {
  color: var(--accent-ink);
}

::selection {
  background: var(--accent-soft);
}

/* ---------- Skip link ---------- */
.skip-link {
  position: absolute;
  left: -999px;
  top: auto;
  background: var(--ink);
  color: var(--paper-raised);
  padding: 0.75rem 1rem;
  z-index: 100;
  border-radius: var(--radius-sm);
}
.skip-link:focus {
  left: 1rem;
  top: 1rem;
}

/* ---------- Header ---------- */
.site-header {
  padding: 1.75rem 1.1rem 1.25rem;
  border-bottom: 1px solid var(--line);
  background: linear-gradient(180deg, var(--paper-raised), var(--paper));
}

.header-inner {
  max-width: var(--content-max);
  margin: 0 auto;
}

.course-tag {
  font-family: var(--font-display);
  font-size: 0.72rem;
  letter-spacing: 0.03em;
  color: var(--ink-faint);
  margin: 0 0 0.35rem;
}

.site-title {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.65rem;
  line-height: 1.15;
  margin: 0 0 0.5rem;
  color: var(--ink);
  letter-spacing: -0.01em;
}

.site-title em {
  font-style: normal;
  color: var(--accent-ink);
}

.site-subtitle {
  font-family: var(--font-body);
  font-style: italic;
  font-size: 1.02rem;
  color: var(--ink-soft);
  margin: 0;
  max-width: 34rem;
}

/* ---------- Tab navigation ---------- */
.tab-nav {
  position: sticky;
  top: 0;
  z-index: 20;
  background: var(--paper-raised);
  border-bottom: 1px solid var(--line-strong);
  box-shadow: var(--shadow-tab);
}

.tab-nav-inner {
  max-width: var(--content-max);
  margin: 0 auto;
  display: flex;
  overflow-x: auto;
  scrollbar-width: thin;
  -webkit-overflow-scrolling: touch;
}

.tab-btn {
  flex: 0 0 auto;
  font-family: var(--font-display);
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--ink-soft);
  background: transparent;
  border: none;
  border-bottom: 3px solid transparent;
  padding: 0.85rem 0.95rem;
  cursor: pointer;
  white-space: nowrap;
  transition: color 0.15s ease, border-color 0.15s ease;
}

.tab-btn .tab-num {
  color: var(--ink-faint);
  margin-right: 0.35rem;
  font-weight: 500;
}

.tab-btn:hover {
  color: var(--ink);
}

.tab-btn[aria-selected="true"] {
  color: var(--accent-ink);
  border-bottom-color: var(--accent);
}

.tab-btn[aria-selected="true"] .tab-num {
  color: var(--accent);
}

.tab-btn:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: -2px;
}

/* ---------- Main layout ---------- */
main {
  max-width: var(--content-max);
  margin: 0 auto;
  padding: 1.25rem 1.1rem 4rem;
}

.panel {
  display: none;
}
.panel.is-active {
  display: block;
  animation: fade-in 0.25s ease;
}

@keyframes fade-in {
  from { opacity: 0; transform: translateY(4px); }
  to { opacity: 1; transform: translateY(0); }
}

/* ---------- Case dossier header ---------- */
.case-header {
  margin: 0.25rem 0 1.75rem;
}

.case-eyebrow {
  font-family: var(--font-display);
  font-size: 0.72rem;
  color: var(--ink-faint);
  margin: 0 0 0.4rem;
}

.case-title {
  font-family: var(--font-display);
  font-size: 1.55rem;
  font-weight: 700;
  color: var(--ink);
  margin: 0 0 0.3rem;
  letter-spacing: -0.01em;
}

.case-author {
  font-size: 0.92rem;
  color: var(--ink-faint);
  margin: 0 0 0.85rem;
  font-style: italic;
}

.module-chips {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  margin: 0;
  padding: 0;
  list-style: none;
}

.module-chips li {
  font-family: var(--font-display);
  font-size: 0.72rem;
  font-weight: 600;
  border: 1px solid var(--line-strong);
  color: var(--ink-soft);
  padding: 0.25rem 0.55rem;
  border-radius: 999px;
  background: var(--paper-raised);
}

/* ---------- Section blocks (resumen / caso / investigación) ---------- */
.block {
  margin-bottom: 2rem;
  border-radius: var(--radius-md);
  overflow: hidden;
  border: 1px solid var(--line);
}

.block-head {
  display: flex;
  align-items: baseline;
  gap: 0.55rem;
  padding: 0.9rem 1.1rem;
  font-family: var(--font-display);
}

.block-index {
  font-weight: 700;
  font-size: 0.85rem;
  color: var(--ink-faint);
}

.block-head h2 {
  margin: 0;
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--ink);
}

.block-body {
  padding: 0.15rem 1.1rem 1.2rem;
  background: var(--paper-raised);
}

.block--resumen .block-head {
  background: var(--accent-soft);
}
.block--resumen .block-head h2 {
  color: var(--accent-ink);
}

.block--caso .block-head {
  background: var(--paper);
  border-bottom: 1px solid var(--line);
}

.block--investigacion .block-head {
  background: var(--research-soft);
}
.block--investigacion .block-head h2 {
  color: var(--research);
}

.block-body p {
  margin: 0 0 1rem;
  max-width: 38rem;
}
.block-body p:last-child {
  margin-bottom: 0;
}

.block--resumen .block-body {
  font-family: var(--font-body);
  font-size: 1.02rem;
  color: var(--ink);
}

.block--caso .block-body h3 {
  font-family: var(--font-display);
  font-size: 0.98rem;
  font-weight: 700;
  color: var(--accent-ink);
  margin: 1.6rem 0 0.6rem;
  padding-top: 0.2rem;
  border-top: 1px solid var(--line);
}
.block--caso .block-body h3:first-child {
  margin-top: 0.6rem;
  border-top: none;
  padding-top: 0;
}

.block--caso .block-body p {
  font-size: 1.02rem;
  line-height: 1.68;
}

.block--investigacion .block-body h3 {
  font-family: var(--font-display);
  font-size: 0.92rem;
  font-weight: 700;
  color: var(--research);
  margin: 1.3rem 0 0.5rem;
}
.block--investigacion .block-body h3:first-child {
  margin-top: 0.4rem;
}

.block--investigacion .block-body p {
  font-size: 0.98rem;
}

.source-note {
  margin-top: 1rem;
  padding: 0.75rem 0.9rem;
  background: var(--paper);
  border: 1px dashed var(--line-strong);
  border-radius: var(--radius-sm);
  font-family: var(--font-display);
  font-size: 0.78rem;
  color: var(--ink-faint);
  line-height: 1.5;
}

/* ---------- Exam panel ---------- */
.exam-intro {
  margin-bottom: 1.5rem;
}

.exam-intro h2 {
  font-family: var(--font-display);
  font-size: 1.4rem;
  margin: 0.2rem 0 0.5rem;
}

.exam-intro p {
  color: var(--ink-soft);
  max-width: 36rem;
}

.exam-group {
  margin-bottom: 2.1rem;
}

.exam-group-title {
  font-family: var(--font-display);
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--ink);
  border-bottom: 2px solid var(--ink);
  padding-bottom: 0.4rem;
  margin: 0 0 1rem;
}

.question-card {
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
  background: var(--paper-raised);
  padding: 1rem 1.05rem 1.05rem;
  margin-bottom: 1rem;
}

.question-top {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: center;
  gap: 0.45rem 0.6rem;
  margin-bottom: 0.55rem;
}

.question-num {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 0.9rem;
  color: var(--ink-faint);
  white-space: nowrap;
}

.question-hint {
  font-family: var(--font-display);
  font-size: 0.7rem;
  color: var(--accent-ink);
  background: var(--accent-soft);
  border-radius: 999px;
  padding: 0.15rem 0.55rem;
  white-space: nowrap;
  margin-right: auto;
}

.question-prompt {
  margin: 0 0 0.75rem;
  font-size: 1rem;
  line-height: 1.5;
}

.option-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 0.45rem;
}

.option-item {
  display: flex;
  align-items: flex-start;
  gap: 0.6rem;
  padding: 0.55rem 0.65rem;
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  background: var(--paper);
  cursor: pointer;
  transition: border-color 0.15s ease, background 0.15s ease;
}

.option-item:hover {
  border-color: var(--ink-faint);
}

.option-item input {
  margin-top: 0.2rem;
  accent-color: var(--accent);
  flex: 0 0 auto;
}

.option-item span {
  font-size: 0.96rem;
  line-height: 1.4;
}

.option-item.is-checked {
  border-color: var(--accent);
  background: var(--accent-soft);
}

/* grading states */
.question-card.state-correct {
  border-color: var(--correct);
  background: var(--correct-soft);
}
.question-card.state-incorrect {
  border-color: var(--incorrect);
  background: var(--incorrect-soft);
}

.option-item.opt-correct-answer {
  border-color: var(--correct);
  background: var(--correct-soft);
}
.option-item.opt-wrong-selected {
  border-color: var(--incorrect);
  background: var(--incorrect-soft);
}

.result-tag {
  font-family: var(--font-display);
  font-size: 0.78rem;
  font-weight: 700;
  padding: 0.15rem 0.55rem;
  border-radius: 999px;
  white-space: nowrap;
}
.result-tag.tag-correct {
  color: var(--correct);
  background: #ffffffaa;
}
.result-tag.tag-incorrect {
  color: var(--incorrect);
  background: #ffffffaa;
}

.feedback-box {
  margin-top: 0.7rem;
  padding: 0.65rem 0.75rem;
  border-radius: var(--radius-sm);
  font-size: 0.9rem;
  line-height: 1.5;
  display: none;
}
.question-card.state-incorrect .feedback-box {
  display: block;
  background: #ffffffbb;
  border: 1px solid var(--incorrect);
}
.question-card.state-correct .feedback-box.show-on-correct {
  display: block;
  background: #ffffffbb;
  border: 1px solid var(--correct);
}

.feedback-box strong {
  display: block;
  margin-bottom: 0.2rem;
  font-family: var(--font-display);
  font-size: 0.78rem;
  letter-spacing: 0.01em;
}

/* ---------- Submit / results ---------- */
.exam-submit-row {
  position: sticky;
  bottom: 0.7rem;
  display: flex;
  justify-content: center;
  padding-top: 0.5rem;
}

.btn-submit {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1rem;
  color: var(--paper-raised);
  background: var(--ink);
  border: none;
  padding: 0.85rem 1.9rem;
  border-radius: 999px;
  cursor: pointer;
  box-shadow: 0 4px 14px rgba(22, 35, 59, 0.28);
  transition: transform 0.12s ease, background 0.15s ease;
}

.btn-submit:hover {
  background: var(--accent-ink);
}
.btn-submit:active {
  transform: translateY(1px);
}
.btn-submit:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.results-panel {
  display: none;
  margin: 1.5rem 0 2rem;
  border: 1px solid var(--line-strong);
  border-radius: var(--radius-md);
  background: var(--paper-raised);
  padding: 1.4rem 1.2rem;
  text-align: center;
}
.results-panel.is-visible {
  display: block;
  animation: fade-in 0.3s ease;
}

.results-eyebrow {
  font-family: var(--font-display);
  font-size: 0.78rem;
  color: var(--ink-faint);
  margin: 0 0 0.3rem;
}

.results-score {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 3rem;
  line-height: 1;
  color: var(--ink);
  margin: 0 0 0.25rem;
}
.results-score span {
  font-size: 1.4rem;
  color: var(--ink-faint);
  font-weight: 600;
}

.results-score.score-good { color: var(--correct); }
.results-score.score-mid { color: var(--accent-ink); }
.results-score.score-low { color: var(--incorrect); }

.results-detail {
  color: var(--ink-soft);
  margin: 0 0 0.9rem;
  font-family: var(--font-body);
}

.results-note {
  font-size: 0.85rem;
  color: var(--ink-faint);
}

/* ---------- Footer ---------- */
.site-footer {
  max-width: var(--content-max);
  margin: 0 auto;
  padding: 1.5rem 1.1rem 3rem;
  color: var(--ink-faint);
  font-size: 0.82rem;
  border-top: 1px solid var(--line);
}

/* ============================================================
   Responsive — tablet & desktop
   ============================================================ */
@media (min-width: 640px) {
  body {
    font-size: 17px;
  }
  .site-header {
    padding: 2.5rem 1.5rem 1.5rem;
  }
  .site-title {
    font-size: 2.1rem;
  }
  .site-subtitle {
    font-size: 1.08rem;
  }
  main {
    padding: 2rem 1.5rem 5rem;
  }
  .case-title {
    font-size: 1.9rem;
  }
  .block-head {
    padding: 1.05rem 1.4rem;
  }
  .block-body {
    padding: 0.2rem 1.4rem 1.5rem;
  }
  .question-card {
    padding: 1.25rem 1.5rem 1.4rem;
  }
  .tab-btn {
    padding: 1rem 1.3rem;
    font-size: 0.9rem;
  }
}

@media (min-width: 960px) {
  .site-header,
  .tab-nav-inner,
  main,
  .site-footer {
    max-width: 52rem;
  }
}