/* ============================================================
   MATEMÁTICA 1 — UNCo | Presentación: Ecuaciones
   styles.css
   ============================================================ */

/* ---------- Google Fonts ---------- */
@import url('https://fonts.googleapis.com/css2?family=Roboto:ital,wght@0,300;0,400;0,500;0,700;1,300&family=Roboto+Mono:wght@400;500&family=Roboto+Slab:wght@700;800&display=swap');
/* ---------- Variables ---------- */
:root {
  --bg:          #f4f6f9;
  --surface:     #ffffff;
  --surface-2:   #eef1f5;
  --border:      #d0d7e2;
  --accent:      #1a73e8;
  --accent-glow: rgba(26,115,232,.15);
  --accent-2:    #e8a000;
  --accent-3:    #1e8e3e;
  --accent-4:    #d93025;
  --text:        #1a1a2e;
  --text-muted:  #4a5568;
  --text-dim:    #a0aec0;
  --font-display: 'Roboto Slab', serif;
  --font-body:    'Roboto', sans-serif;
  --font-mono:    'Roboto Mono', monospace;

  --radius:      14px;
  --radius-sm:   8px;
  --slide-w:     98vw;
  --slide-h:     auto;
  --transition:  .4s cubic-bezier(.4,0,.2,1);
}

/* ---------- Reset ---------- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { font-size: 22px; }
body {
  font-family: var(--font-body);
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  overflow-x: hidden;
}

/* ---------- Header ---------- */
#header {
  width: 100%;
  padding: 16px 32px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-bottom: 1px solid var(--border);
  background: var(--surface);
  position: sticky;
  top: 0;
  z-index: 100;
}
#header .brand {
  display: flex;
  flex-direction: column;
  line-height: 1.1;
}
#header .brand .uni {
  font-family: var(--font-display);
  font-size: .7rem;
  font-weight: 600;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: var(--accent-2);
}
#header .brand .materia {
  font-family: var(--font-display);
  font-size: 1.05rem;
  font-weight: 800;
  color: var(--text);
}
#header .slide-counter {
  font-family: var(--font-mono);
  font-size: .85rem;
  color: var(--text-muted);
}
#header .slide-counter span {
  color: var(--accent);
  font-weight: 500;
}

/* ---------- Progress bar ---------- */
#progress-bar {
  width: 100%;
  height: 3px;
  background: var(--border);
  position: sticky;
  top: 57px;
  z-index: 99;
}
#progress-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--accent), var(--accent-2));
  transition: width var(--transition);
  border-radius: 0 2px 2px 0;
}

/* ---------- Stage ---------- */
#stage {
  flex: 1;
  display: flex;
  align-items: stretch;
  justify-content: center;
  padding: 12px 16px;
  perspective: 1200px;
}

/* ---------- Slide ---------- */
.slide {
  width: var(--slide-w);
  min-height: calc(100vh - 120px); /* resta header + footer */
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 52px 60px;
  position: relative;
  overflow: hidden;
  display: none;
  flex-direction: column;
  gap: 24px;
  animation: slideIn var(--transition) both;
}
.slide.active { display: flex; }
.slide.exit   { animation: slideOut var(--transition) both; }

@keyframes slideIn {
  from { opacity:0; transform: translateY(24px) scale(.98); }
  to   { opacity:1; transform: translateY(0)    scale(1);   }
}
@keyframes slideOut {
  from { opacity:1; transform: translateY(0)    scale(1);   }
  to   { opacity:0; transform: translateY(-24px) scale(.98); }
}

/* Accent stripe */
.slide::before {
  content: '';
  position: absolute;
  top: 0; left: 0;
  width: 5px; height: 100%;
  background: linear-gradient(180deg, var(--accent) 0%, var(--accent-2) 100%);
  border-radius: var(--radius) 0 0 var(--radius);
}

/* Corner ornament */
.slide::after {
  content: attr(data-index);
  position: absolute;
  bottom: 20px; right: 28px;
  font-family: var(--font-mono);
  font-size: 5rem;
  font-weight: 800;
  color: #e2e8f0;
  line-height: 1;
  user-select: none;
  pointer-events: none;
}

/* ---------- Slide title ---------- */
.slide-title {
  font-family: var(--font-display);
  font-size: 1.85rem;
  font-weight: 800;
  line-height: 1.15;
  color: var(--text);
  padding-bottom: 14px;
  border-bottom: 1px solid var(--border);
}
.slide-title .tag {
  display: inline-block;
  font-size: .65rem;
  font-weight: 600;
  letter-spacing: .12em;
  text-transform: uppercase;
  background: var(--accent-glow);
  color: var(--accent);
  border: 1px solid rgba(79,156,249,.4);
  border-radius: 4px;
  padding: 2px 8px;
  vertical-align: middle;
  margin-right: 10px;
  position: relative;
  top: -3px;
}

/* ---------- Slide cover (slide 0) ---------- */
.slide.cover {
  justify-content: center;
  align-items: flex-start;
  gap: 0;
  background: radial-gradient(ellipse 80% 60% at 70% 40%, rgba(79,156,249,.12) 0%, transparent 70%),
              var(--surface);
}
.slide.cover::before { background: linear-gradient(180deg, var(--accent-2), var(--accent)); }
.cover-eyebrow {
  font-family: var(--font-display);
  font-size: .75rem;
  font-weight: 600;
  letter-spacing: .2em;
  text-transform: uppercase;
  color: var(--accent-2);
  margin-bottom: 20px;
}
.cover-title {
  font-family: var(--font-display);
  font-size: 3.2rem;
  font-weight: 800;
  line-height: 1.08;
  color: var(--text);
  margin-bottom: 12px;
}
.cover-title span { color: var(--accent); }
.cover-subtitle {
  font-size: 1.05rem;
  font-weight: 300;
  color: var(--text-muted);
  margin-bottom: 36px;
}
.cover-meta {
  display: flex;
  gap: 24px;
  flex-wrap: wrap;
}
.cover-meta .chip {
  display: flex;
  align-items: center;
  gap: 7px;
  font-size: .8rem;
  color: var(--text-muted);
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: 50px;
  padding: 5px 14px;
}
.cover-meta .chip svg { width:14px; height:14px; stroke: var(--accent-2); }

/* ---------- Body text ---------- */
.slide p, .slide li {
  font-size: .97rem;
  font-weight: 300;
  line-height: 1.75;
  color: var(--text-muted);
}
.slide p strong, .slide li strong { color: var(--text); font-weight: 500; }

/* ---------- Definition box ---------- */
.def-box {
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-left: 4px solid var(--accent);
  border-radius: var(--radius-sm);
  padding: 18px 22px;
  display: flex;
  flex-direction: column;
  gap: 8px;
}
.def-box .def-label {
  font-family: var(--font-display);
  font-size: .68rem;
  font-weight: 700;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: var(--accent);
}

/* ---------- Note / Obs box ---------- */
.note-box {
  background: rgba(247,201,72,.07);
  border: 1px solid rgba(247,201,72,.3);
  border-left: 4px solid var(--accent-2);
  border-radius: var(--radius-sm);
  padding: 14px 20px;
}
.note-box .note-label {
  font-family: var(--font-display);
  font-size: .68rem;
  font-weight: 700;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: var(--accent-2);
  margin-bottom: 5px;
}

/* ---------- Equation display ---------- */
.eq-display {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 18px 24px;
  text-align: center;
  font-size: 1.1rem;
  overflow-x: auto;
}

/* ---------- Members diagram ---------- */
.members-diagram {
  display: flex;
  align-items: center;
  gap: 0;
  justify-content: center;
  flex-wrap: wrap;
}
.member-box {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 6px;
}
.member-box .label {
  font-size: .72rem;
  font-weight: 600;
  letter-spacing: .1em;
  text-transform: uppercase;
  color: var(--accent);
}
.member-box .content {
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 10px 20px;
  font-size: 1rem;
  text-align: center;
}
.eq-sign {
  font-family: var(--font-mono);
  font-size: 1.8rem;
  color: var(--accent-2);
  padding: 0 16px;
  margin-top: 18px;
}

/* ---------- Property cards ---------- */
.prop-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 14px;
}
.prop-card {
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 16px 18px;
  display: flex;
  flex-direction: column;
  gap: 8px;
}
.prop-card .prop-num {
  font-family: var(--font-display);
  font-size: .68rem;
  font-weight: 800;
  letter-spacing: .12em;
  text-transform: uppercase;
  color: var(--accent-3);
}
.prop-card p { font-size: .9rem; }

/* ---------- Steps list ---------- */
.steps {
  display: flex;
  flex-direction: column;
  gap: 10px;
  list-style: none;
  counter-reset: step;
}
.steps li {
  display: flex;
  gap: 14px;
  align-items: flex-start;
  counter-increment: step;
  font-size: .92rem;
}
.steps li::before {
  content: counter(step);
  min-width: 26px;
  height: 26px;
  border-radius: 50%;
  background: var(--accent);
  color: #fff;
  font-family: var(--font-display);
  font-size: .75rem;
  font-weight: 800;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-top: 2px;
  flex-shrink: 0;
}

/* ---------- Example / Resolution ---------- */
.resolution {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 18px 22px;
  display: flex;
  flex-direction: column;
  gap: 10px;
}
.resolution .res-title {
  font-family: var(--font-display);
  font-size: .7rem;
  font-weight: 700;
  letter-spacing: .13em;
  text-transform: uppercase;
  color: var(--accent-3);
  border-bottom: 1px solid var(--border);
  padding-bottom: 8px;
}
.res-line {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: .93rem;
}
.res-ann {
  font-size: .75rem;
  color: var(--text-dim);
  font-style: italic;
}

/* ---------- Solution pill ---------- */
.solution-pill {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: rgba(92,230,155,.1);
  border: 1px solid rgba(92,230,155,.35);
  border-radius: 50px;
  padding: 7px 18px;
  font-size: .88rem;
  color: var(--accent-3);
}
.solution-pill svg { width:14px; height:14px; }

/* ---------- Special cases ---------- */
.case-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 14px;
}
.case-card {
  border-radius: var(--radius-sm);
  padding: 16px 18px;
  display: flex;
  flex-direction: column;
  gap: 8px;
}
.case-card.valid {
  background: rgba(92,230,155,.08);
  border: 1px solid rgba(92,230,155,.3);
}
.case-card.invalid {
  background: rgba(249,111,79,.08);
  border: 1px solid rgba(249,111,79,.3);
}
.case-card .case-label {
  font-family: var(--font-display);
  font-size: .68rem;
  font-weight: 800;
  letter-spacing: .12em;
  text-transform: uppercase;
}
.case-card.valid   .case-label { color: var(--accent-3); }
.case-card.invalid .case-label { color: var(--accent-4); }

/* ---------- Two-column layout ---------- */
.two-col {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
}

/* ---------- Controls ---------- */
#controls {
  width: 100%;
  padding: 18px 32px;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 16px;
  border-top: 1px solid var(--border);
  background: var(--surface);
}
.ctrl-btn {
  display: flex;
  align-items: center;
  gap: 8px;
  background: var(--surface-2);
  border: 1px solid var(--border);
  color: var(--text);
  font-family: var(--font-body);
  font-size: .85rem;
  font-weight: 500;
  padding: 9px 20px;
  border-radius: 50px;
  cursor: pointer;
  transition: background var(--transition), border-color var(--transition), transform .15s;
}
.ctrl-btn:hover:not(:disabled) {
  background: var(--border);
  border-color: var(--accent);
  transform: translateY(-1px);
}
.ctrl-btn:disabled { opacity: .35; cursor: default; }
.ctrl-btn.primary {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
}
.ctrl-btn.primary:hover:not(:disabled) {
  background: #3a8de0;
  border-color: #3a8de0;
}

/* ---------- Dot navigation ---------- */
#dots {
  display: flex;
  gap: 8px;
  align-items: center;
}
.dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--border);
  border: none;
  cursor: pointer;
  transition: background var(--transition), width var(--transition), border-radius var(--transition);
  padding: 0;
}
.dot.active {
  width: 24px;
  border-radius: 4px;
  background: var(--accent);
}
.dot:hover:not(.active) { background: var(--text-muted); }

/* ---------- MathJax overrides ---------- */
mjx-container {
  overflow-x: auto;
  color: var(--text) !important;
}

/* ---------- Responsive ---------- */
@media (max-width: 960px) {
  :root { --slide-w: 96vw; --slide-h: auto; }
  .slide { padding: 36px 32px; }
  .prop-grid, .two-col, .case-grid { grid-template-columns: 1fr; }
  .cover-title { font-size: 2.2rem; }
}
@media (max-width: 600px) {
  .slide { padding: 28px 20px; }
  .slide-title { font-size: 1.4rem; }
  #controls { flex-wrap: wrap; gap: 10px; }
}