/* NEXTUMAX LEARNING TOPICS */

.topic-main {
  width: min(var(--max), calc(100% - var(--page-gutter)));
  margin: 0 auto;
  padding: 30px 0 54px;
}

.topic-hero {
  max-width: 860px;
  padding-bottom: 24px;
  border-bottom: 1px solid var(--border);
}

.topic-hero h1 {
  max-width: 760px;
  margin: 10px 0 8px;
  font-size: clamp(2rem, 4vw, 3.15rem);
  line-height: 1.08;
  letter-spacing: 0;
}

.topic-hero > p:not(.career-kicker) {
  max-width: 760px;
  margin-bottom: 0;
  color: var(--muted);
  font-size: 0.98rem;
  line-height: 1.65;
}

.topic-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 18px;
  margin-top: 14px;
  color: var(--muted);
  font-size: 0.8rem;
  font-weight: 750;
}

.topic-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 260px;
  gap: clamp(28px, 5vw, 68px);
  align-items: start;
  padding-top: 12px;
}

.topic-content {
  min-width: 0;
}

.topic-section {
  padding: 28px 0;
  border-bottom: 1px solid var(--border);
}

.topic-section h2 {
  margin-bottom: 10px;
  font-size: clamp(1.3rem, 2.3vw, 1.7rem);
  line-height: 1.2;
  letter-spacing: 0;
}

.topic-section h3 {
  margin: 20px 0 8px;
  font-size: 1rem;
}

.topic-section p,
.topic-section li {
  color: var(--muted);
  line-height: 1.7;
}

.topic-section ul,
.topic-section ol {
  margin: 12px 0 0;
  padding-left: 20px;
}

.topic-section li + li {
  margin-top: 8px;
}

.formula-strip {
  margin: 16px 0;
  padding: 14px 16px;
  border-left: 3px solid var(--accent);
  background: rgba(46, 229, 139, 0.055);
  color: var(--text);
  font-family: "Cascadia Code", Consolas, monospace;
  font-size: 0.9rem;
  line-height: 1.75;
  overflow-wrap: anywhere;
}

.worked-example {
  margin-top: 16px;
  padding: 16px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--card);
}

.worked-example strong {
  display: block;
  margin-bottom: 6px;
  color: var(--accent);
}

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

.lesson-visual {
  margin: 18px 0;
  padding: 18px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--card-strong);
  overflow-x: auto;
}

.visual-caption {
  margin: 12px 0 0;
  color: var(--muted);
  font-size: 0.78rem;
  line-height: 1.45;
}

.signal-line,
.state-flow,
.uvm-flow,
.bit-row,
.fifo-flow {
  display: flex;
  align-items: center;
  gap: 8px;
  min-width: max-content;
}

.signal-line span,
.state-flow span,
.uvm-flow span,
.fifo-flow span {
  padding: 8px 10px;
  border: 1px solid var(--border);
  border-radius: 6px;
  color: var(--text);
  font-size: 0.78rem;
  font-weight: 800;
}

.signal-line b,
.state-flow b,
.uvm-flow b,
.fifo-flow b {
  color: var(--accent);
  font-size: 0.9rem;
}

.bit-row {
  gap: 4px;
}

.bit-row span {
  width: 34px;
  height: 34px;
  display: grid;
  place-items: center;
  border: 1px solid var(--border);
  border-radius: 5px;
  color: var(--text);
  font-family: "Cascadia Code", Consolas, monospace;
  font-weight: 800;
}

.bit-row span:first-child {
  border-color: rgba(46, 229, 139, 0.5);
  color: var(--accent);
}

.kmap-demo {
  display: grid;
  grid-template-columns: repeat(4, 42px);
  gap: 5px;
  width: max-content;
}

.kmap-demo span {
  min-height: 38px;
  display: grid;
  place-items: center;
  border: 1px solid var(--border);
  border-radius: 5px;
  color: var(--text);
  font-family: "Cascadia Code", Consolas, monospace;
}

.kmap-demo .group-a { background: rgba(46, 229, 139, 0.14); }
.kmap-demo .group-b { box-shadow: inset 0 0 0 2px rgba(248, 201, 107, 0.55); }

.topic-aside {
  position: sticky;
  top: 98px;
  display: grid;
  gap: 0;
  margin-top: 16px;
  border-top: 1px solid var(--border);
}

.topic-aside > span {
  padding: 14px 0 8px;
  color: var(--accent);
  font-size: 0.76rem;
  font-weight: 900;
  text-transform: uppercase;
}

.topic-aside a {
  padding: 10px 0;
  border-bottom: 1px solid var(--border);
  color: var(--muted);
  font-size: 0.86rem;
  font-weight: 750;
  text-decoration: none;
}

.topic-aside a:hover {
  color: var(--accent);
}

.topic-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  padding-top: 24px;
}

.topic-actions .primary-btn,
.topic-actions .outline-btn {
  min-height: 42px;
  padding-inline: 16px;
  font-size: 0.86rem;
}

.topic-hub-list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 8px;
  margin-top: 22px;
}

.topic-hub-link {
  display: grid;
  grid-template-columns: 42px minmax(0, 1fr);
  gap: 10px;
  align-items: center;
  min-height: 68px;
  padding: 10px 12px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--card);
  color: inherit;
  text-decoration: none;
}

.topic-hub-link:hover {
  border-color: rgba(46, 229, 139, 0.4);
  background: var(--surface-hover);
}

.topic-hub-link > span:first-child {
  color: var(--accent);
  font-size: 0.72rem;
  font-weight: 950;
}

.topic-hub-link strong,
.topic-hub-link small {
  display: block;
}

.topic-hub-link strong {
  margin-bottom: 3px;
  font-size: 0.9rem;
}

.topic-hub-link small {
  color: var(--muted);
  font-size: 0.78rem;
  line-height: 1.4;
}

.tool-learning-links {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px 14px;
  margin-top: 14px;
  padding-top: 14px;
  border-top: 1px solid var(--border);
}

.tool-learning-links span {
  color: var(--muted);
  font-size: 0.8rem;
  font-weight: 800;
}

.tool-learning-links a {
  color: var(--accent);
  font-size: 0.82rem;
  font-weight: 850;
  text-decoration: none;
}

@media (max-width: 820px) {
  .topic-layout {
    grid-template-columns: 1fr;
  }

  .topic-aside {
    position: static;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    column-gap: 18px;
    order: -1;
  }

  .topic-aside > span {
    grid-column: 1 / -1;
  }
}

@media (max-width: 640px) {
  .topic-main {
    width: min(var(--max), calc(100% - 56px));
    padding-top: 22px;
  }

  .topic-hero h1 {
    font-size: clamp(1.5rem, 7vw, 1.8rem);
    line-height: 1.16;
  }

  .topic-hero > p:not(.career-kicker),
  .topic-section p,
  .topic-section li {
    font-size: 0.86rem;
  }

  .topic-hub-list,
  .topic-aside {
    grid-template-columns: 1fr;
  }

  .topic-section {
    padding: 22px 0;
  }

  .lesson-visual,
  .worked-example {
    padding: 13px;
  }

  .topic-actions {
    display: grid;
  }
}