.module-nav {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-left: 26px;
  margin-right: auto;
}

.module-nav a {
  color: var(--muted);
  text-decoration: none;
  border: 1px solid transparent;
  border-radius: 999px;
  padding: 8px 13px;
  font-size: 13px;
  font-weight: 800;
  transition: .2s;
}

.module-nav a:hover,
.module-nav a.active {
  color: var(--green);
  border-color: var(--line);
  background: rgba(255, 255, 255, .55);
}

.portal-main {
  max-width: 1180px;
  margin: 0 auto;
  padding: 70px 0 90px;
}

.portal-hero {
  margin-bottom: 30px;
}

.portal-hero h1 {
  font: 600 clamp(42px, 5vw, 68px)/1.02 Georgia, "Songti SC", serif;
  letter-spacing: -2px;
  margin: 16px 0;
}

.portal-hero p {
  max-width: 720px;
  color: var(--muted);
  font-size: 15px;
  line-height: 1.8;
  margin: 0;
}

.portal-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 26px;
  align-items: stretch;
}

.portal-card {
  overflow: hidden;
  display: flex;
  flex-direction: column;
  min-height: 520px;
}

.portal-visual {
  height: 204px;
  border-bottom: 1px solid var(--line);
  background: linear-gradient(135deg, #eef1e9, #faf9f4);
  position: relative;
  overflow: hidden;
}

.portal-card-body {
  padding: 24px 24px 22px;
  display: flex;
  flex: 1;
  flex-direction: column;
}

.portal-card h2 {
  margin: 0 0 13px;
  font-size: 24px;
  line-height: 1.35;
  letter-spacing: -.5px;
}

.portal-card p {
  color: var(--muted);
  line-height: 1.75;
  margin: 0 0 22px;
}

.portal-card .primary-btn {
  width: fit-content;
  min-height: 44px;
  margin-top: auto;
}

.soon-badge {
  display: inline-flex;
  width: fit-content;
  align-items: center;
  gap: 6px;
  color: var(--green);
  background: #eef3df;
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 5px 10px;
  font-size: 11px;
  font-weight: 800;
  margin-bottom: 12px;
}

.heap-visual {
  background:
    radial-gradient(circle at 18px 18px, rgba(30, 89, 61, .09) 2px, transparent 2px) 0 0/20px 20px,
    linear-gradient(135deg, #eef0ff, #fffdf8);
}

.heap-node {
  position: absolute;
  width: 42px;
  height: 42px;
  border-radius: 50%;
  display: grid;
  place-items: center;
  background: #b9b4ff;
  border: 1px solid #6f66c7;
  color: #18212b;
  font: 700 12px ui-monospace, monospace;
  box-shadow: 0 4px 10px rgba(23, 34, 28, .12);
}

.heap-node.hot {
  background: #ef6c65;
  border-color: #b83d32;
  color: white;
}

.heap-line {
  position: absolute;
  height: 2px;
  background: #4a4c59;
  transform-origin: left center;
  opacity: .75;
}

.hanoi-visual {
  background: #f0f2f4;
}

.peg {
  position: absolute;
  bottom: 36px;
  width: 4px;
  height: 140px;
  background: #9ba4a8;
  border-radius: 4px;
}

.peg:after {
  content: "";
  position: absolute;
  left: -44px;
  bottom: -4px;
  width: 92px;
  height: 7px;
  border-radius: 8px;
  background: #99a3a7;
}

.disk {
  position: absolute;
  left: 50%;
  transform: translateX(-50%);
  height: 13px;
  border-radius: 999px;
  box-shadow: 0 2px 4px rgba(0, 0, 0, .12);
}

.hash-visual {
  display: grid;
  grid-template-columns: repeat(10, 1fr);
  gap: 5px;
  padding: 20px;
  background: #eef3f0;
}

.hash-cell {
  border: 1px solid #9ad4a9;
  background: #c8f7d3;
  border-radius: 4px;
  display: grid;
  place-items: center;
  font: 700 9px ui-monospace, monospace;
  color: #1f573e;
}

.hash-cell.hit {
  background: #d7ef72;
  border-color: var(--green);
}

.tool-visual {
  display: grid;
  place-items: center;
  background:
    radial-gradient(circle at 20% 20%, rgba(215, 239, 114, .6), transparent 28%),
    radial-gradient(circle at 80% 10%, rgba(30, 89, 61, .16), transparent 24%),
    linear-gradient(135deg, #fffdf8, #eef3df);
}

.tool-icon {
  width: 86px;
  height: 86px;
  border-radius: 24px;
  display: grid;
  place-items: center;
  color: white;
  background: var(--green);
  box-shadow: 0 18px 40px rgba(30, 89, 61, .25);
  font: 700 34px Georgia, serif;
}

.typing-visual {
  display: grid;
  place-items: center;
  background: #edf3ef;
}

.typing-visual .tool-icon {
  position: relative;
  z-index: 2;
  background: #327a82;
}

.typing-key {
  position: absolute;
  width: 34px;
  height: 34px;
  display: grid;
  place-items: center;
  border: 1px solid #c6c8be;
  border-bottom-width: 4px;
  border-radius: 7px;
  background: #fffdf8;
  color: var(--ink);
  font: 700 12px ui-monospace, monospace;
}

.typing-key.key-one { left: 21%; top: 28%; transform: rotate(-9deg); }
.typing-key.key-two { right: 20%; top: 24%; transform: rotate(8deg); }
.typing-key.key-three { right: 24%; bottom: 20%; transform: rotate(-5deg); }

.quiz-visual {
  background:
    radial-gradient(circle at 74% 20%, rgba(215, 239, 114, .5), transparent 28%),
    linear-gradient(135deg, #edf3ff, #e8f5ee);
}

.quiz-preview-card {
  position: absolute;
  left: 20%;
  top: 28px;
  width: 118px;
  height: 148px;
  padding: 13px;
  border: 1px solid rgba(255,255,255,.4);
  border-radius: 18px;
  background: linear-gradient(145deg, #2e65ed, #2d38aa);
  box-shadow: 0 18px 35px rgba(40,55,155,.22);
  color: white;
  transform: rotate(-5deg);
}

.quiz-preview-card span { font: 700 10px ui-monospace,monospace; opacity: .75; }
.quiz-preview-card strong { display: grid; height: 102px; place-items: center; font: 600 55px Georgia,serif; }
.quiz-preview-buzzer { position:absolute; z-index:2; right:23%; bottom:33px; width:72px; height:72px; display:grid; place-items:center; border:7px solid #e7f59a; border-radius:50%; background:var(--green); color:white; box-shadow:0 13px 28px rgba(30,89,61,.28); font-size:28px; font-weight:900; }
.quiz-preview-wave { position:absolute; right:17%; bottom:19px; width:112px; height:112px; border:1px solid rgba(30,89,61,.18); border-radius:50%; }
.quiz-preview-wave.wave-two { right:13%; bottom:4px; width:142px; height:142px; }
.portal-student-link { display:inline-block; margin:13px 0 0; color:var(--green); font-size:11px; font-weight:700; text-decoration:none; }
.portal-student-link:hover { text-decoration:underline; }

@media (max-width: 980px) {
  .topbar {
    height: auto;
    min-height: 76px;
    flex-wrap: wrap;
    gap: 12px;
    padding-top: 14px;
    padding-bottom: 14px;
  }

  .module-nav {
    order: 3;
    width: 100%;
    margin: 0;
    overflow-x: auto;
  }

  .portal-main {
    margin-left: 20px;
    margin-right: 20px;
  }

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

  .portal-card {
    min-height: 0;
  }
}

@media (max-width: 600px) {
  .module-nav a {
    padding: 7px 10px;
    white-space: nowrap;
  }

  .portal-main {
    padding-top: 46px;
  }

  .portal-hero h1 {
    font-size: 40px;
  }
}