:root {
  --bg: #0f172a;
  --card: #111827;
  --txt: #e5e7eb;
  --muted: #9ca3af;
  --brand: #f97316;
}

/* Reset + base */
* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: system-ui, Segoe UI, Roboto, Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--txt);
}

header {
  padding: 28px 20px 10px;
  font-weight: 700;
  font-size: 22px;
}

.wrap {
  max-width: 1000px;
  margin: 0 auto;
  padding: 18px;
}

/* Course grid */
.grid {
  display: grid;
  grid-template-columns: 1fr;   /* mobile: always single column */
  gap: 16px;
}

/* Cards */
.card {
  background: var(--card);
  border: 1px solid #1f2937;
  border-radius: 14px;
  padding: 16px;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.badge {
  font-weight: 800;
  color: #111827;
  background: var(--brand);
  border-radius: 999px;
  padding: 2px 10px;
  display: inline-block;
}

h3 {
  margin: 6px 0 2px;
  font-size: 18px;
}

p {
  margin: 0;
  color: var(--muted);
  font-size: 14px;
  line-height: 1.35;
}

.btn {
  display: inline-block;
  margin-top: 10px;
  padding: 10px 12px;
  border-radius: 10px;
  background: #14b8a6; /* teal accent */
  color: #111827;
  font-weight: 700;
  text-decoration: none;
  text-align: center;
  width: 100%; /* full-width for mobile tap targets */
}

/* Subheadings inside grid */
.subheading {
  display: block;
  grid-column: 1 / -1;
  margin: 24px 0 12px;
  font-weight: 800;
  font-size: 16px;
  color: var(--brand);
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

/* Footer */
footer {
  color: var(--muted);
  font-size: 12px;
  padding: 22px;
  text-align: center;
}

/* Hide sidebar by default (mobile-first) */
.sidebar { display: none; }

/* Desktop layout + sticky image */
@media (min-width:1024px){
  .layout{
    display:grid;
    grid-template-columns: 320px 1fr;
    gap:24px;
    align-items:start;
  }

  /* Sidebar: no fixed height; match the photo’s aspect ratio */
  .sidebar{
    display:block;
    position:sticky;
    top:24px;
    /* height:calc(100vh - 48px);  <-- remove this */
    aspect-ratio: 1501 / 3861;      /* exact ratio of the image */
    max-height: calc(100vh - 48px); /* cap so it fits in the viewport */
    border:1px solid #1f2937;
    border-radius:14px;
    overflow:hidden;                 /* chamfer clips the image */
    background:#0b1224;
  }

  .sidebar picture{
    display:block;
    width:100%;
    height:100%;
  }

  .sidebar img{
    display:block;
    width:100%;
    height:100%;          /* fill the aspect-ratio box */
    object-fit:contain;   /* no cropping, full tester visible */
    object-position:center top;
  }
}