@import url("https://fonts.googleapis.com/css2?family=Sora:wght@500;700;800&family=Space+Grotesk:wght@400;500;700&display=swap");

:root {
  --bg-1: #ffffff;
  --bg-2: #f7f9ff;
  --ink: #0f1b33;
  --muted: #5e6f8f;
  --accent: #4c6fff;
  --line: rgba(134, 160, 209, 0.35);
  --card: #ffffff;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: "Space Grotesk", sans-serif;
  color: var(--ink);
  background: #ffffff;
}

.page-bg {
  position: fixed;
  inset: 0;
  pointer-events: none;
  background:
    radial-gradient(circle at 12% 8%, rgba(95, 158, 255, 0.2) 0%, rgba(95, 158, 255, 0) 35%),
    radial-gradient(circle at 88% 4%, rgba(130, 120, 255, 0.06) 0%, rgba(255, 111, 71, 0) 38%);
}

.dsa-shell {
  max-width: 1160px;
  margin: 0 auto;
  padding: 20px;
  display: grid;
  gap: 12px;
  position: relative;
  z-index: 1;
}

.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 16px;
  backdrop-filter: blur(10px);
}

.topbar {
  padding: 12px 16px;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.brand {
  text-decoration: none;
  color: var(--ink);
  font-family: "Sora", sans-serif;
  font-weight: 800;
  font-size: 1.25rem;
}

nav { display: flex; gap: 10px; align-items: center; }

nav a, button {
  border: 0;
  border-radius: 12px;
  padding: 9px 12px;
  text-decoration: none;
  background: var(--accent);
  color: #fff;
  font-weight: 700;
  cursor: pointer;
}

.hero { padding: 16px; }

.eyebrow {
  margin: 0;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: #4f74d1;
  font-weight: 700;
  font-size: 0.78rem;
}

.hero h1 {
  margin: 8px 0;
  font-family: "Sora", sans-serif;
}

.hero p { margin: 0; color: var(--muted); }

.filters {
  padding: 12px;
  display: grid;
  grid-template-columns: 180px 1fr;
  gap: 10px;
}

label {
  display: grid;
  gap: 5px;
  color: #cfddf8;
  font-size: 0.9rem;
}

select, input, textarea, pre {
  border: 1px solid #3e6195;
  border-radius: 10px;
  background: #f8fbff;
  color: #1d3760;
  padding: 10px;
}

.problem-list {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 10px;
}

.problem-card {
  padding: 14px;
  display: grid;
  gap: 8px;
}

.problem-card h3 {
  margin: 0;
  font-family: "Sora", sans-serif;
  font-size: 1rem;
}

.tag-row { display: flex; gap: 8px; flex-wrap: wrap; }

.tag {
  display: inline-flex;
  border-radius: 999px;
  padding: 4px 8px;
  font-size: 0.75rem;
  background: rgba(255, 255, 255, 0.1);
  border: 1px solid #4f6d9d;
}

.tag.easy { color: #89f2bf; }
.tag.medium { color: #ffd67e; }
.tag.hard { color: #ff9a9a; }

.problem-card a {
  justify-self: start;
  text-decoration: none;
  border-radius: 10px;
  padding: 8px 10px;
  color: #fff;
  background: var(--accent);
  font-weight: 700;
}

.solve-grid,
.question-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1.1fr);
  gap: 10px;
}

.statement, .editor-panel { padding: 14px; min-height: 0; }
.link-panel { padding: 14px; }

.full-width {
  grid-column: 1 / -1;
}

.link-panel h2 {
  margin: 0;
  font-family: "Sora", sans-serif;
}

.link-panel p {
  color: #d7e5ff;
}

.statement h2, .statement h3 {
  margin: 8px 0;
  font-family: "Sora", sans-serif;
}

.statement p { color: #d7e5ff; }

.statement ul { margin: 0; color: #d7e5ff; }

.statement pre {
  white-space: pre-wrap;
  margin: 0;
}

.example-box {
  border: 1px solid #3b5f95;
  border-radius: 10px;
  padding: 10px;
  margin-bottom: 8px;
  background: rgba(8, 16, 31, 0.7);
}

.toolbar {
  display: flex;
  align-items: end;
  gap: 8px;
  flex-wrap: wrap;
  margin-bottom: 8px;
}

.pair-controls {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 8px;
  margin-bottom: 8px;
}

#codeEditor {
  width: 100%;
  min-height: 340px;
  resize: vertical;
  font-family: "SFMono-Regular", Menlo, Consolas, monospace;
  font-size: 13px;
}

#submitSummary {
  white-space: pre-wrap;
  margin: 8px 0;
  font-family: "SFMono-Regular", Menlo, Consolas, monospace;
}

#testResults {
  display: grid;
  gap: 6px;
}

.test-item {
  border: 1px solid #3d6299;
  border-radius: 10px;
  padding: 8px;
  background: rgba(8, 16, 31, 0.75);
}

.test-item.pass { border-color: #2f9a6b; }
.test-item.fail { border-color: #ba4c4c; }

.test-item p { margin: 0 0 4px; font-size: 0.85rem; color: #d4e3ff; }

.empty { color: var(--muted); }

@media (max-width: 980px) {
  .solve-grid, .question-grid { grid-template-columns: 1fr; }
}

@media (max-width: 760px) {
  .dsa-shell { padding: 14px; }
  .topbar { flex-direction: column; align-items: flex-start; gap: 8px; }
  nav { flex-wrap: wrap; }
  .filters { grid-template-columns: 1fr; }
  .pair-controls { grid-template-columns: 1fr; }
}