:root {
  --bg: #f5f6f0;
  --panel: #ffffff;
  --ink: #1f2328;
  --muted: #5d6470;
  --line: #d8dde6;
  --accent: #0b6d4f;
  --accent-soft: #e8f5ef;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: "IBM Plex Sans", "Segoe UI", system-ui, sans-serif;
  color: var(--ink);
  background:
    radial-gradient(1200px 500px at 90% -10%, #d5efe2 0%, transparent 70%),
    radial-gradient(900px 400px at -10% 110%, #e7e5cf 0%, transparent 65%),
    var(--bg);
}

.app {
  min-height: 100vh;
  display: grid;
  grid-template-columns: 320px minmax(0, 1fr);
  gap: 12px;
  padding: 12px;
}

.panel {
  border: 1px solid var(--line);
  border-radius: 14px;
  background: var(--panel);
  box-shadow: 0 4px 20px rgba(10, 25, 20, 0.05);
}

.sidebar {
  display: flex;
  flex-direction: column;
  min-height: calc(100vh - 24px);
}

.sidebar-header {
  padding: 14px;
  border-bottom: 1px solid var(--line);
  background: linear-gradient(180deg, #f8fff8, #ffffff);
}

.sidebar-header h1 {
  margin: 0;
  font-size: 18px;
}

.sidebar-title-row {
  display: flex;
  align-items: center;
  gap: 8px;
  margin: 0 0 10px;
}

.github-link {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 28px;
  border: 1px solid var(--line);
  border-radius: 8px;
  color: #111827;
  text-decoration: none;
  background: #fff;
}

.github-link:hover {
  background: #f3f4f6;
}

#search {
  width: 100%;
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 10px 12px;
  font-size: 14px;
}

.problem-list {
  overflow: auto;
  padding: 8px;
}

.problem-item {
  display: block;
  width: 100%;
  text-align: left;
  border: 0;
  border-radius: 10px;
  padding: 10px;
  margin: 4px 0;
  background: transparent;
  cursor: pointer;
}

.problem-item:hover {
  background: #f5f8fc;
}

.problem-item.active {
  background: var(--accent-soft);
  outline: 1px solid #b9e6cf;
}

.problem-id {
  font-weight: 700;
  font-size: 13px;
}

.problem-sub {
  color: var(--muted);
  font-size: 12px;
  margin-top: 2px;
}

.content {
  display: grid;
  grid-template-rows: minmax(280px, auto) minmax(280px, 1fr);
  gap: 12px;
  min-height: calc(100vh - 24px);
}

.overview {
  padding: 14px;
}

.overview-top {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 12px;
  margin-bottom: 8px;
}

#problemTitle {
  margin: 0;
  font-size: 26px;
}

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

.overview-flow {
  display: block;
  border-top: 1px solid var(--line);
}

.section-line {
  padding: 14px 2px 14px 2px;
  border-bottom: 1px solid var(--line);
}

.section-line h3 {
  margin: 0 0 8px;
  font-size: 15px;
  letter-spacing: 0.01em;
}

.text-block {
  white-space: pre-wrap;
  line-height: 1.4;
  font-size: 13px;
  color: #252b35;
}

.notes {
  display: flex;
  flex-direction: column;
  min-height: 0;
}

.tabs {
  padding: 8px;
  border-bottom: 1px solid var(--line);
}

.tab {
  border: 1px solid var(--line);
  background: #fff;
  border-radius: 8px;
  padding: 7px 10px;
  margin-right: 6px;
  cursor: pointer;
}

.tab.active {
  background: var(--accent-soft);
  border-color: #b9e6cf;
}

.tab-panel {
  display: none;
  min-height: 0;
  overflow: auto;
  padding: 10px;
}

.tab-panel.active {
  display: block;
}

.note-raw {
  line-height: 1.45;
  font-size: 14px;
}

.computations pre.note-raw {
  margin: 0;
  white-space: pre-wrap;
  line-height: 1.35;
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 12px;
}

.computations {
  display: grid;
  gap: 10px;
}

.comp-item {
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 10px;
}

.comp-kind {
  font-size: 12px;
  color: var(--muted);
}

@media (max-width: 1050px) {
  .app {
    grid-template-columns: 1fr;
  }
  .sidebar {
    min-height: 250px;
  }
  .content {
    min-height: auto;
    grid-template-rows: auto auto;
  }
  #problemTitle {
    font-size: 22px;
  }
}