:root {
  --paper: #fbfbfa;
  --surface: #ffffff;
  --well: #f5f5f2;
  --ink: #1a1a1a;
  --muted: #6b6b66;
  --faint: #9a9a93;
  --line: rgba(26, 26, 26, 0.12);
  --line-soft: rgba(26, 26, 26, 0.07);
  --accent: #0b6b62;
  --danger: #b42318;
  --mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;
  --radius: 12px;
  color-scheme: light;
  font-family: InterVariable, Inter, ui-sans-serif, system-ui, sans-serif;
  font-feature-settings: "cv02", "cv03", "cv04", "cv11", "ss01";
}

* {
  box-sizing: border-box;
}

html {
  min-height: 100%;
}

body {
  min-height: 100vh;
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: inherit;
  font-size: 16px;
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

button,
input {
  font: inherit;
  color: inherit;
}

button {
  border: 0;
}

::selection {
  background: var(--ink);
  color: var(--paper);
}

.app-shell {
  width: min(1080px, calc(100vw - 40px));
  margin: 0 auto;
  padding: 20px 0 80px;
}

/* ---------- Topbar ---------- */

.topbar {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto auto;
  gap: 24px;
  align-items: center;
  padding: 8px 0 32px;
  border-bottom: 1px solid var(--line-soft);
  margin-bottom: 32px;
}

.brand {
  display: flex;
  min-width: 0;
  align-items: center;
  gap: 12px;
  color: inherit;
  text-decoration: none;
}

.brand-mark {
  display: grid;
  width: 34px;
  height: 34px;
  flex: 0 0 auto;
  place-items: center;
  border-radius: 8px;
  background: var(--ink);
  color: var(--paper);
  font-family: var(--mono);
  font-size: 0.8125rem;
  font-weight: 600;
  letter-spacing: -0.03em;
}

.brand-title,
.brand-subtitle,
.token-box span,
.token-box small {
  display: block;
}

.brand-title {
  overflow: hidden;
  font-size: 0.9375rem;
  font-weight: 580;
  letter-spacing: -0.01em;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.brand-subtitle {
  color: var(--faint);
  font-family: var(--mono);
  font-size: 0.75rem;
  letter-spacing: 0.01em;
}

.topnav {
  display: flex;
  min-width: 0;
  gap: 24px;
  overflow-x: auto;
  scrollbar-width: none;
}

.topnav::-webkit-scrollbar {
  display: none;
}

.topnav button {
  position: relative;
  min-height: 32px;
  flex: 0 0 auto;
  background: transparent;
  color: var(--muted);
  cursor: pointer;
  padding: 0;
  font-size: 0.9375rem;
  font-weight: 500;
}

.topnav button:hover {
  color: var(--ink);
}

.topnav button[aria-current] {
  color: var(--ink);
  font-weight: 580;
}

.topnav button[aria-current]::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: -33px;
  height: 2px;
  background: var(--ink);
}

.topnav button:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
  border-radius: 2px;
}

.topbar-metrics {
  display: flex;
  gap: 28px;
}

.metric {
  min-width: 84px;
}

.metric-label {
  display: block;
  color: var(--faint);
  font-size: 0.75rem;
  font-weight: 500;
}

.metric-value {
  display: block;
  margin-top: 3px;
  font-family: var(--mono);
  font-size: 1.0625rem;
  font-weight: 600;
  letter-spacing: -0.02em;
  font-variant-numeric: tabular-nums;
}

/* ---------- Section labels & headings ---------- */

.eyebrow {
  margin: 0 0 14px;
  color: var(--accent);
  font-family: var(--mono);
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.catalog-copy h1,
.hero-copy h1 {
  max-width: 16ch;
  margin: 0;
  font-size: clamp(2.1rem, 4.5vw, 3.4rem);
  font-weight: 560;
  letter-spacing: -0.035em;
  line-height: 1.05;
  text-wrap: balance;
}

.catalog-copy p,
.hero-copy p,
.panel-head p,
.exam-list-card p,
.task p,
.flow-steps span {
  color: var(--muted);
  font-size: 1rem;
  line-height: 1.6;
  text-wrap: pretty;
}

.catalog-copy p,
.hero-copy p {
  max-width: 52ch;
  margin: 20px 0 0;
}

/* ---------- Catalog ---------- */

.catalog-shell {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(300px, 400px);
  gap: 56px;
  align-items: center;
  min-height: 440px;
}

.exam-list-card {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface);
  padding: 28px;
}

.exam-list-top,
.task-top,
.panel-head,
.command-panel-head,
.card-heading {
  display: flex;
  min-width: 0;
  align-items: flex-start;
  justify-content: space-between;
  gap: 16px;
}

.exam-list-card h2,
.card-heading h2,
.panel-head h2,
.task h3 {
  margin: 0;
  font-weight: 580;
  letter-spacing: -0.02em;
  text-wrap: balance;
}

.exam-list-card h2 {
  margin-top: 16px;
  font-size: 1.5rem;
}

.exam-score {
  font-family: var(--mono);
  font-size: 1.75rem;
  font-weight: 600;
  letter-spacing: -0.03em;
  line-height: 1;
  font-variant-numeric: tabular-nums;
}

.exam-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin: 22px 0 26px;
}

.exam-tags span {
  border: 1px solid var(--line);
  border-radius: 6px;
  color: var(--muted);
  font-family: var(--mono);
  font-size: 0.75rem;
  padding: 3px 8px;
}

.status-pill {
  display: inline-flex;
  align-items: center;
  border: 1px solid var(--line);
  border-radius: 5px;
  color: var(--muted);
  padding: 2px 8px;
  font-family: var(--mono);
  font-size: 0.71875rem;
  font-weight: 500;
  letter-spacing: 0.01em;
}

/* ---------- Buttons ---------- */

.primary,
form button {
  display: inline-flex;
  min-height: 40px;
  align-items: center;
  justify-content: center;
  border-radius: 9px;
  background: var(--ink);
  color: var(--paper);
  cursor: pointer;
  font-size: 0.9375rem;
  font-weight: 540;
  padding: 0 16px;
  transition: opacity 0.12s ease;
}

.primary {
  width: 100%;
}

.primary:hover,
form button:hover {
  opacity: 0.86;
}

.primary:focus-visible,
form button:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.primary:disabled,
form button:disabled {
  background: transparent;
  border: 1px solid var(--line);
  color: var(--faint);
  cursor: not-allowed;
}

form button {
  min-height: 38px;
  font-size: 0.875rem;
  padding: 0 14px;
}

/* ---------- Exam hero ---------- */

.hero {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(280px, 380px);
  gap: 48px;
  align-items: start;
  padding-bottom: 8px;
}

.hero-copy {
  padding-top: 8px;
}

.command-panel {
  display: grid;
  align-content: start;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--well);
  overflow: hidden;
}

.command-panel-head {
  align-items: center;
  padding: 12px 16px;
  border-bottom: 1px solid var(--line);
  color: var(--faint);
  font-family: var(--mono);
  font-size: 0.75rem;
  font-weight: 500;
}

.command-panel code {
  border: 0;
  border-radius: 0;
  border-top: 1px solid var(--line-soft);
  background: transparent;
  color: var(--ink);
  padding: 9px 16px;
}

.command-panel code:first-of-type {
  border-top: 0;
}

code {
  display: block;
  min-width: 0;
  overflow-wrap: anywhere;
  border-radius: 7px;
  background: var(--well);
  color: var(--ink);
  font-family: var(--mono);
  font-size: 0.8125rem;
  line-height: 1.5;
  padding: 7px 10px;
}

.inline-code {
  display: inline;
  border-radius: 4px;
  padding: 1px 5px;
  font-size: 0.875em;
  white-space: normal;
}

/* ---------- Flow steps ---------- */

.flow-card {
  margin-top: 64px;
}

.card-heading {
  align-items: baseline;
  margin-bottom: 4px;
}

.card-heading .eyebrow {
  margin: 0;
}

.flow-steps {
  display: grid;
  grid-template-columns: repeat(5, minmax(0, 1fr));
  gap: 28px;
  margin: 28px 0 0;
  padding: 0;
  list-style: none;
}

.flow-steps li {
  display: grid;
  align-content: start;
  gap: 8px;
  padding-top: 16px;
  border-top: 2px solid var(--ink);
  counter-increment: step;
}

.flow-steps li::before {
  content: counter(step, decimal-leading-zero);
  color: var(--faint);
  font-family: var(--mono);
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.02em;
}

.flow-steps strong {
  font-size: 0.9375rem;
  font-weight: 580;
  letter-spacing: -0.01em;
}

.flow-steps span {
  font-size: 0.875rem;
}

/* ---------- Workspace layout ---------- */

.layout {
  display: grid;
  grid-template-columns: 280px minmax(0, 1fr);
  gap: 48px;
  margin-top: 64px;
}

.side-panel {
  display: grid;
  align-content: start;
  gap: 36px;
}

.side-panel .card-heading {
  display: grid;
  justify-items: start;
  gap: 6px;
}

.side-panel .card-heading .eyebrow {
  margin: 0;
}

.side-panel .card-heading h2 {
  font-size: 1.125rem;
}

.exam-facts {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 20px;
  margin: 20px 0;
}

.exam-facts dt {
  color: var(--faint);
  font-size: 0.75rem;
  font-weight: 500;
}

.exam-facts dd {
  margin: 5px 0 0;
  font-family: var(--mono);
  font-size: 1.25rem;
  font-weight: 600;
  letter-spacing: -0.03em;
  font-variant-numeric: tabular-nums;
}

.token-box {
  display: grid;
  gap: 6px;
  margin-top: 18px;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: var(--surface);
  padding: 14px;
}

.token-box span {
  color: var(--faint);
  font-family: var(--mono);
  font-size: 0.6875rem;
  font-weight: 500;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.token-box code {
  background: var(--well);
  color: var(--accent);
  font-weight: 600;
}

.token-box small {
  color: var(--muted);
  font-size: 0.8125rem;
}

.rules {
  display: grid;
  gap: 12px;
  margin: 18px 0 0;
  padding: 0;
  list-style: none;
}

.rules li {
  position: relative;
  padding-left: 20px;
  color: var(--muted);
  font-size: 0.9375rem;
  line-height: 1.5;
}

.rules li::before {
  content: "—";
  position: absolute;
  left: 0;
  color: var(--faint);
}

/* ---------- Task board ---------- */

.task-panel {
  min-width: 0;
}

.panel-head {
  align-items: flex-end;
  margin-bottom: 24px;
}

.panel-head h2 {
  font-size: 1.375rem;
}

.panel-head p {
  max-width: 60ch;
  margin: 8px 0 0;
  font-size: 0.9375rem;
}

.progress-summary {
  display: grid;
  width: 168px;
  flex: 0 0 auto;
  gap: 8px;
  color: var(--muted);
  font-family: var(--mono);
  font-size: 0.75rem;
  text-align: right;
}

.progress-track {
  height: 4px;
  overflow: hidden;
  border-radius: 999px;
  background: var(--line-soft);
}

.progress-track span {
  display: block;
  height: 100%;
  border-radius: inherit;
  background: var(--accent);
  transition: width 0.35s ease;
}

.tasks {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
}

.task {
  display: grid;
  gap: 12px;
  min-width: 0;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface);
  padding: 18px;
}

.task.done {
  border-color: var(--accent);
}

.task.locked {
  background: transparent;
  border-style: dashed;
}

.min-w {
  min-width: 0;
}

.task-id {
  display: block;
  color: var(--faint);
  font-family: var(--mono);
  font-size: 0.75rem;
  font-weight: 500;
  letter-spacing: 0.01em;
}

.task h3 {
  margin-top: 5px;
  font-size: 1.0625rem;
}

.task-top strong {
  flex: 0 0 auto;
  color: var(--muted);
  font-family: var(--mono);
  font-size: 0.8125rem;
  font-weight: 600;
  font-variant-numeric: tabular-nums;
}

.task.done .task-top strong {
  color: var(--accent);
}

.task.done .task-top strong::after {
  content: " ✓";
}

.task p {
  min-height: 48px;
  margin: 0;
  font-size: 0.9375rem;
  line-height: 1.55;
}

.task-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  color: var(--faint);
  font-family: var(--mono);
  font-size: 0.71875rem;
}

.task-meta span {
  display: inline-flex;
}

.task-meta span + span::before {
  content: "·";
  margin-right: 8px;
}

.command-row {
  display: grid;
  gap: 5px;
}

.task code {
  font-size: 0.75rem;
  background: var(--well);
}

form {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 84px;
  gap: 8px;
  margin-top: 2px;
}

input {
  min-width: 0;
  min-height: 38px;
  border: 1px solid var(--line);
  border-radius: 9px;
  background: var(--surface);
  color: var(--ink);
  padding: 0 12px;
  font-family: var(--mono);
  font-size: 0.8125rem;
  transition: border-color 0.12s ease;
}

input::placeholder {
  font-family: InterVariable, Inter, sans-serif;
  color: var(--faint);
}

input:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(11, 107, 98, 0.12);
}

input:disabled {
  background: var(--well);
  color: var(--faint);
}

input.invalid {
  border-color: var(--danger);
  box-shadow: 0 0 0 3px rgba(180, 35, 24, 0.12);
}

.form-error,
.task-error {
  margin: 8px 0 0;
  color: var(--danger);
  font-size: 0.8125rem;
  line-height: 1.45;
}

.task-error {
  margin-top: 0;
  font-family: var(--mono);
}

/* ---------- Responsive ---------- */

@media (max-width: 980px) {
  .topbar {
    grid-template-columns: 1fr auto;
    grid-template-areas:
      "brand metrics"
      "nav nav";
    row-gap: 20px;
  }

  .brand {
    grid-area: brand;
  }

  .topbar-metrics {
    grid-area: metrics;
  }

  .topnav {
    grid-area: nav;
    gap: 20px;
  }

  .topnav button[aria-current]::after {
    display: none;
  }

  .catalog-shell,
  .hero,
  .layout {
    grid-template-columns: 1fr;
    gap: 40px;
  }

  .layout {
    margin-top: 48px;
  }

  .flow-steps {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 640px) {
  .app-shell {
    width: min(100vw - 28px, 1080px);
  }

  .catalog-copy h1,
  .hero-copy h1 {
    font-size: 2.2rem;
  }

  .tasks,
  .panel-head,
  .flow-steps {
    grid-template-columns: 1fr;
  }

  .panel-head {
    display: grid;
    gap: 16px;
  }

  .progress-summary {
    width: 100%;
    text-align: left;
  }

  .rules li,
  .catalog-copy p,
  .hero-copy p,
  .task p {
    font-size: 1rem;
  }

  form {
    grid-template-columns: 1fr;
  }

  input,
  .primary,
  form button {
    min-height: 44px;
    font-size: 1rem;
  }
}

@media (prefers-reduced-motion: reduce) {
  * {
    transition: none !important;
  }
}