/* Pages: home (hero, stats, path map), lesson, playground, schema, reference, certificate. */

/* ---------------------------------------------------------------- home: hero */
.hero {
  display: grid;
  grid-template-columns: minmax(0, 1.05fr) minmax(0, 1fr);
  gap: var(--s-6);
  align-items: center;
  padding-block: var(--s-5) var(--s-6);
}

/* One column that never outgrows the page, so a long eyebrow wraps instead of widening it. */
.hero-copy {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: var(--s-4);
  align-content: start;
}

.hero-title {
  font-size: clamp(2rem, 4.4vw, 3.3rem);
  font-weight: 800;
  line-height: var(--lh-display);
}

/* The answer the data gives back, in the site's gradient ink. */
.hero-title .hl {
  background-image: var(--text-gradient);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  padding-inline: 0.04em;
}

.hero-lead {
  max-width: 34em;
  font-size: var(--fs-md);
  color: var(--ink-2);
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: var(--s-3);
  margin-block-start: var(--s-2);
}

.hero-facts {
  display: flex;
  flex-wrap: wrap;
  gap: var(--s-2) var(--s-4);
  font-size: var(--fs-sm);
  color: var(--ink-3);
}

.hero-facts span {
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

.hero-facts svg {
  width: 16px;
  height: 16px;
  fill: none;
  stroke: currentColor;
  stroke-width: 1.8;
}

.hero-demo {
  position: relative;
}

.hero-demo .runner {
  box-shadow: var(--shadow-2);
}

.hero-demo-caption {
  margin-block-start: var(--s-2);
  font-size: var(--fs-xs);
  color: var(--ink-3);
  text-align: center;
}

/* ---------------------------------------------------------------- home: stats */
.stats {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: var(--s-3);
  margin-block: var(--s-2) var(--s-6);
}

.stat {
  display: grid;
  gap: 2px;
  padding: 14px 16px;
  border: 1px solid var(--rule);
  border-radius: var(--r-lg);
  background: color-mix(in srgb, var(--surface) 90%, transparent);
}

.stat-label {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: var(--fs-xs);
  font-weight: 600;
  color: var(--ink-3);
}

.stat-label svg {
  width: 15px;
  height: 15px;
  fill: none;
  stroke: currentColor;
  stroke-width: 2;
}

.stat-value {
  font-family: var(--font-display);
  font-size: var(--fs-xl);
  font-weight: 700;
  line-height: 1.3;
}

.stat-sub {
  font-size: var(--fs-xs);
  color: var(--ink-3);
}

.stat .bar {
  margin-block-start: 6px;
}

/* ---------------------------------------------------------------- home: path map */
.section-head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: var(--s-3);
  margin-block-end: var(--s-4);
}

.section-title {
  font-size: var(--fs-2xl);
}

.section-note {
  color: var(--ink-3);
  font-size: var(--fs-sm);
}

.path {
  display: grid;
  gap: var(--s-4);
}

.level {
  display: grid;
  grid-template-columns: 76px minmax(0, 1fr);
  gap: var(--s-4);
  padding: 20px 22px;
  border: 1px solid var(--rule);
  border-radius: var(--r-lg);
  background: color-mix(in srgb, var(--surface) 90%, transparent);
  transition: border-color var(--dur), box-shadow var(--dur);
}

.level.is-current {
  border-color: color-mix(in srgb, var(--accent) 45%, var(--rule));
  box-shadow: var(--shadow-glow);
}

.level.is-complete {
  border-color: color-mix(in srgb, var(--ok) 45%, var(--rule));
}

.level-number {
  display: grid;
  place-items: center;
  align-self: start;
  width: 64px;
  height: 64px;
  border-radius: 18px;
  background: var(--surface-2);
  border: 1px solid var(--rule);
  font-family: var(--font-display);
  font-size: 1.9rem;
  font-weight: 700;
  line-height: 1;
  color: var(--ink-2);
}

/* The level you are on wears the brand gradient, like the site's primary action. */
.level.is-current .level-number {
  background: var(--brand-gradient);
  border-color: transparent;
  color: var(--on-btn);
  box-shadow: 0 10px 30px -14px color-mix(in srgb, var(--btn-b) 80%, transparent);
}

.level.is-complete .level-number {
  background: var(--ok-soft);
  color: var(--ok);
}

.level-body {
  display: grid;
  gap: var(--s-3);
}

.level-head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: var(--s-2) var(--s-3);
}

.level-title {
  font-size: var(--fs-xl);
}

.level-subtitle {
  color: var(--ink-3);
  font-size: var(--fs-sm);
}

.level-progress {
  display: flex;
  align-items: center;
  gap: var(--s-3);
  font-size: var(--fs-xs);
  color: var(--ink-3);
}

.level-progress .bar {
  flex: 1;
  max-width: 260px;
}

.lessons {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
  gap: 8px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.lesson-link {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: 4px 10px;
  align-items: start;
  height: 100%;
  padding: 10px 12px;
  border: 1px solid var(--rule);
  border-radius: var(--r-sm);
  background: var(--paper);
  color: var(--ink);
  text-decoration: none;
  transition: border-color var(--dur-fast), background var(--dur-fast), transform var(--dur-fast);
}

.lesson-link:hover {
  border-color: var(--accent);
  background: var(--surface);
  color: var(--ink);
}

.lesson-status {
  display: grid;
  place-items: center;
  width: 22px;
  height: 22px;
  margin-top: 2px;
  border-radius: 50%;
  border: 1.5px solid var(--rule-strong);
  background: var(--surface);
}

.lesson-status svg {
  width: 13px;
  height: 13px;
  fill: none;
  stroke: currentColor;
  stroke-width: 3;
}

.lesson-link.is-done .lesson-status {
  border-color: var(--ok);
  background: var(--ok);
  color: var(--ok-ink);
}

.lesson-link.is-next {
  border-color: var(--accent);
  background: var(--accent-soft);
}

.lesson-link.is-next .lesson-status {
  border-color: var(--accent);
  background: var(--accent);
  box-shadow: 0 0 0 4px color-mix(in srgb, var(--accent) 20%, transparent);
}

.lesson-name {
  font-weight: 600;
  font-size: var(--fs-sm);
  line-height: 1.55;
}

.lesson-meta {
  grid-column: 2;
  display: flex;
  flex-wrap: wrap;
  gap: 4px 10px;
  font-size: var(--fs-2xs);
  color: var(--ink-3);
}

.home-tools {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: var(--s-3);
  margin-block-start: var(--s-6);
}

.tool-card {
  display: grid;
  gap: 6px;
  padding: 16px 18px;
  border: 1px solid var(--rule);
  border-radius: var(--r-lg);
  background: color-mix(in srgb, var(--surface) 90%, transparent);
  color: var(--ink);
  text-decoration: none;
  transition: border-color var(--dur), box-shadow var(--dur), transform var(--dur) var(--ease);
}

.tool-card:hover {
  border-color: color-mix(in srgb, var(--accent) 55%, var(--rule));
  box-shadow: var(--shadow-glow);
  transform: translateY(-3px);
  color: var(--ink);
}

.tool-card-title {
  display: flex;
  align-items: center;
  gap: 8px;
  font-weight: 700;
}

.tool-card-title svg {
  width: 18px;
  height: 18px;
  fill: none;
  stroke: var(--accent);
  stroke-width: 2;
}

.tool-card p {
  font-size: var(--fs-sm);
  color: var(--ink-2);
}

.backup {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--s-2);
  margin-block-start: var(--s-5);
  font-size: var(--fs-sm);
  color: var(--ink-3);
}

.sync-note {
  font-size: var(--fs-xs);
  color: var(--ink-3);
}

/* ---------------------------------------------------------------- lesson */
.lesson-page {
  display: grid;
  grid-template-columns: minmax(0, var(--content-width)) 260px;
  justify-content: center;
  gap: var(--s-7);
  max-width: var(--page-width);
  margin-inline: auto;
  padding-inline: var(--gutter);
  padding-block: var(--s-5) var(--s-8);
}

.lesson-main {
  min-width: 0;
}

.crumbs {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 6px;
  font-size: var(--fs-xs);
  color: var(--ink-3);
}

.crumbs a {
  color: var(--ink-2);
  text-decoration: none;
}

.crumbs a:hover {
  color: var(--accent);
}

.lesson-header {
  display: grid;
  gap: var(--s-3);
  padding-block-end: var(--s-4);
  margin-block-end: var(--s-2);
  border-bottom: 1px solid var(--rule);
}

.lesson-title {
  font-size: clamp(1.9rem, 3.6vw, 2.6rem);
}

.lesson-goal {
  display: flex;
  gap: 10px;
  align-items: flex-start;
  font-size: var(--fs-md);
  color: var(--ink-2);
}

.lesson-goal svg {
  flex-shrink: 0;
  width: 20px;
  height: 20px;
  margin-top: 6px;
  fill: none;
  stroke: var(--accent);
  stroke-width: 2;
}

.lesson-chips {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.lesson-problems {
  margin-block: var(--s-3);
}

.lesson-footer {
  display: grid;
  gap: var(--s-4);
  margin-block-start: var(--s-7);
  padding-block-start: var(--s-5);
  border-top: 1px solid var(--rule);
}

.complete-card {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--s-3);
  padding: 16px 18px;
  border: 1px solid var(--rule);
  border-radius: var(--r-md);
  background: var(--surface);
}

.complete-card.is-done {
  border-color: color-mix(in srgb, var(--ok) 50%, var(--rule));
  background: var(--ok-soft);
}

.complete-text {
  flex: 1 1 240px;
  display: grid;
  gap: 2px;
}

.complete-title {
  font-weight: 700;
}

.complete-sub {
  font-size: var(--fs-sm);
  color: var(--ink-2);
}

.lesson-nav {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--s-3);
}

.lesson-nav a {
  display: grid;
  gap: 2px;
  padding: 12px 14px;
  border: 1px solid var(--rule);
  border-radius: var(--r-md);
  background: var(--surface);
  color: var(--ink);
  text-decoration: none;
}

.lesson-nav a:hover {
  border-color: var(--accent);
  color: var(--ink);
}

.lesson-nav .is-next {
  text-align: end;
  grid-column: 2;
}

.lesson-nav-label {
  font-size: var(--fs-xs);
  color: var(--ink-3);
}

.lesson-nav-title {
  font-weight: 600;
}

.ask-lesson {
  display: grid;
  gap: var(--s-2);
}

/* Side rail */
.lesson-rail {
  position: sticky;
  top: calc(var(--topbar-height) + 20px);
  align-self: start;
  display: grid;
  gap: var(--s-4);
  max-height: calc(100vh - var(--topbar-height) - 40px);
  overflow-y: auto;
  padding-inline-end: 4px;
}

.rail-card {
  display: grid;
  gap: var(--s-2);
  padding: 14px;
  border: 1px solid var(--rule);
  border-radius: var(--r-md);
  background: var(--surface);
}

.rail-title {
  font-size: var(--fs-xs);
  font-weight: 700;
  color: var(--ink-3);
  letter-spacing: 0.03em;
}

.rail-progress-value {
  font-size: var(--fs-lg);
  font-weight: 700;
}

.outline {
  display: grid;
  gap: 2px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.outline a {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 5px 8px;
  border-radius: var(--r-sm);
  color: var(--ink-2);
  text-decoration: none;
  font-size: var(--fs-xs);
  line-height: 1.5;
}

.outline a:hover {
  background: var(--surface-2);
  color: var(--ink);
}

.outline-dot {
  flex-shrink: 0;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  border: 1.5px solid var(--rule-strong);
}

.outline-item.is-exercise .outline-dot {
  border-radius: 2px;
}

.outline-item.is-done .outline-dot {
  background: var(--ok);
  border-color: var(--ok);
}

.rail-toggle {
  display: none;
}

/* ---------------------------------------------------------------- playground */
.playground {
  display: grid;
  grid-template-columns: 300px minmax(0, 1fr);
  gap: var(--s-5);
  align-items: start;
}

.playground-side {
  position: sticky;
  top: calc(var(--topbar-height) + 20px);
  display: grid;
  gap: var(--s-3);
  max-height: calc(100vh - var(--topbar-height) - 40px);
  overflow-y: auto;
  padding-inline-end: 4px;
}

.playground-main {
  display: grid;
  gap: var(--s-4);
  min-width: 0;
}

.page-head {
  display: grid;
  gap: var(--s-2);
  margin-block-end: var(--s-4);
}

.page-title {
  font-size: var(--fs-2xl);
}

.page-lead {
  color: var(--ink-2);
  max-width: 44em;
}

.samples {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.history-list {
  display: grid;
  gap: 6px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.history-item {
  display: block;
  width: 100%;
  padding: 8px 10px;
  border: 1px solid var(--rule);
  border-radius: var(--r-sm);
  background: var(--surface);
  color: var(--ink-2);
  font-family: var(--font-mono);
  font-size: 0.76rem;
  text-align: left;
  direction: ltr;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  cursor: pointer;
}

.history-item:hover {
  border-color: var(--accent);
  color: var(--ink);
}

.user-objects {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

/* ---------------------------------------------------------------- schema page */
.schema-page {
  display: grid;
  gap: var(--s-5);
}

.schema-erd {
  border: 1px solid var(--rule);
  border-radius: var(--r-lg);
  overflow: hidden;
  background: var(--surface);
}

.schema-columns-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: var(--s-3);
  align-items: start;
}

.schema-columns-grid .schema-list {
  display: contents;
}

/* ---------------------------------------------------------------- reference */
.reference-tools {
  position: sticky;
  top: calc(var(--topbar-height) + 8px);
  z-index: 5;
  display: flex;
  flex-wrap: wrap;
  gap: var(--s-2);
  padding-block: 10px;
  background: var(--paper);
}

.reference-tools input {
  flex: 1 1 260px;
}

.reference-section {
  display: grid;
  gap: var(--s-3);
  margin-block: var(--s-5);
}

.reference-section-title {
  font-size: var(--fs-xl);
}

.reference-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: var(--s-3);
}

.ref-card {
  display: grid;
  gap: var(--s-2);
  align-content: start;
  padding: 14px 16px;
  border: 1px solid var(--rule);
  border-radius: var(--r-md);
  background: var(--surface);
}

.ref-card-head {
  display: flex;
  align-items: baseline;
  gap: var(--s-2);
}

.ref-card-title {
  font-weight: 700;
}

.ref-card .code-static {
  font-size: 0.82rem;
  padding: 8px 10px;
}

.ref-card .md {
  font-size: var(--fs-sm);
  color: var(--ink-2);
}

.ref-card .btn-row {
  justify-content: flex-end;
}

.empty-state {
  padding: var(--s-6);
  text-align: center;
  color: var(--ink-3);
}

/* ---------------------------------------------------------------- certificate */
.certificate {
  position: relative;
  display: grid;
  gap: var(--s-4);
  justify-items: center;
  padding: clamp(24px, 6vw, 56px);
  border: 1px solid var(--rule-strong);
  border-radius: var(--r-lg);
  background-color: var(--surface);
  background-image:
    linear-gradient(var(--paper-grid) 1px, transparent 1px),
    linear-gradient(90deg, var(--paper-grid) 1px, transparent 1px);
  background-size: 22px 22px;
  text-align: center;
  box-shadow: var(--shadow-2);
}

.certificate::before {
  content: "";
  position: absolute;
  inset: 12px;
  border: 1.5px solid var(--accent-line);
  border-radius: calc(var(--r-lg) - 6px);
  pointer-events: none;
}

.certificate-kicker {
  font-size: var(--fs-sm);
  font-weight: 700;
  letter-spacing: 0.05em;
  color: var(--accent);
}

.certificate-name {
  font-size: clamp(2rem, 6vw, 3.4rem);
  font-weight: 800;
  line-height: var(--lh-display);
  padding-inline: 0.2em;
  background-image: var(--text-gradient);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.certificate-text {
  max-width: 36em;
  font-size: var(--fs-md);
  color: var(--ink-2);
}

.certificate-stats {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: var(--s-2) var(--s-5);
  font-size: var(--fs-sm);
  color: var(--ink-2);
}

.certificate-stats strong {
  font-family: var(--font-mono);
  color: var(--ink);
}

.certificate-foot {
  font-size: var(--fs-xs);
  color: var(--ink-3);
}

.certificate-form {
  display: flex;
  flex-wrap: wrap;
  gap: var(--s-2);
  justify-content: center;
  margin-block-start: var(--s-4);
}

.certificate-form input {
  width: min(100%, 320px);
}

/* ---------------------------------------------------------------- responsive */
.lesson-inline-tools {
  display: none;
}

@media (max-width: 1100px) {
  .lesson-page {
    grid-template-columns: minmax(0, 1fr);
    gap: var(--s-4);
  }

  .lesson-rail {
    display: none;
  }

  .lesson-inline-tools {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: var(--s-2);
  }
}

@media (max-width: 900px) {
  .hero {
    grid-template-columns: minmax(0, 1fr);
  }

  .playground {
    grid-template-columns: minmax(0, 1fr);
  }

  .playground-side {
    position: static;
    max-height: none;
    order: 2;
  }

  .stats {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 560px) {
  .level {
    grid-template-columns: minmax(0, 1fr);
    padding: 16px;
  }

  .level-number {
    width: 48px;
    height: 48px;
    font-size: 1.4rem;
    border-radius: 12px;
  }

  .lesson-nav {
    grid-template-columns: minmax(0, 1fr);
  }

  .lesson-nav .is-next {
    grid-column: 1;
  }
}