:root {
  --void: #030609;
  --void-2: #08090f;
  --void-3: #0f1018;
  --coral: #FF6B35;
  --gold: #C9A227;
  --cyan: #00F0FF;
  --ice: #EAF1FC;
  --steel: #7A94B4;
  --ink: rgba(3, 6, 9, 0.78);
  --line: rgba(234, 241, 252, 0.12);
  --line-strong: rgba(201, 162, 39, 0.38);
  --shadow-tight: 0 18px 44px rgba(0, 0, 0, 0.42);
  --font-display: "Bebas Neue", Impact, sans-serif;
  --font-body: "Inter", system-ui, sans-serif;
  --font-mono: "JetBrains Mono", monospace;
  --ease-premium: 0.25s cubic-bezier(.16, 1, .3, 1);
}

* {
  box-sizing: border-box;
}

html {
  background: var(--void);
  scroll-behavior: smooth;
}

body.ai-mastery {
  margin: 0;
  min-height: 100vh;
  background:
    radial-gradient(circle at 18% 2%, rgba(201, 162, 39, 0.16), transparent 30rem),
    radial-gradient(circle at 92% 10%, rgba(255, 107, 53, 0.12), transparent 28rem),
    linear-gradient(180deg, var(--void), var(--void-2) 48%, var(--void));
  color: var(--ice);
  font-family: var(--font-body);
  line-height: 1.65;
}

body.ai-mastery::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  opacity: 0.065;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 512 512' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='grain'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.72' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23grain)' opacity='1'/%3E%3C/svg%3E");
  background-size: 220px 220px;
}

img {
  display: block;
  max-width: 100%;
  height: auto;
}

a {
  color: inherit;
}

a,
button {
  transition:
    color var(--ease-premium),
    border-color var(--ease-premium),
    background var(--ease-premium),
    transform var(--ease-premium),
    opacity var(--ease-premium);
}

a:focus-visible,
button:focus-visible {
  outline: 2px solid var(--coral);
  outline-offset: 4px;
}

.skip-link {
  position: fixed;
  top: 0.75rem;
  left: 0.75rem;
  z-index: 20;
  transform: translateY(-160%);
  background: var(--coral);
  color: var(--ice);
  padding: 0.7rem 0.9rem;
  border-radius: 0.375rem;
  font-weight: 800;
  text-decoration: none;
}

.skip-link:focus {
  transform: translateY(0);
}

.course-topbar {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 1rem clamp(1.5rem, 5vw, 4rem);
  border-bottom: 1px solid var(--line);
  background: rgba(3, 6, 9, 0.88);
  backdrop-filter: blur(18px);
}

.course-brand {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  color: var(--ice);
  font-family: var(--font-body);
  font-weight: 900;
  letter-spacing: 0;
  text-decoration: none;
}

.course-brand span:last-child {
  color: var(--coral);
}

.brand-rule {
  width: 0.16rem;
  height: 1.25rem;
  background: var(--coral);
  border-radius: 0.25rem;
}

.course-nav {
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 0.5rem;
}

.course-nav a {
  border: 1px solid transparent;
  border-radius: 0.375rem;
  color: var(--steel);
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.08em;
  padding: 0.45rem 0.62rem;
  text-decoration: none;
  text-transform: uppercase;
}

.course-nav a:hover {
  border-color: var(--line-strong);
  color: var(--ice);
}

.course-shell {
  position: relative;
  z-index: 1;
  max-width: 1200px;
  margin-inline: auto;
  padding: clamp(2rem, 5vw, 4rem) clamp(1.5rem, 5vw, 4rem) clamp(5rem, 10vw, 9rem);
}

.course-loading {
  min-height: 50vh;
  display: grid;
  place-items: center;
  color: var(--steel);
  font-family: var(--font-mono);
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.course-kicker {
  margin: 0 0 0.85rem;
  color: var(--gold);
  font-family: var(--font-mono);
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.18em;
  text-transform: uppercase;
}

.btn-primary,
.btn-ghost {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 2.8rem;
  border-radius: 0.375rem;
  padding: 0.78rem 1rem;
  font-family: var(--font-body);
  font-size: 0.88rem;
  font-weight: 800;
  text-decoration: none;
}

.btn-primary {
  border: 1px solid var(--coral);
  background: var(--coral);
  color: var(--ice);
  box-shadow: 0 14px 34px rgba(255, 107, 53, 0.2);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 18px 46px rgba(255, 107, 53, 0.28);
}

.btn-ghost {
  border: 1px solid rgba(255, 107, 53, 0.52);
  background: transparent;
  color: var(--coral);
}

.btn-ghost:hover {
  background: rgba(255, 107, 53, 0.08);
  color: var(--ice);
}

.course-hero,
.portfolio-hero,
.day-hero {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1.5rem;
  align-items: stretch;
  padding-block: clamp(3rem, 7vw, 6rem);
}

.course-hero h1,
.portfolio-hero h1,
.day-hero h1 {
  margin: 0;
  max-width: 12ch;
  color: var(--ice);
  font-family: var(--font-display);
  font-size: clamp(4rem, 11vw, 9rem);
  font-weight: 400;
  letter-spacing: 0;
  line-height: 0.86;
}

.day-hero h1 {
  max-width: 13ch;
  font-size: clamp(3.2rem, 8vw, 7rem);
}

.course-hero p,
.portfolio-hero p,
.day-hero p {
  max-width: 68ch;
  color: var(--steel);
  font-size: clamp(1rem, 1.7vw, 1.18rem);
}

.course-hero img,
.portfolio-hero img,
.day-hero img {
  border: 1px solid var(--line-strong);
  border-radius: 0.75rem;
  box-shadow: var(--shadow-tight);
  object-fit: cover;
  aspect-ratio: 16 / 9;
}

.course-actions,
.day-meta,
.day-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  align-items: center;
  margin-top: 1.3rem;
}

.day-meta span {
  border: 1px solid var(--line);
  border-radius: 0.375rem;
  color: var(--steel);
  font-family: var(--font-mono);
  font-size: 0.73rem;
  padding: 0.42rem 0.55rem;
  text-transform: uppercase;
}

.progress-panel,
.week-card,
.side-panel,
.source-card,
.finish-day-card,
.portfolio-artifact,
.mastery-ladder article,
.fast-track-card,
.start-panel {
  border: 1px solid var(--line);
  border-radius: 0.75rem;
  background:
    linear-gradient(180deg, rgba(234, 241, 252, 0.035), rgba(234, 241, 252, 0)),
    rgba(8, 9, 15, 0.86);
  box-shadow: var(--shadow-tight);
}

.progress-panel {
  display: grid;
  gap: 1rem;
  padding: clamp(1.1rem, 3vw, 1.5rem);
  margin-bottom: clamp(2rem, 5vw, 3rem);
}

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

.stat-value {
  display: block;
  color: var(--ice);
  font-family: var(--font-mono);
  font-size: clamp(1.8rem, 4vw, 3rem);
  font-weight: 700;
  line-height: 1;
}

.stat-label {
  color: var(--steel);
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

.progress-track {
  overflow: hidden;
  height: 0.52rem;
  border-radius: 0.375rem;
  background: rgba(122, 148, 180, 0.18);
}

.progress-fill {
  width: 0;
  height: 100%;
  border-radius: 0.375rem;
  background: linear-gradient(90deg, var(--coral), var(--gold));
}

.phase-band {
  margin-top: clamp(2.2rem, 5vw, 4.5rem);
}

.phase-head {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: 1rem;
  border-bottom: 1px solid var(--line-strong);
  padding-bottom: 0.8rem;
}

.phase-head h2,
.resource-section h2,
.finish-day-card h2,
.side-panel h2,
.lesson-main h2,
.start-panel h2 {
  margin: 0;
  color: var(--ice);
  font-size: clamp(1.4rem, 3vw, 2rem);
  letter-spacing: 0;
  line-height: 1.1;
}

.week-grid,
.source-grid,
.portfolio-grid,
.fast-track-grid,
.start-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 18rem), 1fr));
  gap: 1rem;
}

.week-card {
  display: grid;
  gap: 1rem;
  overflow: hidden;
  padding: 0;
}

.week-card img {
  width: 100%;
  aspect-ratio: 16 / 9;
  object-fit: cover;
  border-bottom: 1px solid var(--line);
}

.week-card-body {
  padding: 1rem;
}

.week-card h3 {
  margin: 0.25rem 0 0.55rem;
  color: var(--ice);
  font-size: 1.05rem;
  line-height: 1.25;
}

.week-card p,
.source-card p,
.side-panel p,
.portfolio-artifact p,
.mastery-ladder p,
.fast-track-card p,
.start-panel p {
  color: var(--steel);
}

.day-pills {
  display: grid;
  grid-template-columns: repeat(5, minmax(0, 1fr));
  gap: 0.35rem;
  margin-top: 0.8rem;
}

.day-pill {
  display: inline-flex;
  min-height: 2.15rem;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--line);
  border-radius: 0.375rem;
  color: var(--steel);
  font-family: var(--font-mono);
  font-size: 0.76rem;
  text-decoration: none;
}

.day-pill:hover,
.day-pill.is-complete {
  border-color: var(--line-strong);
  color: var(--ice);
  background: rgba(201, 162, 39, 0.08);
}

.lesson-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1.25rem;
  align-items: start;
}

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

.lesson-main {
  display: grid;
  gap: 1.35rem;
}

.lesson-main p {
  margin: 0;
  color: var(--ice);
  font-size: 1.03rem;
}

.lesson-diagram {
  margin: 0;
  border: 1px solid var(--line);
  border-radius: 0.75rem;
  overflow: hidden;
  background: var(--void-2);
}

.lesson-diagram figcaption {
  padding: 0.75rem 1rem;
  color: var(--steel);
  font-size: 0.9rem;
}

.lesson-steps {
  display: grid;
  gap: 0.9rem;
  margin: 0;
  padding-left: 1.2rem;
}

.lesson-steps li {
  color: var(--ice);
}

.lesson-side {
  display: grid;
  gap: 1rem;
}

.side-panel,
.source-card,
.portfolio-artifact,
.fast-track-card,
.start-panel {
  padding: 1rem;
}

.token-list {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem;
}

.token-list span {
  border: 1px solid rgba(255, 107, 53, 0.34);
  border-radius: 0.375rem;
  color: var(--coral);
  font-family: var(--font-mono);
  font-size: 0.72rem;
  padding: 0.26rem 0.42rem;
}

.mastery-ladder {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 16rem), 1fr));
  gap: 1rem;
  margin-block: 2rem;
}

.mastery-ladder article {
  padding: 1rem;
}

.mastery-ladder span,
.source-meta,
.artifact-index {
  color: var(--gold);
  font-family: var(--font-mono);
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
}

.resource-section {
  display: grid;
  gap: 1rem;
  margin-block: 2rem;
}

.source-card h3,
.portfolio-artifact h3,
.fast-track-card h3 {
  margin: 0.45rem 0 0.45rem;
  color: var(--ice);
  line-height: 1.25;
}

.source-card a {
  color: var(--cyan);
  font-family: var(--font-mono);
  font-size: 0.78rem;
  text-decoration: none;
}

.source-card a:hover {
  color: var(--ice);
}

.finish-day-card {
  display: grid;
  gap: 1rem;
  align-items: center;
  margin-block: 2rem;
  padding: 1rem;
}

.day-nav {
  justify-content: space-between;
}

.portfolio-grid {
  margin-top: 2rem;
}

.fast-track-card[data-complete="true"] {
  border-color: var(--line-strong);
  background:
    linear-gradient(180deg, rgba(201, 162, 39, 0.08), rgba(234, 241, 252, 0)),
    rgba(8, 9, 15, 0.9);
}

.fast-track-card button {
  width: 100%;
  margin-top: 0.8rem;
  cursor: pointer;
}

.start-grid {
  margin-top: 2rem;
}

.auth-page {
  display: grid;
  min-height: 100vh;
  place-items: center;
  padding: 1.5rem;
}

.auth-card {
  width: min(100%, 26rem);
  border: 1px solid var(--line-strong);
  border-radius: 0.75rem;
  background:
    linear-gradient(180deg, rgba(234, 241, 252, 0.04), rgba(234, 241, 252, 0)),
    rgba(8, 9, 15, 0.92);
  box-shadow: var(--shadow-tight);
  padding: clamp(1.4rem, 5vw, 2rem);
}

.auth-card h1 {
  margin: 1rem 0 0.7rem;
  color: var(--ice);
  font-family: var(--font-display);
  font-size: clamp(3.8rem, 16vw, 5.7rem);
  font-weight: 400;
  line-height: 0.86;
}

.auth-card p {
  color: var(--steel);
}

.auth-card form {
  display: grid;
  gap: 0.8rem;
  margin-top: 1.4rem;
}

.auth-card input {
  width: 100%;
  border: 1px solid var(--line);
  border-radius: 0.375rem;
  background: var(--void-3);
  color: var(--ice);
  font: inherit;
  padding: 0.9rem 1rem;
}

.auth-card input:focus {
  outline: 2px solid var(--coral);
  outline-offset: 4px;
}

.auth-error {
  border: 1px solid rgba(255, 107, 53, 0.45);
  border-radius: 0.5rem;
  color: var(--coral);
  padding: 0.7rem;
}

@media (min-width: 768px) {
  .course-hero,
  .portfolio-hero,
  .day-hero {
    grid-template-columns: minmax(0, 0.95fr) minmax(18rem, 0.72fr);
  }

  .progress-panel {
    grid-template-columns: 1fr auto;
  }

  .progress-stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .finish-day-card {
    grid-template-columns: 1fr auto;
  }
}

@media (min-width: 1024px) {
  .lesson-grid {
    grid-template-columns: minmax(0, 1fr) 20rem;
  }
}

@media (max-width: 767px) {
  body.ai-mastery::before {
    opacity: 0.04;
  }

  .course-topbar {
    position: static;
    align-items: flex-start;
    flex-direction: column;
  }

  .course-nav {
    justify-content: flex-start;
  }

  .day-nav,
  .course-actions {
    align-items: stretch;
    flex-direction: column;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    animation-duration: 0.001ms;
    animation-iteration-count: 1;
    transition-duration: 0.001ms;
  }
}