/* ========================================
   Navigation
   ======================================== */

.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  height: var(--nav-height);
  background-color: rgba(11, 15, 26, 0.88);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border-color);
}

.nav__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}

.nav__brand {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  font-size: var(--text-lg);
  font-weight: 700;
  color: var(--text-primary);
  text-decoration: none;
  letter-spacing: -0.01em;
}

.nav__brand:hover {
  color: var(--accent-primary);
}

.nav__brand-icon {
  width: 1.75rem;
  height: 1.75rem;
  color: var(--accent-secondary);
  filter: drop-shadow(0 0 6px rgba(52, 211, 153, 0.3));
}

.nav__links {
  display: flex;
  align-items: center;
  gap: var(--space-xl);
}

.nav__link {
  position: relative;
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--text-muted);
  text-decoration: none;
  transition: color var(--transition-base);
  padding-bottom: 2px;
}

.nav__link::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 0;
  height: 1px;
  background-color: var(--accent-primary);
  transition: width var(--transition-base);
}

.nav__link:hover {
  color: var(--text-primary);
}

.nav__link:hover::after {
  width: 100%;
}

.nav__toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  padding: var(--space-sm);
}

.nav__toggle-bar {
  display: block;
  width: 22px;
  height: 2px;
  background-color: var(--text-primary);
  border-radius: 1px;
  transition: transform var(--transition-base), opacity var(--transition-base);
}

@media (max-width: 48em) {
  .nav__toggle {
    display: flex;
  }

  .nav__links {
    display: none;
    position: absolute;
    top: var(--nav-height);
    left: 0;
    right: 0;
    flex-direction: column;
    padding: var(--space-lg);
    background-color: rgba(11, 15, 26, 0.96);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border-bottom: 1px solid var(--border-color);
    gap: var(--space-sm);
  }

  .nav__links--open {
    display: flex;
  }

  .nav__link {
    font-size: var(--text-base);
    padding: var(--space-sm) 0;
    color: var(--text-secondary);
  }
}

/* Toggle active state */
.nav__toggle--active .nav__toggle-bar:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.nav__toggle--active .nav__toggle-bar:nth-child(2) {
  opacity: 0;
}

.nav__toggle--active .nav__toggle-bar:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* ========================================
   Hero
   ======================================== */

.hero {
  position: relative;
  display: flex;
  align-items: center;
  min-height: 88vh;
  padding-top: var(--nav-height);
  overflow: hidden;
}

/* Ambient glow background — replaces the cliche grid */
.hero__bg {
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse 60% 50% at 15% 45%, rgba(56, 189, 248, 0.07) 0%, transparent 70%),
    radial-gradient(ellipse 50% 40% at 75% 25%, rgba(52, 211, 153, 0.05) 0%, transparent 60%),
    radial-gradient(ellipse 40% 50% at 50% 80%, rgba(167, 139, 250, 0.03) 0%, transparent 50%);
  pointer-events: none;
}

/* Subtle noise texture overlay */
.hero__bg::after {
  content: '';
  position: absolute;
  inset: 0;
  opacity: 0.015;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 256 256' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
  background-size: 200px 200px;
  pointer-events: none;
}

/* Decorative shield watermark */
.hero__watermark {
  position: absolute;
  right: -5%;
  top: 50%;
  transform: translateY(-50%);
  width: 40vw;
  max-width: 500px;
  height: auto;
  opacity: 0.025;
  pointer-events: none;
  color: var(--accent-primary);
}

.hero__content {
  position: relative;
  max-width: 44rem;
}

.hero__badge {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-xs) var(--space-md);
  margin-bottom: var(--space-xl);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  font-weight: 400;
  color: var(--accent-secondary);
  background-color: rgba(52, 211, 153, 0.08);
  border: 1px solid rgba(52, 211, 153, 0.15);
  border-radius: 9999px;
  letter-spacing: 0.04em;
  animation: hero-fade-up 0.6s cubic-bezier(0.16, 1, 0.3, 1) 0.1s both;
}

.hero__title {
  margin-bottom: var(--space-lg);
  animation: hero-fade-up 0.6s cubic-bezier(0.16, 1, 0.3, 1) 0.2s both;
}

.hero__title-accent {
  background: linear-gradient(135deg, var(--accent-primary) 0%, #7dd3fc 50%, var(--accent-secondary) 100%);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero__description {
  font-size: var(--text-lg);
  line-height: 1.7;
  margin-bottom: var(--space-2xl);
  max-width: 38rem;
  animation: hero-fade-up 0.6s cubic-bezier(0.16, 1, 0.3, 1) 0.35s both;
}

.hero__cta {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-md);
  animation: hero-fade-up 0.6s cubic-bezier(0.16, 1, 0.3, 1) 0.5s both;
}

/* ========================================
   Buttons
   ======================================== */

.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  padding: 0.75rem 1.5rem;
  font-size: var(--text-sm);
  font-weight: 600;
  border-radius: var(--radius-md);
  transition: all var(--transition-base);
  text-decoration: none;
  position: relative;
}

.btn--primary {
  color: #0b0f1a;
  background: linear-gradient(135deg, var(--accent-primary) 0%, #7dd3fc 100%);
  box-shadow: 0 0 20px rgba(56, 189, 248, 0.15);
}

.btn--primary:hover {
  color: #0b0f1a;
  box-shadow: 0 0 30px rgba(56, 189, 248, 0.25);
  transform: translateY(-1px);
}

.btn--secondary {
  color: var(--text-primary);
  background-color: var(--bg-tertiary);
  border: 1px solid var(--border-color);
}

.btn--secondary:hover {
  background-color: var(--border-color-hover);
  color: var(--text-primary);
  border-color: var(--border-color-hover);
  transform: translateY(-1px);
}

.btn--accent {
  color: #0b0f1a;
  background: linear-gradient(135deg, var(--accent-warm) 0%, #fcd34d 100%);
  font-weight: 700;
  box-shadow: 0 0 20px rgba(251, 191, 36, 0.12);
}

.btn--accent:hover {
  color: #0b0f1a;
  box-shadow: 0 0 30px rgba(251, 191, 36, 0.22);
  transform: translateY(-1px);
}

/* ========================================
   Cards — base
   ======================================== */

.card {
  display: flex;
  flex-direction: column;
  padding: var(--space-lg);
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  transition:
    border-color var(--transition-base),
    transform var(--transition-slow),
    box-shadow var(--transition-slow);
  text-decoration: none;
  color: inherit;
  position: relative;
  overflow: hidden;
}

/* Colored top-edge accent on hover */
.card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: var(--card-accent, var(--accent-primary));
  opacity: 0;
  transition: opacity var(--transition-base);
}

.card:hover {
  border-color: var(--border-color-hover);
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
  color: inherit;
}

.card:hover::before {
  opacity: 1;
}

.card__icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 2.75rem;
  height: 2.75rem;
  margin-bottom: var(--space-md);
  border-radius: var(--radius-md);
  transition: transform var(--transition-base);
}

.card:hover .card__icon {
  transform: scale(1.05);
}

.card__icon--blue {
  background-color: rgba(56, 189, 248, 0.1);
  color: var(--accent-primary);
}

.card__icon--green {
  background-color: rgba(52, 211, 153, 0.1);
  color: var(--accent-secondary);
}

.card__icon--amber {
  background-color: rgba(251, 191, 36, 0.1);
  color: var(--accent-warm);
}

.card__icon--red {
  background-color: rgba(248, 113, 113, 0.1);
  color: var(--accent-danger);
}

/* Set card accent color based on icon color */
.card:has(.card__icon--blue) { --card-accent: var(--accent-primary); }
.card:has(.card__icon--green) { --card-accent: var(--accent-secondary); }
.card:has(.card__icon--amber) { --card-accent: var(--accent-warm); }
.card:has(.card__icon--red) { --card-accent: var(--accent-danger); }

.card__title {
  font-size: var(--text-lg);
  font-weight: 700;
  margin-bottom: var(--space-xs);
  letter-spacing: -0.01em;
}

.card__org {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--text-muted);
  margin-bottom: var(--space-sm);
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.card__description {
  font-size: var(--text-sm);
  color: var(--text-secondary);
  flex: 1;
  line-height: 1.6;
}

.card__footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-top: var(--space-md);
  padding-top: var(--space-md);
  border-top: 1px solid var(--border-color);
}

.card__link-text {
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--accent-primary);
}

.card:hover .card__link-text {
  color: var(--accent-primary-hover);
}

.card__arrow {
  transition: transform var(--transition-base);
  color: var(--text-muted);
}

.card:hover .card__arrow {
  transform: translateX(4px);
  color: var(--accent-primary);
}

/* ========================================
   Cards — Labs variant (colored left border)
   ======================================== */

.card--lab {
  border-left: 3px solid var(--card-accent, var(--border-color));
  border-radius: var(--radius-sm) var(--radius-lg) var(--radius-lg) var(--radius-sm);
}

.card--lab::before {
  display: none;
}

.card--lab.card--beginner { --card-accent: var(--accent-secondary); }
.card--lab.card--intermediate { --card-accent: var(--accent-primary); }
.card--lab.card--all { --card-accent: var(--accent-purple); }

/* Badge for difficulty levels */
.badge {
  display: inline-flex;
  align-items: center;
  gap: 0.25rem;
  padding: 0.125rem 0.625rem;
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  font-weight: 500;
  border-radius: 9999px;
  letter-spacing: 0.02em;
}

.badge--beginner {
  background-color: rgba(52, 211, 153, 0.1);
  color: var(--accent-secondary);
}

.badge--intermediate {
  background-color: rgba(56, 189, 248, 0.1);
  color: var(--accent-primary);
}

.badge--advanced {
  background-color: rgba(251, 191, 36, 0.1);
  color: var(--accent-warm);
}

.badge--all {
  background-color: rgba(167, 139, 250, 0.1);
  color: var(--accent-purple);
}

/* ========================================
   YouTube Facade
   ======================================== */

.youtube-facade {
  position: relative;
  width: 100%;
  padding-bottom: 56.25%;
  background-color: var(--bg-tertiary);
  border-radius: var(--radius-lg);
  overflow: hidden;
  cursor: pointer;
  border: 1px solid var(--border-color);
}

.youtube-facade__thumb {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.youtube-facade__play {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: 4.5rem;
  height: 3.25rem;
  background-color: rgba(255, 0, 0, 0.85);
  border-radius: var(--radius-lg);
  transition: background-color var(--transition-fast), transform var(--transition-base);
}

.youtube-facade__play::after {
  content: '';
  position: absolute;
  top: 50%;
  left: 55%;
  transform: translate(-50%, -50%);
  border-style: solid;
  border-width: 0.625rem 0 0.625rem 1rem;
  border-color: transparent transparent transparent #fff;
}

.youtube-facade:hover .youtube-facade__play {
  background-color: rgba(255, 0, 0, 1);
  transform: translate(-50%, -50%) scale(1.08);
}

.youtube-facade iframe {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  border: 0;
}

/* ========================================
   About Section
   ======================================== */

.about__content {
  display: grid;
  gap: var(--space-3xl);
  align-items: start;
}

@media (min-width: 48em) {
  .about__content {
    grid-template-columns: 1.1fr 0.9fr;
  }
}

.about__text p {
  margin-bottom: var(--space-lg);
  line-height: 1.7;
}

.about__text p:last-of-type {
  margin-bottom: 0;
}

/* Stats bar */
.about__stats {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-md);
  margin-top: var(--space-2xl);
  padding-top: var(--space-2xl);
  border-top: 1px solid var(--border-color);
}

.about__stat {
  text-align: center;
}

.about__stat-number {
  display: block;
  font-family: var(--font-mono);
  font-size: var(--text-3xl);
  font-weight: 700;
  color: var(--accent-primary);
  line-height: 1;
  margin-bottom: var(--space-xs);
}

.about__stat-label {
  font-size: var(--text-xs);
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

/* Credentials */
.about__credentials {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
  margin-top: var(--space-xl);
}

.credential-tag {
  display: inline-flex;
  align-items: center;
  gap: var(--space-xs);
  padding: 0.3rem var(--space-md);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  font-weight: 400;
  color: var(--accent-secondary);
  background-color: rgba(52, 211, 153, 0.06);
  border: 1px solid rgba(52, 211, 153, 0.12);
  border-radius: 9999px;
  letter-spacing: 0.03em;
}

/* ========================================
   Newsletter
   ======================================== */

.newsletter {
  text-align: center;
}

.newsletter__features {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: var(--space-lg);
  margin-top: var(--space-lg);
  margin-bottom: var(--space-xl);
}

.newsletter__feature {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  font-size: var(--text-sm);
  color: var(--text-secondary);
}

.newsletter__feature svg {
  color: var(--accent-secondary);
  flex-shrink: 0;
}

.newsletter__form {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: var(--space-sm);
  max-width: 28rem;
  margin-inline: auto;
  margin-top: var(--space-lg);
}

.newsletter__input {
  flex: 1;
  min-width: 12rem;
  padding: 0.75rem 1rem;
  font-size: var(--text-base);
  font-family: var(--font-body);
  color: var(--text-primary);
  background-color: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.newsletter__input::placeholder {
  color: var(--text-muted);
}

.newsletter__input:focus {
  outline: none;
  border-color: var(--accent-primary);
  box-shadow: 0 0 0 3px rgba(56, 189, 248, 0.1);
}

.newsletter__note {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-xs);
  margin-top: var(--space-md);
  font-size: var(--text-sm);
  color: var(--text-muted);
}

.newsletter__note svg {
  flex-shrink: 0;
}

/* ========================================
   Footer
   ======================================== */

.footer {
  padding-block: var(--space-3xl);
  border-top: 1px solid var(--border-color);
  background-color: var(--bg-primary);
}

.footer__inner {
  display: flex;
  flex-direction: column;
  gap: var(--space-2xl);
}

.footer__top {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-start;
  justify-content: space-between;
  gap: var(--space-2xl);
}

.footer__brand {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  font-weight: 700;
  font-size: var(--text-base);
  color: var(--text-primary);
  text-decoration: none;
  margin-bottom: var(--space-sm);
}

.footer__brand svg {
  color: var(--accent-secondary);
  width: 1.25rem;
  height: 1.25rem;
}

.footer__tagline {
  font-size: var(--text-sm);
  color: var(--text-muted);
  max-width: 30ch;
}

.footer__nav {
  display: flex;
  gap: var(--space-xl);
  flex-wrap: wrap;
}

.footer__nav-link {
  font-size: var(--text-sm);
  color: var(--text-muted);
  text-decoration: none;
  transition: color var(--transition-fast);
}

.footer__nav-link:hover {
  color: var(--text-primary);
}

.footer__bottom {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-md);
  padding-top: var(--space-xl);
  border-top: 1px solid var(--border-color);
}

.footer__copy {
  font-size: var(--text-sm);
  color: var(--text-muted);
}

.footer__links {
  display: flex;
  align-items: center;
  gap: var(--space-lg);
}

.footer__link {
  font-size: var(--text-sm);
  color: var(--text-muted);
  text-decoration: none;
  transition: color var(--transition-fast);
}

.footer__link:hover {
  color: var(--text-primary);
}

/* ========================================
   YouTube channel CTA (About section)
   ======================================== */

.about__yt-cta {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  margin-top: var(--space-xl);
  padding: var(--space-lg);
  background-color: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  text-decoration: none;
  color: inherit;
  transition: border-color var(--transition-base), transform var(--transition-base);
}

.about__yt-cta:hover {
  border-color: var(--border-color-hover);
  transform: translateY(-2px);
  color: inherit;
}

.about__yt-icon {
  flex-shrink: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 3rem;
  height: 3rem;
  background-color: rgba(248, 113, 113, 0.1);
  border-radius: var(--radius-md);
  color: var(--accent-danger);
}

.about__yt-text {
  flex: 1;
}

.about__yt-title {
  font-size: var(--text-sm);
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 2px;
}

.about__yt-desc {
  font-size: var(--text-xs);
  color: var(--text-muted);
}

.about__yt-arrow {
  color: var(--text-muted);
  transition: transform var(--transition-base), color var(--transition-base);
}

.about__yt-cta:hover .about__yt-arrow {
  transform: translateX(3px);
  color: var(--accent-primary);
}