*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

:root {
  --color-bg: #FFFFFF;
  --color-bg-secondary: #F9F9F9;
  --color-text-primary: #0A0A0A;
  --color-text-secondary: #6B6B6B;
  --color-border: #E5E5E5;
  --color-accent: #0066FF;
  --color-accent-hover: #0052CC;
  --font: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --max-width: 1120px;
  --nav-height: 64px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --color-bg: #0A0A0A;
    --color-bg-secondary: #141414;
    --color-text-primary: #F5F5F5;
    --color-text-secondary: #888888;
    --color-border: #222222;
    --color-accent: #3385FF;
    --color-accent-hover: #5599FF;
  }
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font);
  background-color: var(--color-bg);
  color: var(--color-text-primary);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

img, svg {
  display: block;
  max-width: 100%;
}

a {
  color: var(--color-accent);
  text-decoration: none;
}

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

ul, ol {
  list-style: none;
}

button {
  font-family: var(--font);
  cursor: pointer;
  border: none;
  background: none;
}

/* ─── NAV ─────────────────────────────────────────────────── */

.nav {
  position: sticky;
  top: 0;
  z-index: 100;
  height: var(--nav-height);
  background-color: var(--color-bg);
  border-bottom: 0.5px solid var(--color-border);
  display: flex;
  align-items: center;
}

.nav__inner {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav__logo {
  font-size: 15px;
  font-weight: 600;
  color: var(--color-text-primary);
  letter-spacing: -0.01em;
  text-decoration: none;
}

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

.nav__links {
  display: flex;
  align-items: center;
  gap: 32px;
}

.nav__link {
  font-size: 14px;
  color: var(--color-text-secondary);
  text-decoration: none;
  transition: color 0.15s ease;
}

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

.nav__link--active {
  color: var(--color-text-primary);
  font-weight: 500;
}

.nav__cta {
  font-size: 13px;
  font-weight: 500;
  color: var(--color-bg);
  background-color: var(--color-text-primary);
  padding: 8px 16px;
  border-radius: 8px;
  text-decoration: none;
  transition: opacity 0.15s ease;
}

.nav__cta:hover {
  color: var(--color-bg);
  opacity: 0.8;
}

/* ─── LAYOUT CONTAINER ────────────────────────────────────── */

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

/* ─── HERO ────────────────────────────────────────────────── */

.hero {
  padding: 96px 0 80px;
  border-bottom: 0.5px solid var(--color-border);
}

.hero__eyebrow {
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--color-text-secondary);
  margin-bottom: 24px;
}

.hero__heading {
  font-size: clamp(36px, 5vw, 56px);
  font-weight: 600;
  line-height: 1.1;
  letter-spacing: -0.03em;
  color: var(--color-text-primary);
  max-width: 720px;
  margin-bottom: 24px;
}

.hero__subheading {
  font-size: 18px;
  line-height: 1.6;
  color: var(--color-text-secondary);
  max-width: 560px;
  margin-bottom: 40px;
}

.hero__actions {
  display: flex;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 14px;
  font-weight: 500;
  padding: 10px 20px;
  border-radius: 8px;
  text-decoration: none;
  transition: opacity 0.15s ease, background-color 0.15s ease;
  white-space: nowrap;
}

.btn--primary {
  background-color: var(--color-accent);
  color: #FFFFFF;
}

.btn--primary:hover {
  color: #FFFFFF;
  background-color: var(--color-accent-hover);
  opacity: 1;
}

.btn--secondary {
  background-color: transparent;
  color: var(--color-text-primary);
  border: 0.5px solid var(--color-border);
}

.btn--secondary:hover {
  color: var(--color-text-primary);
  border-color: var(--color-text-secondary);
}

/* ─── METRICS STRIP ───────────────────────────────────────── */

.metrics {
  border-bottom: 0.5px solid var(--color-border);
  padding: 48px 0;
}

.metrics__grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 0;
}

.metric {
  padding: 16px 32px 16px 0;
  border-right: 0.5px solid var(--color-border);
}

.metric:first-child {
  padding-left: 0;
}

.metric:last-child {
  border-right: none;
  padding-right: 0;
  padding-left: 32px;
}

.metric:not(:first-child):not(:last-child) {
  padding-left: 32px;
}

.metric__value {
  font-size: 32px;
  font-weight: 600;
  letter-spacing: -0.03em;
  color: var(--color-text-primary);
  line-height: 1.1;
  margin-bottom: 6px;
}

.metric__label {
  font-size: 13px;
  color: var(--color-text-secondary);
  line-height: 1.4;
}

/* ─── SECTION LABEL ───────────────────────────────────────── */

.section-label {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-bottom: 40px;
}

.section-label__text {
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--color-text-secondary);
  white-space: nowrap;
}

.section-label__line {
  flex: 1;
  height: 0.5px;
  background-color: var(--color-border);
}

/* ─── FILTER TABS ─────────────────────────────────────────── */

.filter-tabs {
  display: flex;
  align-items: center;
  gap: 4px;
  margin-bottom: 40px;
  flex-wrap: wrap;
}

.filter-tab {
  font-size: 13px;
  font-weight: 500;
  color: var(--color-text-secondary);
  background-color: transparent;
  border: 0.5px solid var(--color-border);
  border-radius: 8px;
  padding: 7px 14px;
  cursor: pointer;
  transition: color 0.15s ease, border-color 0.15s ease, background-color 0.15s ease;
}

.filter-tab:hover {
  color: var(--color-text-primary);
  border-color: var(--color-text-secondary);
}

.filter-tab--active {
  color: var(--color-accent);
  border-color: var(--color-accent);
  background-color: transparent;
}

/* ─── SECTION ─────────────────────────────────────────────── */

.section {
  padding: 72px 0;
  border-bottom: 0.5px solid var(--color-border);
}

.section:last-of-type {
  border-bottom: none;
}

/* ─── CASE STUDY CARD GRID ────────────────────────────────── */

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

.card {
  display: flex;
  flex-direction: column;
  border: 0.5px solid var(--color-border);
  border-radius: 12px;
  overflow: hidden;
  text-decoration: none;
  color: var(--color-text-primary);
  background-color: var(--color-bg);
  transition: border-color 0.2s ease;
}

.card:hover {
  border-color: var(--color-text-secondary);
  color: var(--color-text-primary);
}

.card__image {
  width: 100%;
  aspect-ratio: 16 / 9;
  background-color: var(--color-bg-secondary);
  border-bottom: 0.5px solid var(--color-border);
  overflow: hidden;
}

.card__image img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.card__body {
  padding: 24px;
  display: flex;
  flex-direction: column;
  flex: 1;
}

.card__tags {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin-bottom: 12px;
}

.tag {
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--color-text-secondary);
  border: 0.5px solid var(--color-border);
  border-radius: 4px;
  padding: 3px 8px;
}

.card__title {
  font-size: 18px;
  font-weight: 600;
  letter-spacing: -0.02em;
  line-height: 1.3;
  margin-bottom: 8px;
  color: var(--color-text-primary);
}

.card__description {
  font-size: 14px;
  color: var(--color-text-secondary);
  line-height: 1.6;
  margin-bottom: 20px;
  flex: 1;
}

.card__metrics {
  display: flex;
  gap: 24px;
  padding-top: 16px;
  border-top: 0.5px solid var(--color-border);
}

.card__metric-value {
  font-size: 20px;
  font-weight: 600;
  letter-spacing: -0.02em;
  color: var(--color-text-primary);
  line-height: 1.1;
}

.card__metric-label {
  font-size: 11px;
  color: var(--color-text-secondary);
  margin-top: 2px;
}

/* ─── SKILLS GRID ─────────────────────────────────────────── */

.skills-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1px;
  background-color: var(--color-border);
  border: 0.5px solid var(--color-border);
  border-radius: 12px;
  overflow: hidden;
}

.skill-cell {
  background-color: var(--color-bg);
  padding: 28px 24px;
}

.skill-cell__icon {
  font-size: 20px;
  margin-bottom: 12px;
  line-height: 1;
}

.skill-cell__title {
  font-size: 14px;
  font-weight: 600;
  color: var(--color-text-primary);
  margin-bottom: 8px;
  letter-spacing: -0.01em;
}

.skill-cell__items {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.skill-cell__item {
  font-size: 13px;
  color: var(--color-text-secondary);
  line-height: 1.4;
}

/* ─── ABOUT SECTION ───────────────────────────────────────── */

.about {
  display: grid;
  grid-template-columns: 2fr 1fr;
  gap: 80px;
  align-items: start;
}

.about__content {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.about__heading {
  font-size: clamp(28px, 3vw, 40px);
  font-weight: 600;
  letter-spacing: -0.03em;
  line-height: 1.15;
  color: var(--color-text-primary);
}

.about__body {
  font-size: 16px;
  color: var(--color-text-secondary);
  line-height: 1.75;
}

.about__body p + p {
  margin-top: 16px;
}

.about__sidebar {
  display: flex;
  flex-direction: column;
  gap: 32px;
}

.about__sidebar-block {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.about__sidebar-label {
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--color-text-secondary);
}

.about__sidebar-item {
  font-size: 14px;
  color: var(--color-text-primary);
  line-height: 1.5;
}

.about__sidebar-item + .about__sidebar-item {
  border-top: 0.5px solid var(--color-border);
  padding-top: 10px;
}

/* ─── FOOTER ──────────────────────────────────────────────── */

.footer {
  border-top: 0.5px solid var(--color-border);
  padding: 40px 0;
}

.footer__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 16px;
}

.footer__copy {
  font-size: 13px;
  color: var(--color-text-secondary);
}

.footer__links {
  display: flex;
  gap: 24px;
}

.footer__link {
  font-size: 13px;
  color: var(--color-text-secondary);
  text-decoration: none;
  transition: color 0.15s ease;
}

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

/* ─── CASE STUDY PAGE ─────────────────────────────────────── */

.cs-hero {
  padding: 72px 0 56px;
  border-bottom: 0.5px solid var(--color-border);
}

.cs-hero__back {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 13px;
  color: var(--color-text-secondary);
  text-decoration: none;
  margin-bottom: 32px;
  transition: color 0.15s ease;
}

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

.cs-hero__back svg {
  display: inline;
}

.cs-hero__tags {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin-bottom: 20px;
}

.cs-hero__heading {
  font-size: clamp(32px, 4.5vw, 52px);
  font-weight: 600;
  letter-spacing: -0.03em;
  line-height: 1.1;
  color: var(--color-text-primary);
  max-width: 840px;
  margin-bottom: 16px;
}

.cs-hero__subheading {
  font-size: 18px;
  color: var(--color-text-secondary);
  line-height: 1.6;
  max-width: 640px;
  margin-bottom: 40px;
}

.cs-hero__meta {
  display: flex;
  gap: 40px;
  flex-wrap: wrap;
}

.cs-hero__meta-item {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.cs-hero__meta-label {
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--color-text-secondary);
}

.cs-hero__meta-value {
  font-size: 14px;
  color: var(--color-text-primary);
  font-weight: 500;
}

/* ─── TL;DR STRIP ─────────────────────────────────────────── */

.tldr {
  border-bottom: 0.5px solid var(--color-border);
  padding: 40px 0;
  background-color: var(--color-bg-secondary);
}

.tldr__inner {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 40px;
  align-items: start;
}

.tldr__label {
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--color-text-secondary);
  padding-top: 2px;
  white-space: nowrap;
}

.tldr__items {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 32px;
}

.tldr__item-title {
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--color-text-secondary);
  margin-bottom: 6px;
}

.tldr__item-text {
  font-size: 14px;
  color: var(--color-text-primary);
  line-height: 1.55;
}

/* ─── CASE STUDY BODY LAYOUT ──────────────────────────────── */

.cs-body {
  padding: 72px 0;
}

.cs-layout {
  display: grid;
  grid-template-columns: 200px 1fr;
  gap: 72px;
  align-items: start;
}

.cs-sidebar {
  position: sticky;
  top: calc(var(--nav-height) + 24px);
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.cs-sidebar__link {
  font-size: 13px;
  color: var(--color-text-secondary);
  text-decoration: none;
  padding: 6px 0;
  border-left: 2px solid transparent;
  padding-left: 12px;
  transition: color 0.15s ease, border-color 0.15s ease;
  line-height: 1.4;
}

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

.cs-sidebar__link--active {
  color: var(--color-accent);
  border-left-color: var(--color-accent);
}

.cs-content {
  display: flex;
  flex-direction: column;
  gap: 64px;
}

.cs-section {
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.cs-section__heading {
  font-size: 22px;
  font-weight: 600;
  letter-spacing: -0.02em;
  color: var(--color-text-primary);
  padding-bottom: 16px;
  border-bottom: 0.5px solid var(--color-border);
}

.cs-section__text {
  font-size: 15px;
  color: var(--color-text-secondary);
  line-height: 1.75;
}

.cs-section__text p + p {
  margin-top: 16px;
}

.cs-section__text strong {
  color: var(--color-text-primary);
  font-weight: 600;
}

/* ─── INSIGHT BLOCKS ──────────────────────────────────────── */

.insight-block {
  border: 0.5px solid var(--color-border);
  border-radius: 8px;
  padding: 20px 24px;
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 16px;
  align-items: start;
}

.insight-block__icon {
  font-size: 18px;
  line-height: 1.5;
}

.insight-block__label {
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--color-text-secondary);
  margin-bottom: 6px;
}

.insight-block__text {
  font-size: 14px;
  color: var(--color-text-primary);
  line-height: 1.6;
}

/* ─── RESULT CARDS ────────────────────────────────────────── */

.result-cards {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px;
}

.result-card {
  border: 0.5px solid var(--color-border);
  border-radius: 12px;
  padding: 24px;
}

.result-card__value {
  font-size: 36px;
  font-weight: 600;
  letter-spacing: -0.03em;
  color: var(--color-text-primary);
  line-height: 1;
  margin-bottom: 8px;
}

.result-card__label {
  font-size: 13px;
  color: var(--color-text-secondary);
  line-height: 1.4;
}

/* ─── LESSONS LIST ────────────────────────────────────────── */

.lessons-list {
  display: flex;
  flex-direction: column;
  gap: 0;
}

.lesson-item {
  display: grid;
  grid-template-columns: 32px 1fr;
  gap: 16px;
  padding: 20px 0;
  border-bottom: 0.5px solid var(--color-border);
  align-items: start;
}

.lesson-item:first-child {
  border-top: 0.5px solid var(--color-border);
}

.lesson-item__number {
  font-size: 12px;
  font-weight: 600;
  color: var(--color-text-secondary);
  letter-spacing: 0.04em;
  padding-top: 2px;
}

.lesson-item__text {
  font-size: 15px;
  color: var(--color-text-primary);
  line-height: 1.6;
}

.lesson-item__text strong {
  display: block;
  font-weight: 600;
  margin-bottom: 4px;
}

/* ─── NEXT CASE FOOTER ────────────────────────────────────── */

.next-case {
  border-top: 0.5px solid var(--color-border);
  padding: 56px 0;
}

.next-case__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.next-case__label {
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--color-text-secondary);
  margin-bottom: 8px;
}

.next-case__title {
  font-size: 24px;
  font-weight: 600;
  letter-spacing: -0.02em;
  color: var(--color-text-primary);
}

.next-case__arrow {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 48px;
  height: 48px;
  border: 0.5px solid var(--color-border);
  border-radius: 50%;
  color: var(--color-text-primary);
  text-decoration: none;
  flex-shrink: 0;
  transition: border-color 0.15s ease, background-color 0.15s ease;
}

.next-case__arrow:hover {
  border-color: var(--color-text-primary);
  background-color: var(--color-text-primary);
  color: var(--color-bg);
}

.next-case__link {
  text-decoration: none;
  color: var(--color-text-primary);
}

.next-case__link:hover .next-case__title {
  color: var(--color-accent);
}

/* ─── RESPONSIVE ──────────────────────────────────────────── */

@media (max-width: 768px) {
  .nav__links {
    display: none;
  }

  .hero {
    padding: 56px 0 48px;
  }

  .hero__subheading {
    font-size: 16px;
  }

  .metrics__grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 1px;
    background-color: var(--color-border);
    border: 0.5px solid var(--color-border);
    border-radius: 8px;
    overflow: hidden;
  }

  .metric {
    background-color: var(--color-bg);
    padding: 20px;
    border-right: none;
  }

  .metric:first-child,
  .metric:not(:first-child):not(:last-child),
  .metric:last-child {
    padding: 20px;
  }

  .work-grid {
    grid-template-columns: 1fr;
  }

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

  .about {
    grid-template-columns: 1fr;
    gap: 40px;
  }

  .footer__inner {
    flex-direction: column;
    align-items: flex-start;
  }

  .cs-hero {
    padding: 48px 0 40px;
  }

  .cs-hero__meta {
    gap: 24px;
  }

  .tldr__inner {
    grid-template-columns: 1fr;
    gap: 20px;
  }

  .tldr__items {
    grid-template-columns: 1fr;
    gap: 20px;
  }

  .cs-layout {
    grid-template-columns: 1fr;
    gap: 40px;
  }

  .cs-sidebar {
    position: static;
    flex-direction: row;
    flex-wrap: wrap;
    gap: 8px;
    border-bottom: 0.5px solid var(--color-border);
    padding-bottom: 24px;
  }

  .cs-sidebar__link {
    border-left: none;
    border-bottom: 2px solid transparent;
    padding-left: 0;
    padding-bottom: 4px;
    font-size: 12px;
  }

  .cs-sidebar__link--active {
    border-left-color: transparent;
    border-bottom-color: var(--color-accent);
  }

  .result-cards {
    grid-template-columns: 1fr;
  }

  .next-case__title {
    font-size: 18px;
  }
}

@media (max-width: 480px) {
  .skills-grid {
    grid-template-columns: 1fr;
  }

  .metrics__grid {
    grid-template-columns: 1fr;
  }

  .hero__actions {
    flex-direction: column;
    align-items: flex-start;
  }

  .btn {
    width: 100%;
    justify-content: center;
  }
}