:root {
  --mui-primary: #1e88e5;
  --mui-primary-variant: #1565c0;
  --mui-surface: #ffffff;
  --mui-background: #f5f7fb;
  --mui-text-primary: #1f2933;
  --mui-text-secondary: #556071;
  --mui-border: #e0e7ef;
  --mui-radius: 16px;
  font-size: 16px;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: "Inter", "Helvetica Neue", Arial, sans-serif;
  background: var(--mui-background);
  color: var(--mui-text-primary);
  line-height: 1.6;
  min-height: 100vh;
}

a {
  color: inherit;
  text-decoration: none;
}

a:hover,
a:focus {
  color: var(--mui-primary);
}

.app-bar {
  padding: 1rem clamp(1.5rem, 5vw, 4rem);
  display: flex;
  align-items: center;
  justify-content: space-between;
  position: sticky;
  top: 0;
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(10px);
  z-index: 10;
  border-bottom: 1px solid var(--mui-border);
  box-shadow: 0 4px 18px rgba(0, 0, 0, 0.04);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.75rem;
  font-weight: 700;
  font-size: 1.3rem;
  letter-spacing: 0.04em;
  color: var(--mui-text-primary);
}

.brand .material-icons-outlined {
  color: var(--mui-primary);
  background: #e8f2ff;
  border-radius: 50%;
  padding: 0.4rem;
  font-size: 1.8rem;
}

nav ul {
  list-style: none;
  display: flex;
  gap: 0.75rem;
  margin: 0;
  padding: 0;
  font-weight: 600;
}

nav li a {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.65rem 1rem;
  border-radius: 12px;
  color: var(--mui-text-secondary);
  transition: background 0.2s ease, color 0.2s ease, box-shadow 0.2s ease;
}

nav li a:hover {
  background: #e8f2ff;
  color: var(--mui-primary);
  box-shadow: inset 0 0 0 1px rgba(30, 136, 229, 0.3);
}

main {
  padding: 0 clamp(1.5rem, 5vw, 4rem) 4rem;
}

.hero {
  margin-top: 2rem;
  display: grid;
  gap: 2.5rem;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  align-items: center;
}

.hero h1 {
  font-size: clamp(2.4rem, 5vw, 3.6rem);
  margin-bottom: 1rem;
}

.hero p {
  color: var(--mui-text-secondary);
  max-width: 36rem;
  margin: 0;
}

.hero-card {
  background: var(--mui-surface);
  border-radius: var(--mui-radius);
  padding: 1.5rem;
  box-shadow: 0 10px 40px rgba(15, 23, 42, 0.08);
  border: 1px solid var(--mui-border);
  display: grid;
  gap: 1rem;
}

.chip-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 1rem;
}

.chip {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.45rem 0.85rem;
  border-radius: 999px;
  background: #e8f2ff;
  color: var(--mui-primary);
  font-weight: 600;
  font-size: 0.95rem;
}

.chip .material-icons-round {
  font-size: 1.1rem;
}

.cta-buttons {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  margin-top: 1.5rem;
}

.button {
  padding: 0.85rem 1.6rem;
  border-radius: 12px;
  font-weight: 700;
  border: 1px solid var(--mui-primary);
  background: var(--mui-primary);
  color: #fff;
  transition: transform 0.2s ease, box-shadow 0.2s ease, background 0.2s ease;
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
}

.button.secondary {
  background: var(--mui-surface);
  color: var(--mui-primary);
  border-color: var(--mui-border);
  box-shadow: inset 0 0 0 1px var(--mui-border);
}

.button:hover {
  transform: translateY(-2px);
  box-shadow: 0 10px 24px rgba(21, 101, 192, 0.25);
  background: var(--mui-primary-variant);
}

.button.secondary:hover {
  background: #e8f2ff;
  color: var(--mui-primary-variant);
  box-shadow: inset 0 0 0 1px rgba(21, 101, 192, 0.35);
}

.section {
  margin-top: clamp(3.5rem, 8vw, 5.5rem);
}

.section-header {
  display: flex;
  flex-direction: column;
  gap: 0.65rem;
}

.section-header h2 {
  font-size: clamp(1.8rem, 4vw, 2.6rem);
  margin: 0;
}

.section-header p {
  color: var(--mui-text-secondary);
  max-width: 46rem;
}

.card-grid {
  display: grid;
  gap: 1.5rem;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  margin-top: 2rem;
}

.card {
  background: var(--mui-surface);
  border-radius: var(--mui-radius);
  padding: 1.75rem;
  border: 1px solid var(--mui-border);
  display: flex;
  flex-direction: column;
  gap: 1rem;
  transition: transform 0.18s ease, box-shadow 0.18s ease;
  box-shadow: 0 12px 36px rgba(15, 23, 42, 0.06);
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: 0 16px 40px rgba(21, 101, 192, 0.12);
}

.card h3 {
  margin: 0;
  font-size: 1.3rem;
}

.card p {
  color: var(--mui-text-secondary);
  flex: 1;
}

.meta {
  color: var(--mui-text-secondary);
  font-size: 0.9rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  font-weight: 700;
}

.meta .material-icons-round {
  font-size: 1.1rem;
  color: var(--mui-primary);
}

.image-placeholder {
  width: 100%;
  padding-top: 60%;
  background: linear-gradient(135deg, #e8f2ff, #f7fbff);
  border-radius: var(--mui-radius);
  position: relative;
  border: 1px dashed rgba(30, 136, 229, 0.25);
}

.image-placeholder::after {
  content: attr(data-image);
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  font-size: 0.9rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--mui-text-secondary);
}

.info-list {
  display: grid;
  gap: 0.75rem;
  margin-top: 1.25rem;
  padding: 0;
  list-style: none;
}

.info-item {
  display: flex;
  gap: 0.6rem;
  align-items: flex-start;
  color: var(--mui-text-secondary);
}

.info-item .material-icons-round {
  color: var(--mui-primary);
  background: #e8f2ff;
  border-radius: 8px;
  padding: 0.35rem;
}

footer {
  margin-top: clamp(3rem, 7vw, 5rem);
  padding: 2rem clamp(1.5rem, 5vw, 4rem) 3rem;
  border-top: 1px solid var(--mui-border);
  color: var(--mui-text-secondary);
  font-size: 0.95rem;
  background: var(--mui-surface);
  box-shadow: 0 -6px 24px rgba(15, 23, 42, 0.04);
}

footer nav ul {
  justify-content: center;
}

footer nav a {
  color: var(--mui-text-secondary);
  font-weight: 600;
}

.article {
  max-width: 860px;
  margin: 0 auto;
  background: var(--mui-surface);
  padding: 1.5rem 1.5rem 2.5rem;
  border-radius: var(--mui-radius);
  border: 1px solid var(--mui-border);
  box-shadow: 0 10px 30px rgba(15, 23, 42, 0.06);
}

.article header {
  position: static;
  padding: 0 0 1.5rem;
  margin-bottom: 1rem;
  border-bottom: 1px solid var(--mui-border);
  background: none;
  backdrop-filter: none;
}

.article header h1 {
  margin: 0 0 0.75rem;
  font-size: clamp(2.1rem, 4vw, 2.9rem);
}

.article header p {
  color: var(--mui-text-secondary);
  margin: 0;
}

.article-content {
  display: grid;
  gap: 1.5rem;
}

.article-content p {
  color: var(--mui-text-primary);
  font-size: 1.03rem;
}

.article-content blockquote {
  border-left: 4px solid var(--mui-primary);
  padding-left: 1.25rem;
  color: var(--mui-text-primary);
  font-style: italic;
  background: #f7fbff;
  border-radius: 0 12px 12px 0;
}

.article-meta {
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-size: 0.85rem;
  color: var(--mui-text-secondary);
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  font-weight: 700;
}

.article-meta .material-icons-round {
  font-size: 1rem;
  color: var(--mui-primary);
}

.back-link {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  font-weight: 700;
  color: var(--mui-primary);
  margin-bottom: 1rem;
}

.back-link .material-icons-round {
  font-size: 1.2rem;
}

@media (max-width: 900px) {
  nav ul {
    flex-wrap: wrap;
    justify-content: center;
  }

  main {
    padding: 0 1.25rem 3rem;
  }
}

@media (max-width: 720px) {
  .app-bar {
    flex-direction: column;
    gap: 1rem;
  }

  .hero {
    text-align: center;
  }

  .hero p {
    margin: 0 auto;
  }

  .cta-buttons {
    justify-content: center;
  }
}