/* Refactored CSS using modern selectors + nesting.
   Key decisions:
   - :where() for base styles so they stay easy to override (0 specificity)
   - :is() to reduce repeated selector blocks without changing visuals
   - :has() to replace class-based “card with image” logic using pure CSS
*/

/* Base styles (low specificity on purpose) */
:where(*) {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

:where(body) {
  font-family: system-ui, -apple-system, sans-serif;
  line-height: 1.6;
  color: #333;
}

:where(a) {
  text-decoration: none;
  color: inherit;
}

:where(button) {
  font-family: inherit;
  cursor: pointer;
}

/* Header + Navigation */
.site-header {
  background: white;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
  position: sticky;
  top: 0;
  z-index: 100;

  /* Using :where(#navigation) prevents the ID from raising specificity */
  :where(#navigation) {
    max-width: 1200px;
    margin: 0 auto;
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;

    & .logo {
      font-size: 1.5rem;
      font-weight: 700;
      color: #667eea;
    }

    & .nav-list {
      list-style: none;
      display: flex;
      gap: 2rem;

      & .nav-item {
        & .nav-link {
          color: #666;
          font-weight: 500;
          transition: color 0.3s;

          &:hover {
            color: #667eea;
          }

          &:focus {
            outline: 2px solid #667eea;
            outline-offset: 4px;
          }

          &.active {
            color: #667eea;
            font-weight: 600;
          }
        }
      }
    }
  }
}

/* Hero */
.hero {
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  padding: 6rem 2rem;
  text-align: center;

  & .hero-content {
    max-width: 800px;
    margin: 0 auto;

    & .hero-title {
      font-size: 3rem;
      color: white;
      margin-bottom: 1rem;
    }

    & .hero-subtitle {
      font-size: 1.25rem;
      color: rgba(255, 255, 255, 0.9);
      margin-bottom: 2rem;
    }
  }
}

/* Buttons */
.btn {
  padding: 0.75rem 2rem;
  border: none;
  border-radius: 0.5rem;
  font-size: 1rem;
  font-weight: 600;
  transition: transform 0.2s, box-shadow 0.2s;

  &:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
  }

  &:focus {
    outline: 2px solid #667eea;
    outline-offset: 2px;
  }

  /* :is() groups variant selectors without repeating properties */
  &:is(.btn-primary) {
    background: white;
    color: #667eea;

    &:hover {
      background: #f8f9fa;
    }
  }

  &:is(.btn-secondary) {
    background: transparent;
    color: white;
    border: 2px solid white;

    &:hover {
      background: rgba(255, 255, 255, 0.1);
    }
  }
}

/* Shared layout container */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 4rem 2rem;
}

/* Section title pattern:
   :is() reduces repetition across sections that share the same title style */
:is(.features, .testimonials) {
  & .section-title {
    font-size: 2.5rem;
    text-align: center;
    margin-bottom: 3rem;
    color: #333;
  }
}

/* These are overrides that existed in the old CSS (kept the same) */
.hero {
  & .hero-content {
    & .section-title {
      color: white;
    }
  }
}

.testimonials {
  & .section-title {
    color: #667eea;
  }
}

.cta {
  & .cta-title {
    font-size: 2.5rem;
    text-align: center;
    margin-bottom: 1rem;
    color: white;
  }
}

/* Features */
.features {
  background: #f8f9fa;

  & .feature-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;

    & .card {
      background: white;
      border-radius: 0.5rem;
      overflow: hidden;
      box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
      transition: transform 0.3s, box-shadow 0.3s;

      &:hover {
        transform: translateY(-4px);
        box-shadow: 0 8px 24px rgba(0, 0, 0, 0.15);
      }

      /* :has() replaces old class-based “featured layout” logic.
         In this HTML, every feature card contains an <img>, so this matches the same set. */
      &:has(img) {
        display: grid;
        grid-template-rows: 200px 1fr;
      }

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

      & .card-content {
        padding: 1.5rem;

        & .card-title {
          font-size: 1.5rem;
          margin-bottom: 0.5rem;
          color: #333;
        }

        & .card-text {
          color: #666;
          margin-bottom: 1rem;
          line-height: 1.6;
        }

        & .card-link {
          color: #667eea;
          font-weight: 600;
          display: inline-block;

          &:hover {
            text-decoration: underline;
          }
        }
      }
    }
  }
}

/* Testimonials */
.testimonials {
  background: white;

  & .testimonial-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;

    & .testimonial {
      background: #f8f9fa;
      padding: 2rem;
      border-radius: 0.5rem;
      border-left: 4px solid #667eea;

      & .testimonial-text {
        font-size: 1.125rem;
        font-style: italic;
        color: #555;
        margin-bottom: 1.5rem;
      }

      & .testimonial-author {
        display: block;
        font-weight: 600;
        color: #333;
        margin-bottom: 0.25rem;
        font-style: normal;
      }

      & .testimonial-role {
        display: block;
        color: #888;
        font-size: 0.9rem;
      }
    }
  }
}

/* Stats */
.stats {
  background: #667eea;
  padding: 4rem 2rem;

  & .stats-grid {
    max-width: 1200px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 3rem;

    & .stat-item {
      text-align: center;

      & .stat-number {
        display: block;
        font-size: 3rem;
        font-weight: 700;
        color: white;
        margin-bottom: 0.5rem;
      }

      & .stat-label {
        display: block;
        color: rgba(255, 255, 255, 0.9);
        font-size: 1.125rem;
      }

      /* :is() avoids repeating both stat selectors for the highlight variant */
      &.highlight {
        & :is(.stat-number, .stat-label) {
          color: #ffd700;
        }
      }
    }
  }
}

/* CTA */
.cta {
  background: linear-gradient(135deg, #764ba2 0%, #667eea 100%);
  padding: 6rem 2rem;
  text-align: center;

  & .cta-text {
    font-size: 1.25rem;
    color: rgba(255, 255, 255, 0.9);
    margin-bottom: 2rem;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
  }

  & .cta-buttons {
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
  }
}

/* Footer */
.site-footer {
  background: #1a1a1a;
  color: white;
  padding: 3rem 2rem 1rem;

  & .container {
    padding: 0 2rem;
  }

  & .footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 2rem;
    margin-bottom: 2rem;

    & .footer-section {
      & .footer-title {
        font-size: 1.25rem;
        margin-bottom: 1rem;
        color: white;
      }

      & .footer-links {
        list-style: none;

        & .footer-link-item {
          margin-bottom: 0.5rem;

          & .footer-link {
            color: #999;
            transition: color 0.3s;

            &:hover {
              color: #667eea;
            }
          }
        }
      }
    }
  }

  & .footer-bottom {
    border-top: 1px solid #333;
    padding-top: 2rem;
    text-align: center;

    & .copyright {
      color: #666;
    }
  }
}

/* Responsive adjustments (same breakpoint + values as old CSS) */
@media (max-width: 768px) {
  .hero {
    & .hero-content {
      & .hero-title {
        font-size: 2rem;
      }
    }
  }

  .section-title {
    font-size: 2rem;
  }

  .cta {
    & .cta-title {
      font-size: 2rem;
    }
  }

  :where(#navigation) {
    flex-direction: column;
    gap: 1rem;

    & .nav-list {
      gap: 1rem;
    }
  }
}