/* =========================================
   DHUX - Digital Health User Experience
   Global Stylesheet
   ========================================= */

/* -----------------------------------------
   CSS Custom Properties (Design Tokens)
   ----------------------------------------- */
:root {
  /* Color Palette - Medical/Tech Aesthetic */
  --color-primary: #0F766E;
  --color-primary-dark: #0D5C56;
  --color-primary-light: #14B8A6;
  --color-secondary: #475569;
  --color-secondary-dark: #334155;
  --color-secondary-light: #64748B;
  --color-background: #FFFFFF;
  --color-background-alt: #F8FAFC;
  --color-accent: #E0F2FE;
  --color-accent-dark: #BAE6FD;
  --color-text: #1E293B;
  --color-text-muted: #64748B;
  --color-border: #E2E8F0;
  --color-success: #059669;
  --color-warning: #D97706;
  --color-error: #DC2626;

  /* Typography */
  --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Inter', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
  --font-size-xs: 0.75rem;
  --font-size-sm: 0.875rem;
  --font-size-base: 1rem;
  --font-size-lg: 1.125rem;
  --font-size-xl: 1.25rem;
  --font-size-2xl: 1.5rem;
  --font-size-3xl: 1.875rem;
  --font-size-4xl: 2.25rem;
  --font-size-5xl: 3rem;

  /* Font Weights */
  --font-weight-normal: 400;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;
  --font-weight-bold: 700;

  /* Spacing */
  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 1.5rem;
  --spacing-xl: 2rem;
  --spacing-2xl: 3rem;
  --spacing-3xl: 4rem;
  --spacing-4xl: 6rem;

  /* Layout */
  --max-width: 1200px;
  --max-width-content: 800px;
  --header-height: 70px;

  /* Border Radius */
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-xl: 16px;
  --radius-full: 9999px;

  /* Shadows */
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -2px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -4px rgba(0, 0, 0, 0.1);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 8px 10px -6px rgba(0, 0, 0, 0.1);

  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-base: 250ms ease;
  --transition-slow: 350ms ease;
}

/* -----------------------------------------
   CSS Reset & Base Styles
   ----------------------------------------- */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

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

body {
  font-family: var(--font-family);
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-normal);
  line-height: 1.6;
  color: var(--color-text);
  background-color: var(--color-background);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

img,
picture,
video,
canvas,
svg {
  display: block;
  max-width: 100%;
  height: auto;
}

input,
button,
textarea,
select {
  font: inherit;
}

a {
  color: var(--color-primary);
  text-decoration: none;
  transition: color var(--transition-fast);
}

a:hover {
  color: var(--color-primary-dark);
}

a:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
  border-radius: var(--radius-sm);
}

ul,
ol {
  list-style: none;
}

h1,
h2,
h3,
h4,
h5,
h6 {
  font-weight: var(--font-weight-bold);
  line-height: 1.2;
  color: var(--color-text);
}

h1 {
  font-size: var(--font-size-4xl);
}

h2 {
  font-size: var(--font-size-3xl);
}

h3 {
  font-size: var(--font-size-2xl);
}

h4 {
  font-size: var(--font-size-xl);
}

p {
  margin-bottom: var(--spacing-md);
}

/* -----------------------------------------
   Utility Classes
   ----------------------------------------- */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--spacing-lg);
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.text-center {
  text-align: center;
}

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

/* -----------------------------------------
   Header & Navigation
   ----------------------------------------- */
.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--header-height);
  background-color: var(--color-background);
  border-bottom: 1px solid var(--color-border);
  z-index: 1000;
}

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

.logo {
  font-size: var(--font-size-2xl);
  font-weight: var(--font-weight-bold);
  color: var(--color-primary);
  letter-spacing: -0.5px;
}

.logo:hover {
  color: var(--color-primary-dark);
}

.nav {
  display: flex;
  align-items: center;
}

.nav__list {
  display: flex;
  gap: var(--spacing-xl);
}

.nav__link {
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-medium);
  color: var(--color-secondary);
  padding: var(--spacing-sm) 0;
  position: relative;
}

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

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

.nav__link:hover::after,
.nav__link--active::after {
  width: 100%;
}

/* Mobile Menu Toggle */
.menu-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  width: 44px;
  height: 44px;
  padding: var(--spacing-sm);
  background: none;
  border: none;
  cursor: pointer;
  gap: 5px;
}

.menu-toggle__bar {
  display: block;
  width: 24px;
  height: 2px;
  background-color: var(--color-secondary);
  transition: transform var(--transition-base), opacity var(--transition-base);
}

.menu-toggle[aria-expanded="true"] .menu-toggle__bar:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.menu-toggle[aria-expanded="true"] .menu-toggle__bar:nth-child(2) {
  opacity: 0;
}

.menu-toggle[aria-expanded="true"] .menu-toggle__bar:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* -----------------------------------------
   Main Content
   ----------------------------------------- */
.main {
  margin-top: var(--header-height);
}

/* -----------------------------------------
   Hero Section
   ----------------------------------------- */
.hero {
  padding: var(--spacing-4xl) 0;
  background: linear-gradient(135deg, var(--color-background) 0%, var(--color-accent) 100%);
  text-align: center;
}

.hero__container {
  max-width: 900px;
  margin: 0 auto;
}

.hero__badge {
  display: inline-block;
  padding: var(--spacing-xs) var(--spacing-md);
  background-color: var(--color-primary);
  color: white;
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  border-radius: var(--radius-full);
  margin-bottom: var(--spacing-lg);
}

.hero__title {
  font-size: var(--font-size-5xl);
  font-weight: var(--font-weight-bold);
  color: var(--color-text);
  margin-bottom: var(--spacing-lg);
  line-height: 1.1;
}

.hero__title-highlight {
  color: var(--color-primary);
}

.hero__subtitle {
  font-size: var(--font-size-xl);
  color: var(--color-text-muted);
  max-width: 700px;
  margin: 0 auto var(--spacing-xl);
  line-height: 1.6;
}

.hero__cta {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-md) var(--spacing-xl);
  background-color: var(--color-primary);
  color: white;
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-semibold);
  border-radius: var(--radius-md);
  transition: background-color var(--transition-fast), transform var(--transition-fast);
}

.hero__cta:hover {
  background-color: var(--color-primary-dark);
  color: white;
  transform: translateY(-2px);
}

.hero__cta:focus-visible {
  outline: 2px solid var(--color-primary-dark);
  outline-offset: 2px;
}

/* -----------------------------------------
   Features Section
   ----------------------------------------- */
.features {
  padding: var(--spacing-4xl) 0;
  background-color: var(--color-background);
}

.section__header {
  text-align: center;
  margin-bottom: var(--spacing-3xl);
}

.section__title {
  font-size: var(--font-size-3xl);
  margin-bottom: var(--spacing-md);
}

.section__subtitle {
  font-size: var(--font-size-lg);
  color: var(--color-text-muted);
  max-width: 600px;
  margin: 0 auto;
}

.features__grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--spacing-xl);
}

.feature-card {
  padding: var(--spacing-xl);
  background-color: var(--color-background);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  transition: box-shadow var(--transition-base), transform var(--transition-base);
}

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

.feature-card__icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 56px;
  height: 56px;
  background-color: var(--color-accent);
  border-radius: var(--radius-md);
  margin-bottom: var(--spacing-lg);
  color: var(--color-primary);
  font-size: var(--font-size-2xl);
}

.feature-card__title {
  font-size: var(--font-size-xl);
  margin-bottom: var(--spacing-sm);
}

.feature-card__description {
  color: var(--color-text-muted);
  margin-bottom: 0;
}

/* -----------------------------------------
   Articles Section
   ----------------------------------------- */
.articles {
  padding: var(--spacing-4xl) 0;
  background-color: var(--color-background-alt);
}

.articles__grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--spacing-xl);
}

.article-card {
  background-color: var(--color-background);
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
  transition: box-shadow var(--transition-base), transform var(--transition-base);
  display: flex;
  flex-direction: column;
}

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

.article-card__image {
  width: 100%;
  height: 200px;
  background-color: var(--color-accent);
  overflow: hidden;
  position: relative;
  flex-shrink: 0;
}

/* Fallback for icons (articles without images) */
.article-card__image:not(:has(img)) {
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: var(--font-size-4xl);
  color: var(--color-primary);
}

.article-card__image img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
  transition: transform var(--transition-base);
}

.article-card:hover .article-card__image img {
  transform: scale(1.05);
}

.article-card__content {
  padding: var(--spacing-lg);
  position: relative;
  background-color: var(--color-background);
}

.article-card__category {
  display: inline-block;
  font-size: var(--font-size-xs);
  font-weight: var(--font-weight-semibold);
  text-transform: uppercase;
  letter-spacing: 0.5px;
  color: var(--color-primary);
  margin-bottom: var(--spacing-sm);
}

.article-card__title {
  font-size: var(--font-size-lg);
  margin-bottom: var(--spacing-sm);
  line-height: 1.4;
}

.article-card__title a {
  color: var(--color-text);
}

.article-card__title a:hover {
  color: var(--color-primary);
}

.article-card__excerpt {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  margin-bottom: var(--spacing-md);
  line-height: 1.6;
}

.article-card__meta {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
}

.article-card__link {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-xs);
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-semibold);
  color: var(--color-primary);
}

.article-card__link:hover {
  gap: var(--spacing-sm);
}

/* -----------------------------------------
   Footer
   ----------------------------------------- */
.footer {
  padding: var(--spacing-3xl) 0 var(--spacing-xl);
  background-color: var(--color-secondary-dark);
  color: white;
}

.footer__container {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: var(--spacing-2xl);
}

.footer__brand {
  max-width: 300px;
}

.footer__logo {
  font-size: var(--font-size-2xl);
  font-weight: var(--font-weight-bold);
  color: white;
  margin-bottom: var(--spacing-md);
}

.footer__description {
  color: rgba(255, 255, 255, 0.7);
  font-size: var(--font-size-sm);
  line-height: 1.7;
}

.footer__title {
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-semibold);
  margin-bottom: var(--spacing-md);
  color: white;
}

.footer__list {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
}

.footer__link {
  color: rgba(255, 255, 255, 0.7);
  font-size: var(--font-size-sm);
  transition: color var(--transition-fast);
}

.footer__link:hover {
  color: white;
}

.footer__bottom {
  margin-top: var(--spacing-2xl);
  padding-top: var(--spacing-xl);
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.footer__copyright {
  font-size: var(--font-size-sm);
  color: rgba(255, 255, 255, 0.7);
}

.footer__keywords {
  font-size: var(--font-size-xs);
  color: rgba(255, 255, 255, 0.5);
}

/* -----------------------------------------
   Blog Post Styles
   ----------------------------------------- */
.blog-post {
  max-width: var(--max-width-content);
  margin: 0 auto;
  padding: var(--spacing-3xl) var(--spacing-lg);
}

.blog-post__header {
  margin-bottom: var(--spacing-2xl);
  text-align: center;
}

.blog-post__category {
  display: inline-block;
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-semibold);
  text-transform: uppercase;
  letter-spacing: 0.5px;
  color: var(--color-primary);
  margin-bottom: var(--spacing-md);
}

.blog-post__title {
  font-size: var(--font-size-4xl);
  margin-bottom: var(--spacing-md);
  line-height: 1.2;
}

.blog-post__meta {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: var(--spacing-lg);
  color: var(--color-text-muted);
  font-size: var(--font-size-sm);
}

.blog-post__featured-image {
  margin: 0 0 var(--spacing-2xl);
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-md);
}

.blog-post__featured-image img {
  width: 100%;
  height: auto;
  display: block;
}

.blog-post__content {
  font-size: var(--font-size-lg);
  line-height: 1.8;
}

.blog-post__content h2 {
  margin-top: var(--spacing-2xl);
  margin-bottom: var(--spacing-md);
  padding-top: var(--spacing-md);
  border-top: 1px solid var(--color-border);
}

.blog-post__content h3 {
  margin-top: var(--spacing-xl);
  margin-bottom: var(--spacing-sm);
}

.blog-post__content p {
  margin-bottom: var(--spacing-lg);
}

.blog-post__content ul,
.blog-post__content ol {
  margin-bottom: var(--spacing-lg);
  padding-left: var(--spacing-xl);
}

.blog-post__content ul {
  list-style: disc;
}

.blog-post__content ol {
  list-style: decimal;
}

.blog-post__content li {
  margin-bottom: var(--spacing-sm);
}

.blog-post__content strong {
  font-weight: var(--font-weight-semibold);
}

.blog-post__content a {
  text-decoration: underline;
  text-underline-offset: 2px;
}

/* Code Blocks */
.blog-post__content code {
  font-family: 'SF Mono', 'Fira Code', 'Consolas', monospace;
  font-size: 0.9em;
  padding: 0.2em 0.4em;
  background-color: var(--color-background-alt);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  color: var(--color-primary-dark);
}

.blog-post__content pre {
  margin: var(--spacing-lg) 0;
  padding: var(--spacing-lg);
  background-color: var(--color-secondary-dark);
  border-radius: var(--radius-md);
  overflow-x: auto;
}

.blog-post__content pre code {
  display: block;
  padding: 0;
  background: none;
  border: none;
  color: #E2E8F0;
  font-size: var(--font-size-sm);
  line-height: 1.6;
}

/* Blockquote */
.blog-post__content blockquote {
  margin: var(--spacing-lg) 0;
  padding: var(--spacing-md) var(--spacing-lg);
  border-left: 4px solid var(--color-primary);
  background-color: var(--color-accent);
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
}

.blog-post__content blockquote p {
  margin-bottom: 0;
  font-style: italic;
  color: var(--color-secondary);
}

/* Info Box */
.info-box {
  margin: var(--spacing-lg) 0;
  padding: var(--spacing-lg);
  background-color: var(--color-accent);
  border: 1px solid var(--color-accent-dark);
  border-radius: var(--radius-md);
}

.info-box--warning {
  background-color: #FEF3C7;
  border-color: #FCD34D;
}

.info-box--success {
  background-color: #D1FAE5;
  border-color: #6EE7B7;
}

.info-box__title {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-semibold);
  margin-bottom: var(--spacing-sm);
}

.info-box__content {
  font-size: var(--font-size-sm);
}

.info-box__content p:last-child {
  margin-bottom: 0;
}

/* Back Link */
.blog-post__back {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing-xl);
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  color: var(--color-secondary);
}

.blog-post__back:hover {
  color: var(--color-primary);
}

/* -----------------------------------------
   Responsive Design
   ----------------------------------------- */
@media (max-width: 1024px) {
  .features__grid,
  .articles__grid {
    grid-template-columns: repeat(2, 1fr);
  }

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

@media (max-width: 768px) {
  :root {
    --font-size-5xl: 2.25rem;
    --font-size-4xl: 1.875rem;
    --font-size-3xl: 1.5rem;
  }

  .menu-toggle {
    display: flex;
  }

  .nav {
    position: fixed;
    top: var(--header-height);
    left: 0;
    right: 0;
    background-color: var(--color-background);
    border-bottom: 1px solid var(--color-border);
    padding: var(--spacing-lg);
    transform: translateY(-100%);
    opacity: 0;
    visibility: hidden;
    transition: transform var(--transition-base), opacity var(--transition-base), visibility var(--transition-base);
  }

  .nav--open {
    transform: translateY(0);
    opacity: 1;
    visibility: visible;
  }

  .nav__list {
    flex-direction: column;
    gap: var(--spacing-md);
  }

  .nav__link {
    display: block;
    padding: var(--spacing-sm) 0;
  }

  .features__grid,
  .articles__grid {
    grid-template-columns: 1fr;
  }

  .footer__container {
    grid-template-columns: 1fr;
    gap: var(--spacing-xl);
  }

  .footer__bottom {
    flex-direction: column;
    gap: var(--spacing-md);
    text-align: center;
  }

  .hero {
    padding: var(--spacing-2xl) 0;
  }

  .blog-post__meta {
    flex-direction: column;
    gap: var(--spacing-sm);
  }
}

@media (max-width: 480px) {
  .container {
    padding: 0 var(--spacing-md);
  }

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

  .article-card__image {
    height: 150px;
  }
}

/* -----------------------------------------
   Accessibility Enhancements
   ----------------------------------------- */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}

/* High Contrast Mode Support */
@media (prefers-contrast: high) {
  :root {
    --color-border: #000000;
    --color-text-muted: #1E293B;
  }

  .feature-card,
  .article-card {
    border-width: 2px;
  }
}

/* Focus Styles */
:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

/* Skip Link */
.skip-link {
  position: absolute;
  top: -100%;
  left: 50%;
  transform: translateX(-50%);
  padding: var(--spacing-md) var(--spacing-lg);
  background-color: var(--color-primary);
  color: white;
  font-weight: var(--font-weight-semibold);
  border-radius: var(--radius-md);
  z-index: 9999;
  transition: top var(--transition-fast);
}

.skip-link:focus {
  top: var(--spacing-md);
}