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

html {
  scroll-behavior: smooth;
}

:root {
  --color-primary: #0055A4;
  --color-primary-dark: #003D7A;
  --color-accent: #FF6600;
  --color-accent-dark: #E65C00;
  --color-neutral-dark: #2C2C2C;
  --color-neutral-light: #F5F5F5;
  --color-white: #FFFFFF;
  --font-sans: 'Inter', 'Noto Sans SC', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-mono: 'JetBrains Mono', 'SF Mono', 'Fira Code', monospace;
  --header-height: 70px;
  --content-max-width: 1200px;
  --focus-ring: 0 0 0 3px rgba(0, 85, 164, 0.4);
}

body {
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.6;
  color: var(--color-neutral-dark);
  background-color: var(--color-neutral-light);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

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

a {
  color: var(--color-primary);
  text-decoration: underline;
  text-underline-offset: 0.2em;
  transition: color 0.2s ease;
}

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

a:focus-visible {
  outline: none;
  box-shadow: var(--focus-ring);
  border-radius: 2px;
}

ul, ol {
  list-style: none;
}

/* === Skip Link === */
.skip-link {
  position: absolute;
  top: -100%;
  left: 0;
  z-index: 10000;
  padding: 0.75rem 1.5rem;
  background-color: var(--color-primary);
  color: var(--color-white);
  font-family: var(--font-mono);
  font-size: 0.875rem;
  text-decoration: none;
  clip: rect(1px, 1px, 1px, 1px);
  white-space: nowrap;
}

.skip-link:focus {
  top: 0;
  clip: auto;
  white-space: normal;
  clip-path: none;
}

/* === Reading Progress === */
.reading-progress {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 4px;
  z-index: 10001;
  background-color: rgba(44, 44, 44, 0.1);
  pointer-events: none;
}

.reading-progress__bar {
  height: 100%;
  width: 0%;
  background: linear-gradient(90deg, var(--color-primary) 0%, var(--color-accent) 100%);
  transition: width 0.1s linear;
}

/* === Header === */
.ok-header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: var(--header-height);
  z-index: 1000;
  background-color: transparent;
  transition: background-color 0.3s ease, box-shadow 0.3s ease;
}

[data-header-scrolled] .ok-header {
  background-color: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  box-shadow: 0 2px 24px rgba(0, 0, 0, 0.08);
}

.ok-header__inner {
  max-width: var(--content-max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 2rem;
}

/* === Logo === */
.ok-header__logo {
  font-family: var(--font-sans);
  font-size: 1.75rem;
  font-weight: 700;
  font-style: italic;
  text-decoration: none;
  color: var(--color-neutral-dark);
  white-space: nowrap;
  flex-shrink: 0;
}

.ok-header__logo span {
  color: var(--color-accent);
}

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

/* === Navigation Toggle === */
.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 5px;
  width: 40px;
  height: 40px;
  background: none;
  border: 1px solid var(--color-neutral-dark);
  border-radius: 4px;
  cursor: pointer;
  transition: border-color 0.2s ease;
}

.nav-toggle:hover {
  border-color: var(--color-accent);
}

.nav-toggle__line {
  display: block;
  width: 22px;
  height: 2px;
  background-color: var(--color-neutral-dark);
  border-radius: 1px;
  transition: transform 0.3s ease, opacity 0.3s ease;
}

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

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

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

/* === Navigation === */
.ok-nav__list {
  display: flex;
  align-items: center;
  gap: 2rem;
}

.ok-nav__list a {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  text-decoration: none;
  color: var(--color-neutral-dark);
  padding: 0.5rem 0;
  position: relative;
  transition: color 0.2s ease;
  white-space: nowrap;
}

.ok-nav__list a::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background-color: var(--color-accent);
  transition: width 0.3s ease;
}

.ok-nav__list a:hover {
  color: var(--color-primary);
}

.ok-nav__list a:hover::after {
  width: 100%;
}

.ok-nav__list a[aria-current="page"] {
  color: var(--color-primary);
  font-weight: 600;
}

.ok-nav__list a[aria-current="page"]::after {
  width: 100%;
  background-color: var(--color-primary);
}

/* === Heading Styles (Used across site) === */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-sans);
  font-weight: 700;
  font-style: italic;
  line-height: 1.2;
  color: var(--color-neutral-dark);
}

h1 {
  font-size: clamp(2.5rem, 6vw, 4.5rem);
  letter-spacing: -0.02em;
}

h2 {
  font-size: clamp(2rem, 4vw, 3rem);
  letter-spacing: -0.01em;
}

/* === Main Content === */
#main-content {
  min-height: 80vh;
  padding-top: calc(var(--header-height) + 1rem);
}

/* === Container === */
.container {
  max-width: var(--content-max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* === Footer === */
.ok-footer {
  background: linear-gradient(135deg, var(--color-primary-dark) 0%, var(--color-primary) 100%);
  color: var(--color-white);
  padding: 3rem 0 0;
  margin-top: 4rem;
}

.ok-footer a {
  color: var(--color-white);
  text-decoration: underline;
  text-underline-offset: 0.2em;
  transition: color 0.2s ease;
}

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

.ok-footer__inner {
  max-width: var(--content-max-width);
  margin: 0 auto;
  padding: 0 1.5rem 2rem;
  display: grid;
  grid-template-columns: 2fr 1fr 1.5fr;
  gap: 2.5rem;
  border-bottom: 1px solid rgba(255, 255, 255, 0.2);
}

.ok-footer__logo {
  font-family: var(--font-sans);
  font-size: 1.5rem;
  font-weight: 700;
  font-style: italic;
  text-decoration: none;
  display: inline-block;
  margin-bottom: 0.75rem;
}

.ok-footer__logo span {
  color: var(--color-accent);
}

.ok-footer__trust {
  font-size: 0.875rem;
  line-height: 1.6;
  opacity: 0.8;
  margin-top: 0.5rem;
}

.ok-footer__heading {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--color-white);
  margin-bottom: 1rem;
  border-bottom: 1px solid rgba(255, 255, 255, 0.3);
  padding-bottom: 0.5rem;
}

.ok-footer__list {
  display: flex;
  flex-direction: column;
  gap: 0.6rem;
}

.ok-footer__list a {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  text-decoration: none;
  transition: opacity 0.2s ease;
}

.ok-footer__list a:hover {
  opacity: 1;
  text-decoration: underline;
}

.ok-footer__list li {
  font-family: var(--font-sans);
  font-size: 0.875rem;
  line-height: 1.6;
  opacity: 0.9;
}

.ok-footer__bottom {
  max-width: var(--content-max-width);
  margin: 0 auto;
  padding: 1.5rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  flex-wrap: wrap;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  opacity: 0.7;
}

.ok-footer__bottom p {
  margin: 0;
}

/* === Responsive === */
@media (max-width: 768px) {
  .nav-toggle {
    display: flex;
  }

  .ok-nav {
    position: absolute;
    top: var(--header-height);
    left: 0;
    width: 100%;
    background-color: var(--color-white);
    border-top: 1px solid var(--color-neutral-light);
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    padding: 1rem 1.5rem;
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    transition: opacity 0.3s ease, transform 0.3s ease, visibility 0.3s ease;
  }

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

  .ok-nav__list {
    flex-direction: column;
    align-items: stretch;
    gap: 0.5rem;
  }

  .ok-nav__list a {
    display: block;
    padding: 0.75rem 0;
    border-bottom: 1px solid var(--color-neutral-light);
    text-transform: none;
    letter-spacing: 0;
  }

  .ok-nav__list a::after {
    display: none;
  }

  .ok-footer__inner {
    grid-template-columns: 1fr;
    gap: 2rem;
  }

  .ok-footer__bottom {
    flex-direction: column;
    text-align: center;
  }
}

@media (max-width: 480px) {
  .ok-header__logo {
    font-size: 1.4rem;
  }

  .container, .ok-header__inner, .ok-footer__inner, .ok-footer__bottom {
    padding-left: 1rem;
    padding-right: 1rem;
  }
}

/* === Reduced Motion === */
@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;
  }

  .reading-progress__bar {
    transition: none;
  }

  .ok-header {
    transition: none;
  }

  .ok-nav {
    transition: none;
  }

  .nav-toggle__line {
    transition: none;
  }
}