/* ==========================================================================
   Google Fonts Import
   ========================================================================== */

@import url('https://fonts.googleapis.com/css2?family=Lato:wght@300;400;700;900&display=swap');

/* ==========================================================================
   Design Tokens (CSS Custom Properties)
   ========================================================================== */

:root {
  /* Colors */
  --color-primary: #1772d0;
  --color-primary-hover: #f09228;
  --color-text: #1a1a2e;
  --color-text-muted: #555;
  --color-bg: #ffffff;
  --color-bg-alt: #f8f9fa;
  --color-border: #e0e0e0;
  --color-accent: #1772d0;

  /* Typography */
  --font-family: 'Lato', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-size-base: 16px;
  --font-size-sm: 14px;
  --font-size-lg: 18px;
  --font-size-h1: 36px;
  --font-size-h2: 28px;
  --font-size-h3: 22px;
  --line-height: 1.6;

  /* Spacing (8px base unit) */
  --space-xs: 4px;
  --space-sm: 8px;
  --space-md: 16px;
  --space-lg: 32px;
  --space-xl: 48px;
  --space-2xl: 64px;
  --space-section: 80px;

  /* Layout */
  --max-width: 900px;
  --nav-height: 60px;
  --border-radius: 6px;

  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-normal: 250ms ease;
}

/* ==========================================================================
   CSS Reset
   ========================================================================== */

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

* {
  margin: 0;
  padding: 0;
}

/* ==========================================================================
   Scroll Offset for Fixed Navigation
   ========================================================================== */

section[id] {
  scroll-margin-top: var(--nav-height);
}

/* ==========================================================================
   Base Typography
   ========================================================================== */

html {
  scroll-behavior: smooth;
  overflow-x: hidden;
}

body {
  font-family: var(--font-family);
  font-size: var(--font-size-base);
  line-height: var(--line-height);
  color: var(--color-text);
  background-color: var(--color-bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
  min-width: 320px;
}

h1,
h2,
h3,
h4,
h5,
h6 {
  line-height: 1.2;
  font-weight: 700;
}

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

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

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

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

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

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

/* ==========================================================================
   Global Focus Indicators (Requirement 11.3)
   ========================================================================== */

a:focus-visible,
button:focus-visible,
[role="button"]:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
  border-radius: 2px;
}

ul,
ol {
  list-style: none;
}

/* ==========================================================================
   Navigation Bar
   ========================================================================== */

.site-nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  height: var(--nav-height);
  background-color: var(--color-bg);
  border-bottom: 1px solid var(--color-border);
}

.site-nav__container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space-md);
  height: 100%;
}

.site-nav__brand {
  font-size: var(--font-size-lg);
  font-weight: 700;
  color: var(--color-text);
  text-decoration: none;
  min-width: 44px;
  min-height: 44px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

.site-nav__brand:hover,
.site-nav__brand:focus {
  color: var(--color-primary);
}

/* Hamburger toggle button */
.site-nav__toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--space-sm);
  border-radius: var(--border-radius);
  transition: background-color var(--transition-fast);
}

.site-nav__toggle:hover,
.site-nav__toggle:focus-visible {
  background-color: var(--color-bg-alt);
}

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

/* Hamburger icon (three lines) */
.site-nav__hamburger {
  display: block;
  width: 22px;
  height: 2px;
  background-color: var(--color-text);
  position: relative;
  transition: background-color var(--transition-fast);
}

.site-nav__hamburger::before,
.site-nav__hamburger::after {
  content: '';
  position: absolute;
  left: 0;
  width: 100%;
  height: 2px;
  background-color: var(--color-text);
  transition: transform var(--transition-normal);
}

.site-nav__hamburger::before {
  top: -7px;
}

.site-nav__hamburger::after {
  top: 7px;
}

/* Nav list (mobile: visible by default for no-JS accessibility) */
.site-nav__list {
  display: flex;
  position: absolute;
  top: var(--nav-height);
  left: 0;
  right: 0;
  background-color: var(--color-bg);
  border-bottom: 1px solid var(--color-border);
  padding: var(--space-sm) 0;
  list-style: none;
  flex-direction: column;
}

/* When JS is enabled, hide nav list by default on mobile */
.js-enabled .site-nav__list {
  display: none;
}

/* Show nav list when toggle is activated (JS adds this class) */
.js-enabled .site-nav__list--open {
  display: flex;
}

/* Nav links */
.site-nav__link {
  display: flex;
  align-items: center;
  padding: var(--space-sm) var(--space-md);
  min-height: 44px;
  color: var(--color-text);
  text-decoration: none;
  font-size: var(--font-size-base);
  font-weight: 400;
  transition: color var(--transition-fast), background-color var(--transition-fast);
}

.site-nav__link:hover,
.site-nav__link:focus {
  color: var(--color-primary);
  background-color: var(--color-bg-alt);
}

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

/* Active link highlighting */
.site-nav__link--active {
  color: var(--color-primary);
  font-weight: 700;
}

/* Offset main content below fixed nav */
body {
  padding-top: var(--nav-height);
}

/* Desktop navigation (≥ 768px) */
@media (min-width: 768px) {
  .site-nav__toggle {
    display: none;
  }

  .site-nav__list,
  .js-enabled .site-nav__list {
    display: flex;
    position: static;
    flex-direction: row;
    border-bottom: none;
    padding: 0;
    gap: var(--space-xs);
  }

  .site-nav__link {
    padding: var(--space-sm) var(--space-sm);
    border-radius: var(--border-radius);
    font-size: var(--font-size-sm);
  }

  .site-nav__link:hover,
  .site-nav__link:focus {
    background-color: var(--color-bg-alt);
  }
}

/* ==========================================================================
   Layout Utilities and Container Styles
   ========================================================================== */

/* Main content container */
.site-main {
  width: 100%;
  max-width: var(--max-width);
  margin-left: auto;
  margin-right: auto;
  padding-left: var(--space-md);
  padding-right: var(--space-md);
}

/* Section spacing utility */
.site-main > section {
  padding-top: var(--space-section);
  padding-bottom: var(--space-section);
}

/* Ensure all elements respect container boundaries */
.site-main * {
  max-width: 100%;
}

/* Images scale proportionally within their containers */
.site-main img {
  height: auto;
  max-width: 100%;
}

/* ==========================================================================
   Responsive Layout - Mobile First (< 768px)
   ========================================================================== */

/* Base: single-column layout for all sections */
.hero__container,
.blog__list,
.interests__grid,
.links__categories,
.reading-list__entries {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-lg);
}

/* Touch targets: minimum 44x44px for interactive elements on mobile */
.site-nav__link,
.site-nav__toggle,
.hero__resume-btn,
.hero__social a {
  min-width: 44px;
  min-height: 44px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

/* ==========================================================================
   Hero Section
   ========================================================================== */

.hero {
  padding-top: var(--space-xl);
  padding-bottom: var(--space-xl);
}

.hero__name {
  margin-bottom: var(--space-sm);
}

.hero__title {
  font-size: var(--font-size-lg);
  color: var(--color-text-muted);
  margin-bottom: var(--space-md);
}

.hero__summary {
  font-size: var(--font-size-base);
  line-height: var(--line-height);
  color: var(--color-text);
  max-width: 600px;
}

/* Hero Actions (Resume Button) */
.hero__actions {
  margin-top: var(--space-lg);
}

.hero__resume-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 44px;
  min-height: 44px;
  padding: var(--space-sm) var(--space-lg);
  background-color: var(--color-primary);
  color: #ffffff;
  font-size: var(--font-size-base);
  font-weight: 700;
  text-decoration: none;
  border-radius: var(--border-radius);
  transition: background-color var(--transition-normal), transform var(--transition-fast);
}

.hero__resume-btn:hover,
.hero__resume-btn:focus {
  background-color: var(--color-primary-hover);
  color: #ffffff;
  transform: translateY(-1px);
}

.hero__resume-btn:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 3px;
}

/* Hero Social Links */
.hero__social {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-md);
  margin-top: var(--space-md);
  list-style: none;
  padding: 0;
}

.hero__social a {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 44px;
  min-height: 44px;
  padding: var(--space-sm) var(--space-sm);
  color: var(--color-text-muted);
  font-size: var(--font-size-base);
  font-weight: 400;
  text-decoration: none;
  border-radius: var(--border-radius);
  transition: color var(--transition-fast), background-color var(--transition-fast);
}

.hero__social a:hover,
.hero__social a:focus {
  color: var(--color-primary);
  background-color: var(--color-bg-alt);
}

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

/* Mobile: centered text */
@media (max-width: 767px) {
  .hero__container {
    text-align: center;
  }

  .hero__summary {
    margin-left: auto;
    margin-right: auto;
  }

  .hero__actions {
    display: flex;
    justify-content: center;
  }

  .hero__social {
    justify-content: center;
  }

  /* Reduce experience timeline padding on narrow screens */
  .experience__timeline {
    padding-left: var(--space-md);
  }

  .experience__entry {
    padding: var(--space-md);
  }

  .experience__entry::before {
    left: calc(-1 * var(--space-md) - 8px);
    top: var(--space-md);
  }
}

/* ==========================================================================
   Experience Section
   ========================================================================== */

.experience {
  padding-top: var(--space-section);
  padding-bottom: var(--space-section);
}

.section-heading {
  margin-bottom: var(--space-xl);
  padding-bottom: var(--space-sm);
}

/* Timeline container: vertical line on the left */
.experience__timeline {
  position: relative;
  padding-left: var(--space-lg);
  border-left: 3px solid var(--color-border);
}

/* Individual role entry */
.experience__entry {
  position: relative;
  padding: var(--space-lg);
  margin-bottom: var(--space-lg);
  background-color: var(--color-bg);
  border-radius: var(--border-radius);
  border: 1px solid var(--color-border);
}

.experience__entry:last-child {
  margin-bottom: 0;
}

/* Timeline dot connector */
.experience__entry::before {
  content: '';
  position: absolute;
  left: calc(-1 * var(--space-lg) - 8px);
  top: var(--space-lg);
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background-color: var(--color-border);
  border: 2px solid var(--color-bg);
}

/* Current role: visual distinction */
.experience__entry--current {
  background-color: var(--color-bg-alt);
  border-color: var(--color-primary);
  border-left: 3px solid var(--color-primary);
}

.experience__entry--current::before {
  background-color: var(--color-primary);
}

/* Header: title + badge */
.experience__header {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--space-sm);
  margin-bottom: var(--space-sm);
}

/* Role title */
.experience__title {
  font-size: var(--font-size-h3);
  font-weight: 700;
  color: var(--color-text);
}

/* "Current" badge: colored pill */
.experience__badge {
  display: inline-flex;
  align-items: center;
  padding: var(--space-xs) var(--space-sm);
  background-color: var(--color-primary);
  color: #ffffff;
  font-size: var(--font-size-sm);
  font-weight: 700;
  border-radius: 999px;
  line-height: 1;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

/* Meta text: company, location, dates */
.experience__meta {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  margin-bottom: var(--space-md);
}

/* Achievements bullet list */
.experience__achievements {
  list-style: disc;
  padding-left: var(--space-md);
  margin-bottom: var(--space-md);
}

.experience__achievements li {
  font-size: var(--font-size-base);
  line-height: var(--line-height);
  color: var(--color-text);
  margin-bottom: var(--space-sm);
  padding-left: var(--space-xs);
}

.experience__achievements li:last-child {
  margin-bottom: 0;
}

.experience__achievements li::marker {
  color: var(--color-primary);
}

/* Skills list */
.experience__skills {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  line-height: var(--line-height);
}

.experience__skills strong {
  color: var(--color-text);
  font-weight: 700;
}

/* ==========================================================================
   Blog Section
   ========================================================================== */

.blog__entry {
  padding-bottom: var(--space-lg);
  border-bottom: 1px solid var(--color-border);
}

.blog__entry:last-child {
  border-bottom: none;
  padding-bottom: 0;
}

.blog__entry h3 {
  margin-bottom: var(--space-xs);
}

.blog__date {
  display: block;
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  margin-bottom: var(--space-sm);
}

.blog__summary {
  font-size: var(--font-size-base);
  color: var(--color-text);
  line-height: var(--line-height);
}

.blog__placeholder {
  font-style: italic;
  color: var(--color-text-muted);
  text-align: center;
  padding: var(--space-xl) var(--space-md);
}

/* ==========================================================================
   Interests Section
   ========================================================================== */

.interests__category {
  background-color: var(--color-bg-alt);
  border: 1px solid var(--color-border);
  border-radius: var(--border-radius);
  padding: var(--space-lg);
}

.interests__category-title {
  margin-bottom: var(--space-md);
  color: var(--color-primary);
}

.interests__list {
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
}

.interests__item {
  display: flex;
  flex-direction: column;
  gap: var(--space-xs);
}

.interests__item strong {
  font-size: var(--font-size-base);
  font-weight: 700;
  color: var(--color-text);
}

.interests__item span {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  line-height: var(--line-height);
}

/* ==========================================================================
   Links Section
   ========================================================================== */

.links__category {
  background-color: var(--color-bg-alt);
  border: 1px solid var(--color-border);
  border-radius: var(--border-radius);
  padding: var(--space-lg);
}

.links__category-title {
  margin-bottom: var(--space-md);
  color: var(--color-primary);
  padding-bottom: var(--space-sm);
  border-bottom: 2px solid var(--color-border);
}

.links__list {
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
}

.links__item {
  padding: var(--space-md);
  background-color: var(--color-bg);
  border-radius: var(--border-radius);
  border: 1px solid var(--color-border);
  transition: border-color var(--transition-normal), box-shadow var(--transition-normal);
}

.links__item:hover {
  border-color: var(--color-primary);
  box-shadow: 0 2px 8px rgba(23, 114, 208, 0.1);
}

.links__url {
  display: inline-block;
  font-size: var(--font-size-base);
  font-weight: 700;
  color: var(--color-primary);
  text-decoration: none;
  margin-bottom: var(--space-xs);
  transition: color var(--transition-fast);
}

.links__url:hover,
.links__url:focus {
  color: var(--color-primary-hover);
}

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

.links__description {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  line-height: var(--line-height);
}

/* ==========================================================================
   Reading List Section
   ========================================================================== */

.reading-list__entries {
  list-style: none;
  padding: 0;
}

.reading-list__entry {
  padding: var(--space-lg);
  border-bottom: 1px solid var(--color-border);
}

.reading-list__entry:last-child {
  border-bottom: none;
}

.reading-list__name {
  display: inline-block;
  font-size: var(--font-size-lg);
  font-weight: 700;
  color: var(--color-primary);
  text-decoration: none;
  transition: color var(--transition-fast);
  margin-bottom: var(--space-sm);
}

.reading-list__name:hover,
.reading-list__name:focus {
  color: var(--color-primary-hover);
}

.reading-list__name:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
  border-radius: 2px;
}

.reading-list__description {
  font-size: var(--font-size-base);
  color: var(--color-text-muted);
  line-height: var(--line-height);
  margin-top: var(--space-xs);
}

/* ==========================================================================
   Footer
   ========================================================================== */

.site-footer {
  padding: var(--space-lg) var(--space-md);
  text-align: center;
  color: var(--color-text-muted);
  font-size: var(--font-size-sm);
  border-top: 1px solid var(--color-border);
  margin-top: var(--space-section);
}

.site-footer__copyright {
  margin-bottom: var(--space-xs);
}

.site-footer__location {
  margin-bottom: var(--space-md);
}

.site-footer__back-to-top {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 44px;
  min-height: 44px;
  color: var(--color-primary);
  font-size: var(--font-size-sm);
  font-weight: 400;
  text-decoration: none;
  transition: color var(--transition-fast);
}

.site-footer__back-to-top:hover,
.site-footer__back-to-top:focus {
  color: var(--color-primary-hover);
}

.site-footer__back-to-top:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
  border-radius: 2px;
}

/* ==========================================================================
   Blog Post Page Styles
   ========================================================================== */

.post-header__back {
  display: inline-flex;
  align-items: center;
  min-height: 44px;
  min-width: 44px;
  padding: var(--space-md);
  font-size: var(--font-size-base);
  color: var(--color-primary);
  text-decoration: none;
  transition: color var(--transition-fast);
}

.post-header__back:hover,
.post-header__back:focus {
  color: var(--color-primary-hover);
}

.post-header__back:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
  border-radius: 2px;
}

.post-content {
  padding-top: var(--space-xl);
  padding-bottom: var(--space-xl);
}

.post-content h1 {
  margin-bottom: var(--space-sm);
}

.post-content .blog__date {
  display: block;
  margin-bottom: var(--space-lg);
}

.post-content__body {
  margin-top: var(--space-lg);
}

.post-content__body p {
  margin-bottom: var(--space-md);
  line-height: var(--line-height);
}

.post-content__body h2 {
  margin-top: var(--space-xl);
  margin-bottom: var(--space-md);
}

.post-content__body h3 {
  margin-top: var(--space-lg);
  margin-bottom: var(--space-sm);
}

.post-content__body ul,
.post-content__body ol {
  list-style: disc;
  padding-left: var(--space-lg);
  margin-bottom: var(--space-md);
}

.post-content__body li {
  margin-bottom: var(--space-sm);
  line-height: var(--line-height);
}

.post-content__body code {
  background-color: var(--color-bg-alt);
  padding: 2px 6px;
  border-radius: 3px;
  font-size: var(--font-size-sm);
}

/* ==========================================================================
   Image Fallback Styles (Requirement 11.5)
   ========================================================================== */

img {
  background-color: var(--color-bg-alt);
}

/* ==========================================================================
   Responsive Layout - Tablet/Desktop (≥ 768px)
   ========================================================================== */

@media (min-width: 768px) {
  /* Hero: single column (no photo) */
  .hero__container {
    grid-template-columns: 1fr;
  }

  /* Experience: multi-column meta layout */
  .experience__header {
    display: flex;
    align-items: center;
    gap: var(--space-md);
  }

  /* Interests: auto-fill responsive grid */
  .interests__grid {
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  }

  /* Links: multi-column categories */
  .links__categories {
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  }
}

/* ==========================================================================
   Responsive Layout - Large Desktop (≥ 1200px)
   ========================================================================== */

@media (min-width: 1200px) {
  .site-main {
    padding-left: var(--space-lg);
    padding-right: var(--space-lg);
  }
}