/* ===========================
   CSS Custom Properties
   =========================== */
:root {
  --color-primary: #1a5276;
  --color-primary-dark: #0e3a55;
  --color-primary-light: #2980b9;
  --color-accent: #2471a3;
  --color-text: #1a1a2e;
  --color-text-light: #4a4a5a;
  --color-bg: #ffffff;
  --color-bg-alt: #f4f6f9;
  --color-border: #d5dbe3;
  --color-focus: #2471a3;
  --color-card-bg: #ffffff;
  --font-primary: 'Segoe UI', system-ui, -apple-system, sans-serif;
  --font-heading: Georgia, 'Times New Roman', serif;
  --max-width: 1100px;
  --spacing-xs: 0.5rem;
  --spacing-sm: 1rem;
  --spacing-md: 2rem;
  --spacing-lg: 3rem;
  --spacing-xl: 5rem;
  --radius: 8px;
  --shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 4px 20px rgba(0, 0, 0, 0.12);
  --transition: 0.2s ease;
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: 80px;
}

body {
  font-family: var(--font-primary);
  font-size: 1.0625rem;
  line-height: 1.7;
  color: var(--color-text);
  background-color: var(--color-bg);
  -webkit-font-smoothing: antialiased;
}

/* ===========================
   Accessibility: Skip Link
   =========================== */
.skip-link {
  position: absolute;
  top: -100%;
  left: 50%;
  transform: translateX(-50%);
  background: var(--color-primary);
  color: #fff;
  padding: 0.75rem 1.5rem;
  border-radius: 0 0 var(--radius) var(--radius);
  font-weight: 600;
  text-decoration: none;
  z-index: 10000;
  transition: top var(--transition);
}

.skip-link:focus {
  top: 0;
  outline: 3px solid var(--color-focus);
  outline-offset: 2px;
}

/* Screen reader only */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* ===========================
   Focus Styles (Accessibility)
   =========================== */
:focus-visible {
  outline: 3px solid var(--color-focus);
  outline-offset: 3px;
}

a:focus:not(:focus-visible),
button:focus:not(:focus-visible) {
  outline: none;
}

/* ===========================
   Typography
   =========================== */
h1, h2, h3, h4 {
  font-family: var(--font-heading);
  line-height: 1.3;
  color: var(--color-primary-dark);
}

h1 { font-size: clamp(2.25rem, 5vw, 3.5rem); }
h2 { font-size: clamp(1.75rem, 3.5vw, 2.25rem); margin-bottom: var(--spacing-md); }
h3 { font-size: 1.25rem; }
h4 { font-size: 1.1rem; color: var(--color-accent); }

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

a {
  color: var(--color-primary-light);
  text-decoration: underline;
  text-underline-offset: 3px;
  transition: color var(--transition);
}

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

/* ===========================
   Layout
   =========================== */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--spacing-md);
}

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

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

.section-intro {
  font-size: 1.125rem;
  color: var(--color-text-light);
  max-width: 600px;
  margin-bottom: var(--spacing-lg);
}

/* ===========================
   Navigation
   =========================== */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  background: rgba(255, 255, 255, 0.97);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--color-border);
  z-index: 1000;
  padding: 0.75rem 0;
}

.nav-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.logo {
  font-family: var(--font-heading);
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--color-primary);
  text-decoration: none;
  letter-spacing: 0.02em;
}

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

.nav-links {
  display: flex;
  list-style: none;
  gap: var(--spacing-md);
}

.nav-links a {
  text-decoration: none;
  color: var(--color-text);
  font-weight: 500;
  font-size: 0.95rem;
  padding: 0.5rem 0;
  position: relative;
}

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

.nav-links a:hover::after,
.nav-links a:focus-visible::after {
  width: 100%;
}

/* Hamburger */
.nav-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.5rem;
  width: 44px;
  height: 44px;
  align-items: center;
  justify-content: center;
}

.hamburger,
.hamburger::before,
.hamburger::after {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--color-text);
  transition: all var(--transition);
}

.hamburger {
  position: relative;
}

.hamburger::before,
.hamburger::after {
  content: '';
  position: absolute;
  left: 0;
}

.hamburger::before { top: -7px; }
.hamburger::after { top: 7px; }

/* Active hamburger */
.nav-toggle[aria-expanded="true"] .hamburger {
  background: transparent;
}

.nav-toggle[aria-expanded="true"] .hamburger::before {
  top: 0;
  transform: rotate(45deg);
}

.nav-toggle[aria-expanded="true"] .hamburger::after {
  top: 0;
  transform: rotate(-45deg);
}

/* ===========================
   Buttons
   =========================== */
.btn {
  display: inline-block;
  padding: 0.8rem 1.75rem;
  border-radius: var(--radius);
  font-size: 1rem;
  font-weight: 600;
  text-decoration: none;
  cursor: pointer;
  border: 2px solid transparent;
  transition: all var(--transition);
  min-height: 44px;
  text-align: center;
}

.btn-primary {
  background: var(--color-primary);
  color: #fff;
  border-color: var(--color-primary);
}

.btn-primary:hover {
  background: var(--color-primary-dark);
  border-color: var(--color-primary-dark);
  color: #fff;
}

.btn-outline {
  background: transparent;
  color: var(--color-primary);
  border-color: var(--color-primary);
}

.btn-outline:hover {
  background: var(--color-primary);
  color: #fff;
}

/* ===========================
   Hero
   =========================== */
.hero {
  min-height: 90vh;
  display: flex;
  align-items: center;
  padding-top: 80px;
  background: linear-gradient(165deg, var(--color-bg) 60%, var(--color-bg-alt) 100%);
}

.hero-content {
  max-width: 700px;
}

.hero-greeting {
  font-size: 1.125rem;
  color: var(--color-accent);
  font-weight: 500;
  margin-bottom: var(--spacing-xs);
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

.hero h1 {
  margin-bottom: var(--spacing-sm);
}

.hero-title {
  font-size: clamp(1.125rem, 2.5vw, 1.375rem);
  color: var(--color-text-light);
  font-weight: 500;
  margin-bottom: var(--spacing-xs);
}

.hero-subtitle {
  font-size: 1.0625rem;
  color: var(--color-text-light);
  margin-bottom: var(--spacing-md);
}

.hero-cta {
  display: flex;
  gap: var(--spacing-sm);
  flex-wrap: wrap;
}

/* ===========================
   About
   =========================== */
.about-content {
  display: grid;
  grid-template-columns: 1fr 280px;
  gap: var(--spacing-lg);
  align-items: start;
}

.about-text p {
  font-size: 1.0625rem;
}

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

.highlight-card {
  background: var(--color-bg-alt);
  padding: var(--spacing-sm) var(--spacing-md);
  border-radius: var(--radius);
  border-left: 4px solid var(--color-primary);
  text-align: center;
}

.highlight-number {
  display: block;
  font-size: 2rem;
  font-weight: 700;
  color: var(--color-primary);
  font-family: var(--font-heading);
  line-height: 1.2;
}

.highlight-label {
  font-size: 0.9rem;
  color: var(--color-text-light);
}

/* ===========================
   Cards Grid
   =========================== */
.cards-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: var(--spacing-md);
}

.card {
  background: var(--color-card-bg);
  padding: var(--spacing-md);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  transition: box-shadow var(--transition), transform var(--transition);
}

.card:hover {
  box-shadow: var(--shadow-lg);
  transform: translateY(-2px);
}

.card-icon {
  color: var(--color-primary);
  margin-bottom: var(--spacing-sm);
}

.card h3 {
  margin-bottom: var(--spacing-xs);
}

.card p {
  color: var(--color-text-light);
  font-size: 0.95rem;
}

/* ===========================
   Timeline
   =========================== */
.timeline {
  position: relative;
  padding-left: 2rem;
}

.timeline::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 2px;
  background: var(--color-border);
}

.timeline-item {
  position: relative;
  margin-bottom: var(--spacing-lg);
}

.timeline-item:last-child {
  margin-bottom: 0;
}

.timeline-marker {
  position: absolute;
  left: -2rem;
  top: 0.3rem;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--color-primary);
  border: 3px solid var(--color-bg);
  box-shadow: 0 0 0 2px var(--color-primary);
  transform: translateX(-6px);
}

.timeline-content {
  background: var(--color-bg-alt);
  padding: var(--spacing-md);
  border-radius: var(--radius);
  border-left: 3px solid var(--color-primary);
}

.timeline-header {
  margin-bottom: var(--spacing-sm);
}

.timeline-header h3 {
  margin-bottom: 0.25rem;
}

.timeline-company {
  color: var(--color-accent);
  font-weight: 500;
  margin-bottom: 0.25rem;
}

.timeline-date {
  font-size: 0.9rem;
  color: var(--color-text-light);
  margin-bottom: 0;
}

.timeline-details h4 {
  margin-top: var(--spacing-sm);
  margin-bottom: var(--spacing-xs);
}

.timeline-details ul {
  padding-left: 1.25rem;
  margin-bottom: var(--spacing-xs);
}

.timeline-details li {
  margin-bottom: 0.4rem;
  font-size: 0.95rem;
  color: var(--color-text-light);
}

/* ===========================
   Skills
   =========================== */
.skills-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--spacing-md);
}

.skill-group {
  background: var(--color-card-bg);
  padding: var(--spacing-md);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.skill-group h3 {
  margin-bottom: var(--spacing-sm);
  padding-bottom: var(--spacing-xs);
  border-bottom: 2px solid var(--color-primary);
}

.skill-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  list-style: none;
}

.skill-tags li {
  background: var(--color-bg-alt);
  color: var(--color-text);
  padding: 0.35rem 0.85rem;
  border-radius: 20px;
  font-size: 0.875rem;
  font-weight: 500;
  border: 1px solid var(--color-border);
}

/* ===========================
   Recognition
   =========================== */
.recognition-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--spacing-lg);
}

.recognition-col h3 {
  margin-bottom: var(--spacing-sm);
  padding-bottom: var(--spacing-xs);
  border-bottom: 2px solid var(--color-primary);
}

.recognition-col h3:not(:first-child) {
  margin-top: var(--spacing-md);
}

.recognition-list {
  list-style: none;
  padding: 0;
}

.recognition-list li {
  padding: var(--spacing-xs) 0;
  border-bottom: 1px solid var(--color-border);
  font-size: 0.95rem;
}

.recognition-list li:last-child {
  border-bottom: none;
}

/* ===========================
   Contact
   =========================== */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--spacing-lg);
  align-items: start;
}

.contact-info address {
  font-style: normal;
}

.contact-item {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-sm) 0;
  border-bottom: 1px solid var(--color-border);
}

.contact-item:last-child {
  border-bottom: none;
}

.contact-item svg {
  flex-shrink: 0;
  color: var(--color-primary);
}

.contact-form {
  background: var(--color-card-bg);
  padding: var(--spacing-md);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.form-group {
  margin-bottom: var(--spacing-sm);
}

.form-group label {
  display: block;
  font-weight: 600;
  margin-bottom: 0.35rem;
  font-size: 0.95rem;
}

.form-group input,
.form-group textarea {
  width: 100%;
  padding: 0.7rem 0.85rem;
  border: 2px solid var(--color-border);
  border-radius: var(--radius);
  font-family: var(--font-primary);
  font-size: 1rem;
  color: var(--color-text);
  background: var(--color-bg);
  transition: border-color var(--transition);
  min-height: 44px;
}

.form-group input:focus,
.form-group textarea:focus {
  border-color: var(--color-focus);
  outline: 2px solid var(--color-focus);
  outline-offset: 1px;
}

.form-group input[aria-invalid="true"],
.form-group textarea[aria-invalid="true"] {
  border-color: #c0392b;
}

.form-error {
  color: #c0392b;
  font-size: 0.85rem;
  margin-top: 0.25rem;
}

/* ===========================
   Library Section
   =========================== */
.library-gate {
  text-align: center;
  padding: var(--spacing-xl) var(--spacing-md);
  background: var(--color-bg-alt);
  border-radius: var(--radius);
  border: 2px dashed var(--color-border);
}

.library-gate-content {
  max-width: 500px;
  margin: 0 auto;
}

.library-gate-content svg {
  color: var(--color-primary);
  margin-bottom: var(--spacing-sm);
}

.library-gate-content h3 {
  margin-bottom: var(--spacing-xs);
}

.library-gate-content p {
  color: var(--color-text-light);
  margin-bottom: var(--spacing-md);
}

.library-gate-actions {
  display: flex;
  gap: var(--spacing-sm);
  justify-content: center;
  flex-wrap: wrap;
}

.library-toolbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--spacing-md);
  flex-wrap: wrap;
  gap: var(--spacing-sm);
}

.library-user-info {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  font-weight: 500;
}

.btn-text {
  background: none;
  border: none;
  color: var(--color-primary-light);
  cursor: pointer;
  font-size: inherit;
  font-family: inherit;
  text-decoration: underline;
  text-underline-offset: 3px;
  padding: 0.25rem;
  min-height: 44px;
  display: inline-flex;
  align-items: center;
}

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

.library-filters {
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
}

.filter-btn {
  background: var(--color-bg-alt);
  border: 2px solid var(--color-border);
  border-radius: 20px;
  padding: 0.4rem 1rem;
  font-size: 0.875rem;
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition);
  min-height: 44px;
  font-family: var(--font-primary);
  color: var(--color-text);
}

.filter-btn:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
}

.filter-btn.active {
  background: var(--color-primary);
  border-color: var(--color-primary);
  color: #fff;
}

.library-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: var(--spacing-md);
}

.library-card {
  background: var(--color-card-bg);
  border-radius: var(--radius);
  padding: var(--spacing-md);
  box-shadow: var(--shadow);
  display: flex;
  flex-direction: column;
  transition: box-shadow var(--transition);
}

.library-card:hover {
  box-shadow: var(--shadow-lg);
}

.library-card-badge {
  display: inline-block;
  background: var(--color-bg-alt);
  color: var(--color-accent);
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  padding: 0.2rem 0.6rem;
  border-radius: 4px;
  margin-bottom: var(--spacing-xs);
  align-self: flex-start;
}

.library-card h3 {
  margin-bottom: var(--spacing-xs);
  font-size: 1.1rem;
}

.library-card p {
  color: var(--color-text-light);
  font-size: 0.9rem;
  flex-grow: 1;
}

.library-card-meta {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: var(--spacing-sm);
  padding-top: var(--spacing-xs);
  border-top: 1px solid var(--color-border);
  font-size: 0.85rem;
  color: var(--color-text-light);
}

/* ===========================
   Auth Modal
   =========================== */
.modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.6);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 2000;
  padding: var(--spacing-md);
}

.modal-overlay[hidden] {
  display: none;
}

.modal {
  background: var(--color-bg);
  border-radius: var(--radius);
  padding: var(--spacing-lg);
  max-width: 460px;
  width: 100%;
  position: relative;
  box-shadow: var(--shadow-lg);
  max-height: 90vh;
  overflow-y: auto;
}

.modal h2 {
  margin-bottom: var(--spacing-xs);
}

.modal > div > p:first-of-type {
  color: var(--color-text-light);
  margin-bottom: var(--spacing-md);
}

.modal-close {
  position: absolute;
  top: 1rem;
  right: 1rem;
  background: none;
  border: none;
  font-size: 1.75rem;
  color: var(--color-text-light);
  cursor: pointer;
  width: 44px;
  height: 44px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius);
  line-height: 1;
}

.modal-close:hover {
  background: var(--color-bg-alt);
  color: var(--color-text);
}

.btn-full {
  width: 100%;
}

.auth-switch {
  text-align: center;
  margin-top: var(--spacing-sm);
  font-size: 0.9rem;
  color: var(--color-text-light);
}

/* ===========================
   Footer
   =========================== */
.footer {
  background: var(--color-primary-dark);
  color: #e0e0e0;
  padding: var(--spacing-md) 0;
  text-align: center;
}

.footer p {
  font-size: 0.9rem;
  margin-bottom: 0.25rem;
}

.footer-note {
  font-size: 0.8rem;
  opacity: 0.75;
}

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

  .nav-links {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: var(--color-bg);
    flex-direction: column;
    padding: var(--spacing-sm) var(--spacing-md);
    gap: 0;
    border-bottom: 1px solid var(--color-border);
    display: none;
    box-shadow: var(--shadow-lg);
  }

  .nav-links.active {
    display: flex;
  }

  .nav-links a {
    padding: 0.75rem 0;
    display: block;
  }

  .about-content {
    grid-template-columns: 1fr;
  }

  .about-highlights {
    flex-direction: row;
    flex-wrap: wrap;
  }

  .highlight-card {
    flex: 1;
    min-width: 120px;
  }

  .recognition-grid,
  .contact-grid {
    grid-template-columns: 1fr;
  }

  .hero {
    min-height: 70vh;
  }
}

@media (max-width: 480px) {
  .hero-cta {
    flex-direction: column;
  }

  .btn {
    width: 100%;
  }
}

/* ===========================
   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;
  }
}

/* ===========================
   High Contrast Mode
   =========================== */
@media (forced-colors: active) {
  .btn {
    border: 2px solid ButtonText;
  }

  .timeline-marker {
    forced-color-adjust: none;
  }

  .card,
  .skill-group,
  .contact-form,
  .library-card,
  .modal {
    border: 1px solid ButtonText;
  }
}

/* ===========================
   Print Styles
   =========================== */
@media print {
  .navbar,
  .nav-toggle,
  .skip-link,
  .contact-form,
  .hero-cta {
    display: none;
  }

  body {
    font-size: 12pt;
    color: #000;
    background: #fff;
  }

  .section {
    padding: 1rem 0;
  }

  a[href]::after {
    content: " (" attr(href) ")";
    font-size: 0.8em;
    color: #666;
  }
}