/* DSIT Layout and Base Elements Rules */

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

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

body {
  font-family: var(--font-body);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  transition: background-color var(--transition-normal), color var(--transition-normal);
  overflow-x: hidden;
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  color: var(--text-primary);
  font-weight: 700;
  line-height: 1.25;
  margin-bottom: var(--space-sm);
}

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

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

/* --- LAYOUT WRAPPERS --- */

.container {
  width: 100%;
  max-width: var(--max-width-site);
  margin-left: auto;
  margin-right: auto;
  padding-left: var(--space-lg);
  padding-right: var(--space-lg);
}

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

.section-alt {
  background-color: var(--bg-secondary);
  padding-top: var(--space-section);
  padding-bottom: var(--space-section);
}

.section-header {
  max-width: 700px;
  margin-bottom: var(--space-xxl);
}

.section-header .tag {
  display: inline-block;
  color: var(--brand-sapphire);
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 0.875rem;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  margin-bottom: var(--space-sm);
}

.section-header h2 {
  font-size: 2.25rem;
  font-weight: 800;
}

@media (max-width: 768px) {
  .section-header h2 {
    font-size: 1.75rem;
  }
}

.section-header p {
  color: var(--text-secondary);
  font-size: 1.125rem;
}

/* --- NAVIGATION HEADER --- */

.header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: var(--header-height);
  background-color: rgba(255, 255, 255, 0.8);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-color);
  z-index: 1000;
  transition: background-color var(--transition-normal), border-color var(--transition-normal), height var(--transition-normal), box-shadow var(--transition-normal);
}

[data-theme="dark"] .header {
  background-color: rgba(11, 15, 25, 0.8);
}

.header.scrolled {
  height: 70px;
  box-shadow: var(--shadow-sm);
}

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

.logo-wrapper {
  display: flex;
  align-items: center;
  gap: 0;
  height: 100%;
}

.logo-img {
  height: 46px; /* Perfect vertical proportion inside header/footer navbar heights */
  width: auto;
  max-width: 170px;
  display: block;
  transition: filter var(--transition-normal), opacity var(--transition-normal);
}

.logo-dark-only {
  display: none !important;
}

.logo-light-only {
  display: block !important;
}

/* Dark Theme overrides */
[data-theme="dark"] .logo-light-only {
  display: none !important;
}

[data-theme="dark"] .logo-dark-only {
  display: block !important;
  filter: brightness(0) invert(1); /* Forces high-res black logo to pure, sharp white logo in dark mode */
}

/* Footer logo exclusions (always dark backdrop) */
.footer .logo-light-only {
  display: none !important;
}

.footer .logo-dark-only {
  display: block !important;
  filter: brightness(0) invert(1); /* Enforces crisp white logo regardless of global light theme selection */
}

.nav-menu {
  display: flex;
  align-items: center;
  gap: var(--space-xl);
  list-style: none;
}

.nav-link {
  font-family: var(--font-heading);
  font-weight: 500;
  font-size: 0.95rem;
  color: var(--text-secondary);
  position: relative;
  padding: var(--space-xs) 0;
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background-color: var(--brand-sapphire);
  transition: width var(--transition-fast);
}

.nav-link:hover, .nav-link.active {
  color: var(--text-primary);
}

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

.nav-actions {
  display: flex;
  align-items: center;
  gap: var(--space-lg);
}

/* Theme Switcher Toggle */
.theme-toggle {
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--space-xs);
  color: var(--text-secondary);
  border-radius: var(--border-radius-full);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: color var(--transition-fast), background-color var(--transition-fast);
}

.theme-toggle:hover {
  background-color: var(--bg-tertiary);
  color: var(--text-primary);
}

.theme-toggle svg {
  width: 20px;
  height: 20px;
}

.theme-toggle .sun-icon {
  display: none;
}

[data-theme="dark"] .theme-toggle .moon-icon {
  display: none;
}

[data-theme="dark"] .theme-toggle .sun-icon {
  display: block;
}

/* Hamburger mobile menu button */
.nav-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  color: var(--text-primary);
  padding: var(--space-xs);
}

.nav-toggle svg {
  width: 24px;
  height: 24px;
}

/* Responsive navigation styles */
@media (max-width: 992px) {
  .nav-toggle {
    display: block;
  }
  
  .nav-menu {
    position: fixed;
    top: var(--header-height);
    left: 0;
    width: 100%;
    height: calc(100vh - var(--header-height));
    background-color: var(--bg-primary);
    border-top: 1px solid var(--border-color);
    flex-direction: column;
    align-items: stretch;
    padding: var(--space-xl) var(--space-lg);
    gap: var(--space-lg);
    transform: translateY(-100%);
    opacity: 0;
    visibility: hidden;
    transition: transform var(--transition-normal), opacity var(--transition-normal), visibility var(--transition-normal);
    z-index: 999;
  }
  
  .nav-menu.open {
    transform: translateY(0);
    opacity: 1;
    visibility: visible;
  }

  .nav-link {
    font-size: 1.125rem;
    padding: var(--space-sm) 0;
    display: block;
    border-bottom: 1px solid var(--border-color);
  }

  .nav-link::after {
    display: none;
  }

  .nav-actions {
    width: 100%;
    justify-content: space-between;
    margin-top: var(--space-lg);
  }
}

/* --- FOOTER SECTION --- */

.footer {
  background-color: var(--brand-navy);
  color: #cbd5e1;
  padding-top: 5rem;
  padding-bottom: 2.5rem;
  border-top: 1px solid rgba(255, 255, 255, 0.05);
}

.footer-top {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr 1.5fr;
  gap: var(--space-xl);
  margin-bottom: 4rem;
}

@media (max-width: 992px) {
  .footer-top {
    grid-template-columns: 1fr 1fr;
    gap: var(--space-xl);
  }
}

@media (max-width: 576px) {
  .footer-top {
    grid-template-columns: 1fr;
  }
}

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

.footer-brand .logo-text {
  color: #ffffff;
}

.footer-brand p {
  font-size: 0.95rem;
  line-height: 1.5;
  color: #94a3b8;
  max-width: 280px;
}

.footer-socials {
  display: flex;
  gap: var(--space-md);
}

.footer-social-link {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: var(--border-radius-full);
  background-color: rgba(255, 255, 255, 0.05);
  color: #ffffff;
  transition: background-color var(--transition-fast), color var(--transition-fast), transform var(--transition-fast);
}

.footer-social-link:hover {
  background-color: var(--brand-sapphire);
  transform: translateY(-2px);
}

.footer-links-col {
  display: flex;
  flex-direction: column;
  gap: var(--space-lg);
}

.footer-links-col h4 {
  color: #ffffff;
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 1rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 0;
}

.footer-links {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
}

.footer-link {
  font-size: 0.95rem;
  color: #94a3b8;
  transition: color var(--transition-fast), padding-left var(--transition-fast);
}

.footer-link:hover {
  color: #ffffff;
  padding-left: 4px;
}

.footer-newsletter p {
  font-size: 0.9rem;
  color: #94a3b8;
  margin-bottom: var(--space-md);
}

.footer-newsletter-form {
  display: flex;
  position: relative;
}

.footer-newsletter-input {
  width: 100%;
  padding: 0.75rem 1rem;
  padding-right: 3rem;
  background-color: rgba(255, 255, 255, 0.05);
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: var(--border-radius-md);
  color: #ffffff;
  font-family: var(--font-body);
  font-size: 0.9rem;
  transition: border-color var(--transition-fast), background-color var(--transition-fast);
}

.footer-newsletter-input:focus {
  outline: none;
  border-color: var(--brand-sapphire);
  background-color: rgba(255, 255, 255, 0.08);
}

.footer-newsletter-btn {
  position: absolute;
  right: 4px;
  top: 4px;
  bottom: 4px;
  width: 32px;
  background-color: var(--brand-sapphire);
  border: none;
  border-radius: var(--border-radius-sm);
  color: #ffffff;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background-color var(--transition-fast);
}

.footer-newsletter-btn:hover {
  background-color: #3b82f6;
}

.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.05);
  padding-top: 2rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--space-md);
  font-size: 0.875rem;
  color: #64748b;
}

@media (max-width: 576px) {
  .footer-bottom {
    flex-direction: column;
    text-align: center;
  }
}

.footer-bottom-links {
  display: flex;
  gap: var(--space-lg);
}

.footer-bottom-link:hover {
  color: #ffffff;
}

/* --- GRID UTILITIES --- */
.grid-2 {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-xl);
}

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

.grid-4 {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--space-lg);
}

@media (max-width: 992px) {
  .grid-3, .grid-4 {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  .grid-2, .grid-3, .grid-4 {
    grid-template-columns: 1fr;
    gap: var(--space-lg);
  }
}