/* ===================================
   BASE STYLES
   Typography and Foundational Styles
   =================================== */

/* ========== BODY ========== */
body {
  font-family: var(--font-primary);
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-normal);
  line-height: var(--line-height-normal);
  color: var(--color-text-primary);
  background-color: var(--color-bg-primary);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* ========== TYPOGRAPHY ========== */

/* Headings */
h1,
h2,
h3,
h4,
h5,
h6 {
  font-family: var(--font-heading);
  font-weight: var(--font-weight-bold);
  line-height: var(--line-height-tight);
  letter-spacing: var(--letter-spacing-tight);
  color: var(--color-text-primary);
}

h1 {
  font-size: var(--font-size-4xl);
  margin-bottom: var(--spacing-md);
}

h2 {
  font-size: var(--font-size-3xl);
  margin-bottom: var(--spacing-md);
}

h3 {
  font-size: var(--font-size-2xl);
  margin-bottom: var(--spacing-sm);
}

h4 {
  font-size: var(--font-size-xl);
  margin-bottom: var(--spacing-sm);
}

h5 {
  font-size: var(--font-size-lg);
}

h6 {
  font-size: var(--font-size-md);
}

/* Paragraphs */
p {
  margin-bottom: var(--spacing-sm);
  color: var(--color-text-secondary);
}

/* Links */
a {
  color: var(--color-accent-blue);
  transition: color var(--transition-fast);
}

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

a:focus-visible {
  outline: 2px solid var(--color-accent-blue);
  outline-offset: 2px;
  border-radius: var(--radius-xs);
}

/* ========== UTILITY CLASSES ========== */

/* Container */
.container {
  max-width: var(--container-max-width);
  margin-left: auto;
  margin-right: auto;
  padding-left: var(--container-padding);
  padding-right: var(--container-padding);
}

/* Skip Link for Accessibility */
.skip-link {
  position: absolute;
  top: -40px;
  left: 0;
  background: var(--color-accent-blue);
  color: var(--color-text-white);
  padding: var(--spacing-xs) var(--spacing-sm);
  z-index: 9999;
  border-radius: var(--radius-sm);
  font-weight: var(--font-weight-semibold);
}

.skip-link:focus {
  top: 10px;
  left: 10px;
}

/* Gradient Text Effect */
.gradient-text {
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  background-size: 200% 200%;
  animation: gradient-shift 3s ease infinite;
}

/* Section Title */
.section-title {
  font-size: var(--font-size-3xl);
  font-weight: var(--font-weight-black);
  text-align: center;
  margin-bottom: var(--spacing-sm);
}

.section-subtitle {
  font-size: var(--font-size-lg);
  color: var(--color-text-secondary);
  text-align: center;
  margin-bottom: var(--spacing-lg);
  font-weight: var(--font-weight-normal);
}

/* Glassmorphism Card */
.glass-card {
  background: var(--glass-bg);
  backdrop-filter: var(--glass-blur);
  -webkit-backdrop-filter: var(--glass-blur);
  border-radius: var(--radius-lg);
  border: 1px solid var(--glass-border);
  box-shadow: var(--shadow-lg);
  padding: var(--spacing-md);
}

/* Scroll Progress Indicator */
.scroll-progress {
  position: fixed;
  top: 0;
  left: 0;
  width: 0%;
  height: 4px;
  background: var(--gradient-rainbow);
  z-index: var(--z-fixed);
  transition: width 0.1s ease-out;
}

/* Back to Top Button */
.back-to-top {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  width: 50px;
  height: 50px;
  border-radius: var(--radius-full);
  background: var(--gradient-primary);
  color: var(--color-text-white);
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: var(--shadow-lg);
  z-index: var(--z-fixed);
  opacity: 0;
  visibility: hidden;
  transform: translateY(20px);
  transition: all var(--transition-base);
}

.back-to-top.visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.back-to-top:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-xl);
}

/* ========== BUTTONS ========== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-xs);
  padding: 1rem 2rem;
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-semibold);
  border-radius: var(--radius-full);
  cursor: pointer;
  transition: all var(--transition-base);
  border: 2px solid transparent;
  white-space: nowrap;
  position: relative;
  overflow: hidden;
}

.btn--primary {
  background: var(--gradient-primary);
  color: var(--color-text-white);
  box-shadow: var(--shadow-md);
}

.btn--primary:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-glow-purple);
}

.btn--secondary {
  background: transparent;
  color: var(--color-text-primary);
  border: 2px solid var(--color-accent-blue);
}

.btn--secondary:hover {
  background: var(--gradient-primary);
  color: var(--color-text-white);
  border-color: transparent;
  transform: translateY(-3px);
}

.btn--full {
  width: 100%;
}

.btn:active {
  transform: translateY(0);
}

.btn:focus-visible {
  outline: 2px solid var(--color-accent-blue);
  outline-offset: 4px;
}

/* Button Loading State */
.btn__loader {
  display: none;
  width: 20px;
  height: 20px;
  border: 2px solid rgba(255, 255, 255, 0.3);
  border-top-color: var(--color-text-white);
  border-radius: var(--radius-full);
  animation: spin 0.6s linear infinite;
}

.btn.loading .btn__text {
  display: none;
}

.btn.loading .btn__loader {
  display: block;
}

@keyframes spin {
  to {
    transform: rotate(360deg);
  }
}

/* ========== HEADER ========== */
.header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: var(--header-height);
  background: rgba(255, 255, 255, 0.9);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  box-shadow: var(--shadow-sm);
  z-index: var(--z-sticky);
  transition: all var(--transition-base);
}

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

.header__logo {
  font-size: var(--font-size-xl);
  font-weight: var(--font-weight-bold);
  z-index: var(--z-dropdown);
}

/* Navigation */
.nav__list {
  display: flex;
  gap: var(--spacing-md);
}

.nav__link {
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-medium);
  color: var(--color-text-primary);
  padding: var(--spacing-xs) var(--spacing-sm);
  border-radius: var(--radius-sm);
  position: relative;
  transition: all var(--transition-fast);
}

.nav__link::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 0;
  height: 2px;
  background: var(--gradient-primary);
  transition: width var(--transition-base);
}

.nav__link:hover::after,
.nav__link.active::after {
  width: 80%;
}

.nav__link.active {
  color: var(--color-accent-blue);
}

/* Mobile Toggle */
.mobile-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  z-index: var(--z-dropdown);
}

.mobile-toggle__line {
  width: 25px;
  height: 3px;
  background: var(--gradient-primary);
  border-radius: var(--radius-full);
  transition: all var(--transition-base);
}

.mobile-toggle.active .mobile-toggle__line:nth-child(1) {
  transform: rotate(45deg) translateY(8px);
}

.mobile-toggle.active .mobile-toggle__line:nth-child(2) {
  opacity: 0;
}

.mobile-toggle.active .mobile-toggle__line:nth-child(3) {
  transform: rotate(-45deg) translateY(-8px);
}

/* ========== FOOTER ========== */
.footer {
  background: var(--color-bg-dark);
  color: var(--color-text-white);
  padding: var(--spacing-md);
  text-align: center;
  margin-top: var(--spacing-xl);
}

.footer p {
  color: var(--color-text-white);
  margin: 0;
}

/* ========== ANIMATIONS ========== */

/* Fade In Animation */
.animate-on-scroll {
  opacity: 0;
  transform: translateY(30px);
  transition: all var(--transition-slow);
}

.animate-on-scroll.animate-in {
  opacity: 1;
  transform: translateY(0);
}

/* Stagger Animation Delays */
.animate-on-scroll:nth-child(1) { transition-delay: 0s; }
.animate-on-scroll:nth-child(2) { transition-delay: 0.1s; }
.animate-on-scroll:nth-child(3) { transition-delay: 0.2s; }
.animate-on-scroll:nth-child(4) { transition-delay: 0.3s; }
.animate-on-scroll:nth-child(5) { transition-delay: 0.4s; }
.animate-on-scroll:nth-child(6) { transition-delay: 0.5s; }