/*
 * Dhitantra Technologies - Main Stylesheet
 * Modern, responsive design system for marketing website
 */

/* ============================================
   CSS CUSTOM PROPERTIES (Design Tokens)
   ============================================ */
:root {
  /* Brand Colors - Extracted from Logo */
  --color-primary: #005A9C;        /* Dark blue - DHITANTRA text */
  --color-secondary: #3FA9D3;      /* Light blue - cloud icon */
  --color-accent: #2B88B8;         /* Medium blue - accents */
  --color-primary-dark: #004275;   /* Darker shade for hover */
  --color-primary-light: #0073C6;  /* Lighter shade */
  
  /* Neutral Colors */
  --color-bg: #FFFFFF;
  --color-bg-alt: #F5F5F5;
  --color-bg-dark: #E8E8E8;
  --color-text: #333333;
  --color-text-light: #666666;
  --color-text-muted: #999999;
  --color-border: #DDDDDD;
  
  /* Semantic Colors */
  --color-success: #28A745;
  --color-error: #DC3545;
  --color-warning: #FFC107;
  --color-info: #17A2B8;
  
  /* Typography */
  --font-primary: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
  --font-heading: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  
  --font-size-xs: 0.75rem;      /* 12px */
  --font-size-sm: 0.875rem;     /* 14px */
  --font-size-base: 1rem;       /* 16px */
  --font-size-lg: 1.125rem;     /* 18px */
  --font-size-xl: 1.25rem;      /* 20px */
  --font-size-2xl: 1.5rem;      /* 24px */
  --font-size-3xl: 1.875rem;    /* 30px */
  --font-size-4xl: 2.25rem;     /* 36px */
  --font-size-5xl: 3rem;        /* 48px */
  
  --font-weight-normal: 400;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;
  --font-weight-bold: 700;
  
  --line-height-tight: 1.25;
  --line-height-normal: 1.5;
  --line-height-relaxed: 1.75;
  
  /* Spacing Scale */
  --space-xs: 0.25rem;    /* 4px */
  --space-sm: 0.5rem;     /* 8px */
  --space-md: 1rem;       /* 16px */
  --space-lg: 1.5rem;     /* 24px */
  --space-xl: 2rem;       /* 32px */
  --space-2xl: 3rem;      /* 48px */
  --space-3xl: 4rem;      /* 64px */
  --space-4xl: 6rem;      /* 96px */
  
  /* Layout */
  --container-max: 1280px;
  --container-padding: var(--space-md);
  --section-padding: var(--space-3xl);
  
  /* Border Radius */
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-xl: 16px;
  --radius-full: 9999px;
  
  /* Shadows */
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
  
  /* Transitions */
  --transition-fast: 150ms ease-in-out;
  --transition-base: 250ms ease-in-out;
  --transition-slow: 350ms ease-in-out;
  
  /* Z-index Scale */
  --z-dropdown: 1000;
  --z-sticky: 1020;
  --z-fixed: 1030;
  --z-modal-backdrop: 1040;
  --z-modal: 1050;
  --z-popover: 1060;
  --z-tooltip: 1070;
}

/* ============================================
   RESET & BASE STYLES
   ============================================ */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

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);
  background-color: var(--color-bg);
  overflow-x: hidden;
}

/* ============================================
   TYPOGRAPHY
   ============================================ */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  font-weight: var(--font-weight-bold);
  line-height: var(--line-height-tight);
  color: var(--color-primary);
  margin-bottom: var(--space-md);
}

h1 {
  font-size: var(--font-size-4xl);
  margin-bottom: var(--space-lg);
}

h2 {
  font-size: var(--font-size-3xl);
}

h3 {
  font-size: var(--font-size-2xl);
}

h4 {
  font-size: var(--font-size-xl);
}

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

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

p {
  margin-bottom: var(--space-md);
  color: var(--color-text);
}

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

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

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

strong, b {
  font-weight: var(--font-weight-bold);
}

em, i {
  font-style: italic;
}

/* ============================================
   LAYOUT COMPONENTS
   ============================================ */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin-left: auto;
  margin-right: auto;
  padding-left: var(--container-padding);
  padding-right: var(--container-padding);
}

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

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

/* ============================================
   HEADER & NAVIGATION
   ============================================ */
.header {
  position: sticky;
  top: 0;
  z-index: var(--z-sticky);
  background-color: var(--color-bg);
  box-shadow: var(--shadow-sm);
  transition: box-shadow var(--transition-base);
}

.header.scrolled {
  box-shadow: var(--shadow-md);
}

.header__container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: var(--space-md);
  padding-bottom: var(--space-md);
}

.header__logo {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.header__logo-img {
  height: 48px;
  width: auto;
}

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

.nav__list {
  display: flex;
  align-items: center;
  gap: var(--space-lg);
  list-style: none;
}

.nav__link {
  font-weight: var(--font-weight-medium);
  color: var(--color-text);
  padding: var(--space-sm) var(--space-md);
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
}

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

.nav__link.active {
  color: var(--color-primary);
  font-weight: var(--font-weight-semibold);
}

/* Mobile Navigation Toggle */
.nav__toggle {
  display: none;
  flex-direction: column;
  gap: 4px;
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--space-sm);
  z-index: var(--z-fixed);
}

.nav__toggle-bar {
  width: 24px;
  height: 3px;
  background-color: var(--color-primary);
  border-radius: var(--radius-full);
  transition: all var(--transition-base);
}

.nav__toggle.active .nav__toggle-bar:nth-child(1) {
  transform: rotate(45deg) translate(5px, 5px);
}

.nav__toggle.active .nav__toggle-bar:nth-child(2) {
  opacity: 0;
}

.nav__toggle.active .nav__toggle-bar:nth-child(3) {
  transform: rotate(-45deg) translate(7px, -6px);
}

/* ============================================
   BUTTONS
   ============================================ */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
  padding: var(--space-md) var(--space-xl);
  font-family: var(--font-primary);
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-semibold);
  line-height: 1;
  text-align: center;
  text-decoration: none;
  border: 2px solid transparent;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all var(--transition-base);
  white-space: nowrap;
}

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

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

.btn--primary:hover {
  background-color: var(--color-primary-dark);
  border-color: var(--color-primary-dark);
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

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

.btn--secondary:hover {
  color: #FFFFFF;
  background-color: var(--color-primary);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.btn--accent {
  color: #FFFFFF;
  background-color: var(--color-accent);
  border-color: var(--color-accent);
}

.btn--accent:hover {
  background-color: var(--color-secondary);
  border-color: var(--color-secondary);
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

.btn--lg {
  padding: var(--space-lg) var(--space-2xl);
  font-size: var(--font-size-lg);
}

.btn--sm {
  padding: var(--space-sm) var(--space-lg);
  font-size: var(--font-size-sm);
}

/* ============================================
   HERO CAROUSEL
   ============================================ */
.hero-carousel {
  position: relative;
  width: 100%;
  height: 600px;
  overflow: hidden;
  background-color: var(--color-bg-dark);
}

.hero-carousel__track {
  display: flex;
  height: 100%;
  transition: transform var(--transition-slow);
}

.hero-carousel__slide {
  flex: 0 0 100%;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
  background-size: cover;
  background-position: center;
}

.hero-carousel__slide::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, rgba(0, 90, 156, 0.85) 0%, rgba(43, 136, 184, 0.75) 100%);
}

.hero-carousel__content {
  position: relative;
  z-index: 1;
  text-align: center;
  color: #FFFFFF;
  max-width: 800px;
  padding: var(--space-xl);
}

.hero-carousel__title {
  font-size: var(--font-size-5xl);
  color: #FFFFFF;
  margin-bottom: var(--space-lg);
  text-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
}

.hero-carousel__description {
  font-size: var(--font-size-xl);
  color: #FFFFFF;
  margin-bottom: var(--space-2xl);
  opacity: 0.95;
}

.hero-carousel__controls {
  position: absolute;
  bottom: var(--space-xl);
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  gap: var(--space-md);
  z-index: 2;
}

.hero-carousel__dot {
  width: 12px;
  height: 12px;
  border-radius: var(--radius-full);
  background-color: rgba(255, 255, 255, 0.5);
  border: none;
  cursor: pointer;
  transition: all var(--transition-base);
}

.hero-carousel__dot:hover {
  background-color: rgba(255, 255, 255, 0.75);
  transform: scale(1.2);
}

.hero-carousel__dot.active {
  background-color: #FFFFFF;
  width: 32px;
}

.hero-carousel__nav {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  background-color: rgba(255, 255, 255, 0.2);
  backdrop-filter: blur(4px);
  border: none;
  color: #FFFFFF;
  font-size: var(--font-size-2xl);
  width: 48px;
  height: 48px;
  border-radius: var(--radius-full);
  cursor: pointer;
  transition: all var(--transition-base);
  z-index: 2;
}

.hero-carousel__nav:hover {
  background-color: rgba(255, 255, 255, 0.3);
  transform: translateY(-50%) scale(1.1);
}

.hero-carousel__nav--prev {
  left: var(--space-xl);
}

.hero-carousel__nav--next {
  right: var(--space-xl);
}

/* ============================================
   CARDS
   ============================================ */
.card {
  background-color: var(--color-bg);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
  overflow: hidden;
  transition: all var(--transition-base);
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-xl);
}

.card__image {
  width: 100%;
  height: 200px;
  object-fit: cover;
}

.card__content {
  padding: var(--space-xl);
}

.card__icon {
  width: 64px;
  height: 64px;
  margin-bottom: var(--space-md);
  color: var(--color-secondary);
}

.card__title {
  font-size: var(--font-size-xl);
  margin-bottom: var(--space-md);
}

.card__description {
  color: var(--color-text-light);
  margin-bottom: var(--space-lg);
}

.card__link {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  color: var(--color-accent);
  font-weight: var(--font-weight-semibold);
  transition: gap var(--transition-fast);
}

.card__link:hover {
  gap: var(--space-md);
}

/* ============================================
   GRID LAYOUTS
   ============================================ */
.grid {
  display: grid;
  gap: var(--space-xl);
}

.grid--2 {
  grid-template-columns: repeat(2, 1fr);
}

.grid--3 {
  grid-template-columns: repeat(3, 1fr);
}

.grid--4 {
  grid-template-columns: repeat(4, 1fr);
}

/* ============================================
   FORMS
   ============================================ */
.form {
  width: 100%;
}

.form__group {
  margin-bottom: var(--space-lg);
}

.form__label {
  display: block;
  font-weight: var(--font-weight-medium);
  margin-bottom: var(--space-sm);
  color: var(--color-text);
}

.form__label--required::after {
  content: '*';
  color: var(--color-error);
  margin-left: var(--space-xs);
}

.form__input,
.form__textarea,
.form__select {
  width: 100%;
  padding: var(--space-md);
  font-family: var(--font-primary);
  font-size: var(--font-size-base);
  color: var(--color-text);
  background-color: var(--color-bg);
  border: 2px solid var(--color-border);
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
}

.form__input:focus,
.form__textarea:focus,
.form__select:focus {
  outline: none;
  border-color: var(--color-accent);
  box-shadow: 0 0 0 3px rgba(43, 136, 184, 0.1);
}

.form__input.error,
.form__textarea.error,
.form__select.error {
  border-color: var(--color-error);
}

.form__textarea {
  min-height: 120px;
  resize: vertical;
}

.form__error {
  display: block;
  margin-top: var(--space-sm);
  font-size: var(--font-size-sm);
  color: var(--color-error);
}

.form__success {
  padding: var(--space-md);
  background-color: rgba(40, 167, 69, 0.1);
  border: 1px solid var(--color-success);
  border-radius: var(--radius-md);
  color: var(--color-success);
  margin-bottom: var(--space-lg);
}

/* ============================================
   FOOTER
   ============================================ */
.footer {
  background-color: var(--color-primary);
  color: #FFFFFF;
  padding-top: var(--space-3xl);
  padding-bottom: var(--space-xl);
}

.footer__grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: var(--space-2xl);
  margin-bottom: var(--space-2xl);
}

.footer__section-title {
  color: #FFFFFF;
  font-size: var(--font-size-lg);
  margin-bottom: var(--space-md);
}

.footer__list {
  list-style: none;
}

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

.footer__link {
  color: rgba(255, 255, 255, 0.8);
  transition: color var(--transition-fast);
}

.footer__link:hover {
  color: #FFFFFF;
}

.footer__bottom {
  padding-top: var(--space-xl);
  border-top: 1px solid rgba(255, 255, 255, 0.2);
  text-align: center;
  color: rgba(255, 255, 255, 0.7);
  font-size: var(--font-size-sm);
}

/* ============================================
   CTA SECTION
   ============================================ */
.cta {
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-accent) 100%);
  color: #FFFFFF;
  text-align: center;
  padding: var(--space-3xl) var(--space-xl);
  border-radius: var(--radius-xl);
}

.cta__title {
  color: #FFFFFF;
  font-size: var(--font-size-3xl);
  margin-bottom: var(--space-md);
}

.cta__description {
  color: rgba(255, 255, 255, 0.9);
  font-size: var(--font-size-lg);
  margin-bottom: var(--space-2xl);
}

.cta__buttons {
  display: flex;
  gap: var(--space-lg);
  justify-content: center;
  flex-wrap: wrap;
}

/* ============================================
   RESPONSIVE BREAKPOINTS
   ============================================ */

/* Tablet (768px) */
@media (max-width: 768px) {
  :root {
    --font-size-4xl: 2rem;
    --font-size-5xl: 2.5rem;
    --section-padding: var(--space-2xl);
  }
  
  .nav__list {
    position: fixed;
    top: 0;
    right: -100%;
    width: 80%;
    max-width: 300px;
    height: 100vh;
    background-color: var(--color-bg);
    box-shadow: var(--shadow-xl);
    flex-direction: column;
    align-items: flex-start;
    padding: var(--space-4xl) var(--space-xl);
    gap: var(--space-lg);
    transition: right var(--transition-base);
  }
  
  .nav__list.active {
    right: 0;
  }
  
  .nav__toggle {
    display: flex;
  }
  
  .grid--2,
  .grid--3,
  .grid--4 {
    grid-template-columns: 1fr;
  }
  
  .hero-carousel {
    height: 500px;
  }
  
  .hero-carousel__title {
    font-size: var(--font-size-3xl);
  }
  
  .hero-carousel__description {
    font-size: var(--font-size-base);
  }
  
  .cta__buttons {
    flex-direction: column;
    align-items: stretch;
  }
}

/* Mobile (480px) */
@media (max-width: 480px) {
  :root {
    --font-size-3xl: 1.5rem;
    --font-size-4xl: 1.75rem;
    --font-size-5xl: 2rem;
    --container-padding: var(--space-md);
  }
  
  .hero-carousel {
    height: 400px;
  }
  
  .hero-carousel__nav {
    width: 40px;
    height: 40px;
    font-size: var(--font-size-xl);
  }
  
  .hero-carousel__nav--prev {
    left: var(--space-md);
  }
  
  .hero-carousel__nav--next {
    right: var(--space-md);
  }
  
  .btn {
    width: 100%;
  }
}

/* Large Desktop (1280px+) */
@media (min-width: 1280px) {
  .grid--3 {
    grid-template-columns: repeat(3, 1fr);
  }
  
  .grid--4 {
    grid-template-columns: repeat(4, 1fr);
  }
}

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

/* Skip to main content link */
.skip-link {
  position: absolute;
  top: -40px;
  left: 0;
  background: var(--color-primary);
  color: white;
  padding: var(--space-sm) var(--space-md);
  text-decoration: none;
  z-index: 100;
}

.skip-link:focus {
  top: 0;
}

/* Focus visible for keyboard navigation */
:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 2px;
}

/* Reduced motion for accessibility */
@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;
  }
}