/*
 * Custom styles for the Bharti AI Tech landing page.
 * This stylesheet defines the overall layout, colours and responsive behaviour
 * without relying on external CSS frameworks. It includes CSS variables for
 * cohesive colour management, a responsive grid system and clean typography.
 */

/* CSS variables for colours */
:root {
  --primary: #4f46e5;      /* indigo */
  --primary-dark: #4338ca;
  --bg-light: #f9fafb;    /* light grey background */
  --bg-dark: #1f2937;     /* dark background for footer */
  --text-dark: #111827;   /* dark text */
  --text-medium: #374151; /* medium text */
  --text-light: #6b7280;  /* light text */
}

/* Global styles */
* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: 'Inter', sans-serif;
  color: var(--text-dark);
  line-height: 1.6;
  background-color: var(--bg-light);
  scroll-behavior: smooth;
}

h1, h2, h3 {
  margin: 0;
  font-weight: 600;
  line-height: 1.3;
}

p {
  margin-top: 0;
}

/* Container to centre content and limit width */
.container {
  width: 90%;
  max-width: 1200px;
  margin-left: auto;
  margin-right: auto;
}

/* Hero section */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  color: white;
  overflow: hidden;
}
.hero img {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
}
/* overlay using pseudo-element for gradient */
.hero::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, rgba(0,22,70,0.7), rgba(77,25,96,0.7), rgba(128,43,0,0.7));
  z-index: 1;
}
.hero .content {
  position: relative;
  z-index: 2;
  max-width: 600px;
  padding: 20px;
}
.hero h1 {
  font-size: 2.5rem;
  margin-bottom: 1rem;
}
.hero p {
  font-size: 1.25rem;
  color: #e5e7eb; /* light neutral for secondary text */
  margin-bottom: 2rem;
}
.hero .button {
  display: inline-block;
  padding: 0.875rem 2rem;
  background-color: var(--primary);
  color: white;
  border-radius: 999px;
  font-size: 1rem;
  font-weight: 600;
  text-decoration: none;
  transition: background-color 0.2s;
}
.hero .button:hover {
  background-color: var(--primary-dark);
}

/* Section base styles */
.section {
  padding: 4rem 0;
}
.section h2 {
  font-size: 2rem;
  text-align: center;
  margin-bottom: 2rem;
}

/* Services */
.services .cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1.5rem;
}
.service-card {
  background-color: white;
  padding: 2rem;
  border-radius: 1rem;
  box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
  text-align: center;
  transition: transform 0.2s, box-shadow 0.2s;
}
.service-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 8px 12px rgba(0, 0, 0, 0.15);
}
.service-card .icon {
  font-size: 2rem;
  color: var(--primary);
  margin-bottom: 1rem;
}
.service-card h3 {
  font-size: 1.25rem;
  margin-bottom: 0.5rem;
}
.service-card p {
  font-size: 0.95rem;
  color: var(--text-light);
}

/* Industries */
.industries .grid-wrapper {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1.5rem;
}
.industries ul {
  list-style-type: disc;
  padding-left: 1.25rem;
}
.industries ul li {
  margin-bottom: 0.5rem;
  font-size: 1rem;
  color: var(--text-medium);
}

/* Selected Work */
.work .projects {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1.5rem;
}
.work .project-card {
  overflow: hidden;
  border-radius: 1rem;
  box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}
.work .project-card img {
  display: block;
  width: 100%;
  height: 150px;
  object-fit: cover;
}

/* Process */
.process .steps {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1.5rem;
}
.process .step {
  text-align: center;
}
.process .number {
  font-size: 2rem;
  font-weight: bold;
  color: var(--primary);
  margin-bottom: 0.5rem;
}
.process h3 {
  font-size: 1.25rem;
  font-weight: 600;
  margin-bottom: 0.5rem;
}
.process p {
  font-size: 0.95rem;
  color: var(--text-light);
}

/* Contact */
.contact {
  text-align: center;
}
.contact h2 {
  margin-bottom: 0.5rem;
}
.contact p {
  max-width: 600px;
  margin: 0 auto 1.5rem;
  color: var(--text-medium);
}
.contact .button {
  display: inline-block;
  padding: 0.875rem 2rem;
  background-color: var(--primary);
  color: white;
  border-radius: 999px;
  font-weight: 600;
  text-decoration: none;
  transition: background-color 0.2s;
}
.contact .button:hover {
  background-color: var(--primary-dark);
}

/* Footer */
footer {
  background-color: var(--bg-dark);
  color: #d1d5db;
  text-align: center;
  padding: 2rem 0;
  font-size: 0.875rem;
}