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

:root {
  --primary-color: #007bff; /* A vibrant blue */
  --secondary-color: #6c757d; /* A muted grey */
  --accent-color: #28a745; /* A success green for CTAs */
  --background-light: #f8f9fa; /* Light background */
  --background-dark: #343a40; /* Dark background for footer */
  --text-color-dark: #212529; /* Dark text */
  --text-color-light: #f8f9fa; /* Light text for dark backgrounds */
  --font-family-sans: 'Noto Sans KR', sans-serif;
  --max-width: 1200px;
  --spacing-unit: 1rem; /* 16px */
}

body {
  font-family: var(--font-family-sans);
  line-height: 1.6;
  color: var(--text-color-dark);
  background-color: var(--background-light);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 calc(var(--spacing-unit) * 1.5); /* 24px */
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
  margin-bottom: var(--spacing-unit);
  font-weight: 700;
  color: var(--text-color-dark);
}

h1 {
  font-size: calc(var(--spacing-unit) * 2.5); /* 40px */
}

h2 {
  font-size: calc(var(--spacing-unit) * 2); /* 32px */
}

h3 {
  font-size: calc(var(--spacing-unit) * 1.75); /* 28px */
}

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

a {
  color: var(--primary-color);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

/* Header */
header {
  background-color: #ffffff;
  padding: calc(var(--spacing-unit) * 1) 0;
  border-bottom: 1px solid #e9ecef;
  box-shadow: 0 2px 4px rgba(0,0,0,0.05);
}

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

.logo {
  font-size: calc(var(--spacing-unit) * 1.75);
  margin: 0;
}

.logo a {
  color: var(--primary-color);
  font-weight: 700;
  text-decoration: none;
}

nav ul {
  list-style: none;
  display: flex;
  margin: 0;
}

nav ul li {
  margin-left: calc(var(--spacing-unit) * 1.5);
}

nav ul li a {
  color: var(--text-color-dark);
  font-weight: 400;
  padding: calc(var(--spacing-unit) * 0.5) 0;
  transition: color 0.3s ease;
}

nav ul li a:hover {
  color: var(--primary-color);
  text-decoration: none;
}

/* Hero Section */
.hero-section {
  background-image: linear-gradient(rgba(0, 0, 0, 0.6), rgba(0, 0, 0, 0.6)), url('/agentic_ai.png');
  background-size: cover;
  background-position: center;
  color: var(--text-color-light);
  text-align: center;
  padding: calc(var(--spacing-unit) * 6) 0; /* 96px */
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 60vh;
}

.hero-section h2 {
  color: var(--text-color-light);
  font-size: calc(var(--spacing-unit) * 3); /* 48px */
  margin-bottom: var(--spacing-unit);
}

.hero-section p {
  font-size: calc(var(--spacing-unit) * 1.25); /* 20px */
  margin-bottom: calc(var(--spacing-unit) * 2);
  opacity: 0.9;
}

.cta-button {
  display: inline-block;
  background-color: var(--accent-color);
  color: var(--text-color-light);
  padding: calc(var(--spacing-unit) * 0.75) calc(var(--spacing-unit) * 2);
  border-radius: 50px;
  text-decoration: none;
  font-weight: 700;
  transition: background-color 0.3s ease, transform 0.2s ease;
  border: none;
  cursor: pointer;
  font-size: var(--spacing-unit);
}

.cta-button:hover {
  background-color: #218838; /* Darker green */
  transform: translateY(-2px);
}

/* Sections General */
section {
  padding: calc(var(--spacing-unit) * 4) 0; /* 64px */
}

section:nth-of-type(even) {
  background-color: var(--background-light);
}

section h3 {
  text-align: center;
  margin-bottom: calc(var(--spacing-unit) * 3);
  position: relative;
  padding-bottom: var(--spacing-unit);
}

section h3::after {
  content: '';
  position: absolute;
  left: 50%;
  bottom: 0;
  transform: translateX(-50%);
  width: 60px;
  height: 4px;
  background-color: var(--primary-color);
  border-radius: 2px;
}

/* About Section */
.about-section p {
  max-width: 800px;
  margin: 0 auto var(--spacing-unit) auto;
  text-align: center;
}

/* Services Section */
.service-cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: calc(var(--spacing-unit) * 2);
  margin-top: calc(var(--spacing-unit) * 2);
}

.service-cards .card {
  background-color: #ffffff;
  padding: calc(var(--spacing-unit) * 2);
  border-radius: 8px;
  box-shadow: 0 4px 10px rgba(0,0,0,0.08);
  text-align: center;
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.service-cards .card:hover {
  transform: translateY(-5px);
  box-shadow: 0 6px 15px rgba(0,0,0,0.12);
}

.service-cards .card h4 {
  color: var(--primary-color);
  margin-bottom: var(--spacing-unit);
  font-size: calc(var(--spacing-unit) * 1.25);
}

/* Contact Section */
.contact-section form {
  max-width: 600px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: var(--spacing-unit);
}

.contact-section input[type="text"],
.contact-section input[type="email"],
.contact-section textarea {
  width: 100%;
  padding: calc(var(--spacing-unit) * 0.75);
  border: 1px solid #ced4da;
  border-radius: 5px;
  font-family: var(--font-family-sans);
  font-size: var(--spacing-unit);
}

.contact-section textarea {
  min-height: 120px;
  resize: vertical;
}

.contact-section button[type="submit"] {
  background-color: var(--primary-color);
  color: var(--text-color-light);
  padding: calc(var(--spacing-unit) * 0.75) calc(var(--spacing-unit) * 1.5);
  border: none;
  border-radius: 5px;
  cursor: pointer;
  font-size: var(--spacing-unit);
  font-weight: 700;
  transition: background-color 0.3s ease;
}

.contact-section button[type="submit"]:hover {
  background-color: #0056b3; /* Darker blue */
}


/* Footer */
footer {
  background-color: var(--background-dark);
  color: var(--text-color-light);
  text-align: center;
  padding: calc(var(--spacing-unit) * 2) 0;
  font-size: calc(var(--spacing-unit) * 0.875); /* 14px */
  margin-top: calc(var(--spacing-unit) * 4);
}

/* Responsive Design */
@media (max-width: 768px) {
  .hero-section {
    padding: calc(var(--spacing-unit) * 4) 0;
    min-height: 50vh;
  }

  .hero-section h2 {
    font-size: calc(var(--spacing-unit) * 2.25); /* 36px */
  }

  .hero-section p {
    font-size: var(--spacing-unit); /* 16px */
  }

  nav ul {
    flex-direction: column;
    margin-top: var(--spacing-unit);
    display: none; /* Hide nav for mobile, could add a hamburger menu */
  }

  header .container {
    flex-direction: column;
  }

  nav ul li {
    margin: var(--spacing-unit) 0;
  }

  .service-cards {
    grid-template-columns: 1fr;
  }

  section {
    padding: calc(var(--spacing-unit) * 2) 0;
  }
}

/* Small adjustments for mobile navigation display on toggle (if implemented) */
/* Example for a toggleable mobile nav */
/*
header.active nav ul {
  display: flex;
}
*/