/* =====================================================
   Falling Cloud – Computer Systems Design
   Stylesheet: Clean, spacious, professional tech
   Colors: #1a1a2e text, #fafcff bg, #2D1B4E plum, #B4E83D lime
   Font: system-ui, -apple-system, sans-serif; 16px base
   ===================================================== */

/* ----- CSS Custom Properties ----- */
:root {
  --color-text: #1a1a2e;
  --color-bg: #fafcff;
  --color-accent: #2D1B4E;
  --color-highlight: #B4E83D;
  --color-light: #ffffff;
  --color-gray: #e0e4ec;
  --color-muted: #7a7a8a;

  --font-family: system-ui, -apple-system, sans-serif;
  --font-base: 16px;
  --line-height: 1.6;

  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 2rem;
  --spacing-xl: 4rem;

  --max-width: 1200px;
  --nav-height: 64px;
  --border-radius: 4px;
  --transition: 0.3s ease;
}

/* ----- Reset & Base ----- */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 100%; /* 16px default */
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-family);
  font-size: var(--font-base);
  line-height: var(--line-height);
  color: var(--color-text);
  background-color: var(--color-bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* ----- Typography ----- */
h1, h2, h3, h4, h5, h6 {
  font-weight: 600;
  line-height: 1.3;
  color: var(--color-text);
}

h1 { font-size: 2.5rem; }
h2 { font-size: 2rem; }
h3 { font-size: 1.5rem; }
h4 { font-size: 1.25rem; }

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

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

a:hover,
a:focus {
  color: var(--color-highlight);
}

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

/* ----- Container ----- */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--spacing-lg);
}

/* ----- Navigation (Fixed Top) ----- */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: var(--nav-height);
  background-color: var(--color-light);
  border-bottom: 1px solid var(--color-gray);
  z-index: 1000;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 var(--spacing-lg);
}

.nav__logo {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--color-text);
  letter-spacing: -0.02em;
}

.nav__logo span {
  color: var(--color-accent);
}

.nav__links {
  display: flex;
  gap: var(--spacing-lg);
  list-style: none;
}

.nav__links a {
  font-size: 0.9375rem;
  font-weight: 500;
  color: var(--color-text);
  padding: var(--spacing-sm) 0;
  border-bottom: 2px solid transparent;
  transition: border-color var(--transition), color var(--transition);
}

.nav__links a:hover,
.nav__links a:focus {
  border-bottom-color: var(--color-highlight);
  color: var(--color-accent);
}

/* Hamburger button (hidden by default) */
.nav__hamburger {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--spacing-xs);
  width: 32px;
  height: 24px;
  position: relative;
  flex-direction: column;
  justify-content: space-around;
}

.nav__hamburger span {
  display: block;
  width: 100%;
  height: 3px;
  background-color: var(--color-text);
  border-radius: 2px;
  transition: transform var(--transition), opacity var(--transition);
}

/* Hamburger animation for open state (JS toggle class 'active') */
.nav__hamburger.active span:nth-child(1) {
  transform: translateY(8px) rotate(45deg);
}

.nav__hamburger.active span:nth-child(2) {
  opacity: 0;
}

.nav__hamburger.active span:nth-child(3) {
  transform: translateY(-8px) rotate(-45deg);
}

/* ----- Hero Section ----- */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: calc(var(--nav-height) + var(--spacing-xl)) var(--spacing-lg) var(--spacing-xl);
  background-color: var(--color-light);
  border-bottom: 1px solid var(--color-gray);
}

.hero__content {
  max-width: 780px;
}

.hero__title {
  font-size: 3rem;
  margin-bottom: var(--spacing-md);
  color: var(--color-accent);
}

.hero__subtitle {
  font-size: 1.25rem;
  color: var(--color-muted);
  margin-bottom: var(--spacing-lg);
  line-height: 1.5;
}

.hero__cta {
  display: inline-block;
  background-color: var(--color-highlight);
  color: var(--color-text);
  font-weight: 600;
  padding: 0.75rem 2rem;
  border-radius: var(--border-radius);
  transition: background-color var(--transition), box-shadow var(--transition);
  border: none;
  cursor: pointer;
  font-size: 1rem;
}

.hero__cta:hover,
.hero__cta:focus {
  background-color: #a3d637;
  box-shadow: 0 4px 12px rgba(180, 232, 61, 0.4);
}

/* ----- General Sections ----- */
.section {
  padding: var(--spacing-xl) 0;
}

.section__header {
  text-align: center;
  margin-bottom: var(--spacing-xl);
}

.section__header h2 {
  margin-bottom: var(--spacing-sm);
}

.section__header p {
  max-width: 600px;
  margin: 0 auto;
  color: var(--color-muted);
}

/* ----- Cards (grid layout) ----- */
.cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--spacing-lg);
}

.card {
  background-color: var(--color-light);
  border: 1px solid var(--color-gray);
  border-radius: var(--border-radius);
  padding: var(--spacing-lg);
  transition: box-shadow var(--transition), border-color var(--transition);
}

.card:hover {
  box-shadow: 0 8px 24px rgba(45, 27, 78, 0.08);
  border-color: var(--color-accent);
}

.card__title {
  font-size: 1.125rem;
  font-weight: 600;
  margin-bottom: var(--spacing-sm);
  color: var(--color-accent);
}

.card__description {
  font-size: 0.9375rem;
  color: var(--color-text);
  line-height: 1.6;
}

/* ----- Contact Form ----- */
.contact-form {
  max-width: 640px;
  margin: 0 auto;
  background-color: var(--color-light);
  padding: var(--spacing-lg);
  border: 1px solid var(--color-gray);
  border-radius: var(--border-radius);
}

.contact-form .form-group {
  margin-bottom: var(--spacing-md);
}

.contact-form label {
  display: block;
  font-weight: 500;
  margin-bottom: var(--spacing-xs);
  font-size: 0.875rem;
  color: var(--color-text);
}

.contact-form input,
.contact-form textarea {
  width: 100%;
  padding: 0.75rem;
  border: 1px solid var(--color-gray);
  border-radius: var(--border-radius);
  font-family: var(--font-family);
  font-size: 1rem;
  background-color: var(--color-bg);
  color: var(--color-text);
  transition: border-color var(--transition), box-shadow var(--transition);
}

.contact-form input:focus,
.contact-form textarea:focus {
  outline: none;
  border-color: var(--color-accent);
  box-shadow: 0 0 0 3px rgba(45, 27, 78, 0.1);
}

.contact-form textarea {
  min-height: 140px;
  resize: vertical;
}

.contact-form button {
  display: inline-block;
  background-color: var(--color-accent);
  color: var(--color-light);
  font-weight: 600;
  padding: 0.75rem 2rem;
  border: none;
  border-radius: var(--border-radius);
  cursor: pointer;
  transition: background-color var(--transition), box-shadow var(--transition);
  font-size: 1rem;
}

.contact-form button:hover,
.contact-form button:focus {
  background-color: #3d226a;
  box-shadow: 0 4px 12px rgba(45, 27, 78, 0.3);
}

/* ----- Footer ----- */
.footer {
  background-color: var(--color-text);
  color: var(--color-light);
  padding: var(--spacing-lg) 0;
  border-top: 3px solid var(--color-accent);
}

.footer__inner {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: center;
  gap: var(--spacing-md);
}

.footer__brand {
  font-size: 1.125rem;
  font-weight: 700;
}

.footer__brand span {
  color: var(--color-highlight);
}

.footer__links {
  display: flex;
  gap: var(--spacing-lg);
  list-style: none;
}

.footer__links a {
  color: var(--color-gray);
  font-size: 0.875rem;
  transition: color var(--transition);
}

.footer__links a:hover,
.footer__links a:focus {
  color: var(--color-highlight);
}

.footer__copy {
  font-size: 0.8125rem;
  color: var(--color-muted);
  width: 100%;
  text-align: center;
  margin-top: var(--spacing-md);
  padding-top: var(--spacing-md);
  border-top: 1px solid rgba(250, 252, 255, 0.1);
}

/* ----- Responsive ----- */
/* Mobile first – adjust breakpoints as needed */

/* Small screens: up to 768px */
@media (max-width: 768px) {
  .nav__hamburger {
    display: flex; /* show hamburger */
  }

  .nav__links {
    position: absolute;
    top: var(--nav-height);
    left: 0;
    width: 100%;
    background-color: var(--color-light);
    flex-direction: column;
    align-items: center;
    gap: 0;
    padding: var(--spacing-md) 0;
    border-bottom: 1px solid var(--color-gray);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.05);
    transform: scaleY(0);
    transform-origin: top;
    transition: transform var(--transition);
    pointer-events: none;
  }

  .nav__links.active {
    transform: scaleY(1);
    pointer-events: auto;
  }

  .nav__links li {
    width: 100%;
    text-align: center;
  }

  .nav__links a {
    display: block;
    padding: var(--spacing-md) var(--spacing-lg);
    border-bottom: none;
  }

  .nav__links a:hover,
  .nav__links a:focus {
    background-color: var(--color-bg);
    border-bottom: none;
  }

  .hero__title {
    font-size: 2.25rem;
  }

  .hero__subtitle {
    font-size: 1.125rem;
  }

  .container {
    padding: 0 var(--spacing-md);
  }

  .footer__inner {
    flex-direction: column;
    text-align: center;
  }

  .footer__links {
    flex-wrap: wrap;
    justify-content: center;
  }
}

/* Extra small: up to 480px */
@media (max-width: 480px) {
  .hero__title {
    font-size: 1.875rem;
  }

  .card {
    padding: var(--spacing-md);
  }

  .contact-form {
    padding: var(--spacing-md);
  }
}

/* Larger screens: minimal adjustments */
@media (min-width: 769px) {
  .nav__hamburger {
    display: none;
  }
}

/* ----- Utility helper (for JS toggling) ----- */
.no-scroll {
  overflow: hidden;
}