/* ============================================================
 *  Zeppelin Computing — Global Stylesheet
 *  ============================================================
 *  Color palette:
 *    --bg-primary    : Deep navy          (#0a0f1a)
 *    --bg-secondary  : Slightly lighter    (#111827)
 *    --bg-card       : Card surfaces       (#1a2236)
 *    --accent        : Electric blue        (#3b82f6)
 *    --accent-hover  : Brighter blue        (#60a5fa)
 *    --text-primary  : Near-white           (#e5e7eb)
 *    --text-secondary: Muted gray           (#9ca3af)
 *    --border        : Subtle border        (#1f2937)
 *
 *  Typography:
 *    Headings : "DM Sans" — geometric, modern, highly readable
 *    Body     : "IBM Plex Sans" — technical heritage, clean reading
 *  ============================================================ */

/* --- CSS Custom Properties (edit these to re-theme the whole site) --- */
:root {
  --bg-primary: #0a0f1a;
  --bg-secondary: #111827;
  --bg-card: #1a2236;
  --accent: #3b82f6;
  --accent-hover: #60a5fa;
  --text-primary: #e5e7eb;
  --text-secondary: #9ca3af;
  --border: #1f2937;
  --max-width: 1100px;
  --radius: 8px;
  --transition: 0.25s ease;
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: "IBM Plex Sans", sans-serif;
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.7;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  -webkit-font-smoothing: antialiased;
}

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

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

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

/* --- Typography --- */
h1, h2, h3, h4 {
  font-family: "DM Sans", sans-serif;
  font-weight: 700;
  line-height: 1.2;
  color: #ffffff;
}

h1 { font-size: 2.75rem; }
h2 { font-size: 2rem; margin-bottom: 1rem; }
h3 { font-size: 1.35rem; margin-bottom: 0.5rem; }

p {
  color: var(--text-secondary);
  max-width: 65ch; /* keeps paragraphs comfortable to read */
}

/* --- Layout Utility --- */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
}

.section {
  padding: 5rem 0;
}

/* ============================================================
 *  HEADER / NAVIGATION
 *  ============================================================ */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background-color: rgba(10, 15, 26, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  /*
   *   This creates a clipping region that extends far below the header.
   *   The mobile nav menu (z-index: 90) is positioned behind this header
   *   (z-index: 100), so as it slides down from behind the header bar,
   *   it only becomes visible once it clears the bottom edge.
   *
   *   The 9999px bottom value just means "extend clipping far enough
   *   to never cut off the menu once it's fully open."
   */
  clip-path: inset(0 0 -9999px 0);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 4rem;
}

/* --- Logo --- */
.logo {
  font-family: "DM Sans", sans-serif;
  font-size: 1.25rem;
  font-weight: 700;
  color: #ffffff;
  letter-spacing: -0.02em;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.logo .accent {
  color: var(--accent);
}

/* --- Desktop Navigation --- */
.nav-links {
  display: flex;
  list-style: none;
  gap: 2rem;
}

.nav-links a {
  color: var(--text-secondary);
  font-size: 0.9rem;
  font-weight: 500;
  letter-spacing: 0.02em;
  transition: color var(--transition);
}

.nav-links a:hover,
.nav-links a.active {
  color: #ffffff;
}

/* --- Hamburger Button (hidden on desktop) --- */
.menu-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.25rem;
}

.menu-toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--text-primary);
  margin: 5px 0;
  border-radius: 2px;
  transition: var(--transition);
}

/* --- Mobile Navigation --- */
@media (max-width: 768px) {
  .menu-toggle {
    display: block;
  }

  .nav-links {
    /*
     *     On mobile the nav is positioned directly below the header
     *     and clips behind it using overflow on the body/header.
     *
     *     We start with NO transition — this prevents the brief
     *     "closing" flash on page load. The .nav-ready class is
     *     added by main.js after a short delay, which enables the
     *     smooth slide animation only AFTER the page has settled.
     *
     *     visibility: hidden ensures screen readers and keyboard
     *     navigation can't reach it while it's closed.
     */
    position: fixed;
    top: 4rem;
    left: 0;
    right: 0;
    z-index: 90;
    flex-direction: column;
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border);
    padding: 1.5rem;
    gap: 1rem;
    transform: translateY(-200%);
    visibility: hidden;
    /* No transition by default — prevents flash on load */
  }

  /* Transition is only enabled after JS adds this class */
  .nav-links.nav-ready {
    transition: transform 0.3s ease, visibility 0.3s ease;
  }

  .nav-links.open {
    transform: translateY(0);
    visibility: visible;
  }
}

/* ============================================================
 *  HERO SECTION  (index.html)
 *  ============================================================ */
.hero {
  padding: 8rem 0 6rem;
  text-align: center;
  position: relative;
}

/*
 * Subtle grid-dot background texture.
 * Created with a tiny radial-gradient — no image files needed.
 */
.hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image: radial-gradient(circle, rgba(59,130,246,0.08) 1px, transparent 1px);
  background-size: 28px 28px;
  pointer-events: none;
}

.hero h1 {
  margin-bottom: 1.25rem;
  position: relative;
}

.hero p {
  font-size: 1.15rem;
  max-width: 540px;
  margin: 0 auto 2.5rem;
}

/* --- Call-to-action buttons --- */
.cta-group {
  display: flex;
  gap: 1rem;
  justify-content: center;
  flex-wrap: wrap;
  position: relative;
}

.btn {
  display: inline-block;
  padding: 0.75rem 1.75rem;
  border-radius: var(--radius);
  font-family: "DM Sans", sans-serif;
  font-weight: 600;
  font-size: 0.95rem;
  transition: all var(--transition);
  cursor: pointer;
  border: none;
}

.btn-primary {
  background-color: var(--accent);
  color: #ffffff;
}

.btn-primary:hover {
  background-color: var(--accent-hover);
  color: #ffffff;
}

.btn-outline {
  border: 1.5px solid var(--border);
  color: var(--text-primary);
  background: transparent;
}

.btn-outline:hover {
  border-color: var(--accent);
  color: var(--accent);
}

/* ============================================================
 *  CARD GRID  (used on index for service previews, etc.)
 *  ============================================================ */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1.5rem;
}

.card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 2rem;
  transition: border-color var(--transition), transform var(--transition);
}

.card:hover {
  border-color: var(--accent);
  transform: translateY(-3px);
}

.card-icon {
  font-size: 1.75rem;
  margin-bottom: 1rem;
}

.card p {
  font-size: 0.95rem;
}

/* ============================================================
 *  PAGE-SPECIFIC CONTENT SECTIONS
 *  ============================================================ */
.page-intro {
  padding: 5rem 0 3rem;
  text-align: center;
}

.page-intro p {
  margin: 0.75rem auto 0;
  max-width: 560px;
  font-size: 1.05rem;
}

/* --- About page: simple two-column layout --- */
.about-content {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 3rem;
  align-items: start;
}

@media (max-width: 768px) {
  .about-content {
    grid-template-columns: 1fr;
  }
}

/* --- Contact Info Block --- */
.contact-block {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 2.5rem;
  max-width: 500px;
  margin: 0 auto;
}

.contact-block p {
  margin-bottom: 1rem;
}

.contact-block .email-link {
  font-size: 1.2rem;
  font-weight: 600;
}

/* ============================================================
 *  FOOTER
 *  ============================================================ */
.site-footer {
  margin-top: auto; /* pushes footer to bottom of the viewport */
  border-top: 1px solid var(--border);
  padding: 2rem 0;
  text-align: center;
}

.site-footer p {
  font-size: 0.85rem;
  color: var(--text-secondary);
  margin: 0 auto;
}

.footer-links {
  list-style: none;
  display: flex;
  justify-content: center;
  gap: 1.5rem;
  margin-bottom: 0.75rem;
}

.footer-links a {
  font-size: 0.85rem;
  color: var(--text-secondary);
}

.footer-links a:hover {
  color: #ffffff;
}

/* ============================================================
 *  BLOG LISTING  (blog/index.html)
 *  ============================================================ */
.blog-list {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

/*
 * Blog cards are styled as full-width clickable blocks.
 * The entire <a> tag is the card, so the whole thing is clickable.
 */
.blog-card {
  display: block;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.75rem 2rem;
  text-decoration: none;
  transition: border-color var(--transition), transform var(--transition);
}

.blog-card:hover {
  border-color: var(--accent);
  transform: translateY(-2px);
}

.blog-card-date {
  display: block;
  font-size: 0.8rem;
  color: var(--text-secondary);
  margin-bottom: 0.35rem;
  letter-spacing: 0.03em;
}

.blog-card h3 {
  color: #ffffff;
  margin-bottom: 0.4rem;
}

.blog-card p {
  font-size: 0.95rem;
  color: var(--text-secondary);
  margin-bottom: 0.75rem;
}

.blog-card-read {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--accent);
}

/* ============================================================
 *  BLOG POST  (blog/posts/*.html)
 *  ============================================================ */
 .blog-post {
   max-width: 720px;
   margin: 0 auto;
 }

 .blog-back-link {
   display: inline-block;
   font-size: 0.85rem;
   color: var(--text-secondary);
   margin-bottom: 1.5rem;
   transition: color var(--transition);
 }

 .blog-back-link:hover {
   color: var(--accent);
 }

 .blog-post-date {
   display: block;
   font-size: 0.85rem;
   color: var(--text-secondary);
   margin-bottom: 0.5rem;
   letter-spacing: 0.03em;
 }

 .blog-post h1 {
   font-size: 2.25rem;
   margin-bottom: 2rem;
 }

 /* Paragraphs and headings within blog post body */
 .blog-post p {
   margin-bottom: 1.25rem;
   max-width: none; /* override the global 65ch cap inside posts */
 }

 .blog-post h2 {
   margin-top: 2.5rem;
   margin-bottom: 0.75rem;
 }

 .blog-post h3 {
   margin-top: 2rem;
   margin-bottom: 0.5rem;
 }

 /* Inline code */
 .blog-post code {
   background: rgba(59, 130, 246, 0.1);
   color: var(--accent-hover);
   padding: 0.15em 0.4em;
   border-radius: 4px;
   font-size: 0.9em;
 }

 /* Code blocks */
 .blog-post pre {
   background: var(--bg-secondary);
   border: 1px solid var(--border);
   border-radius: var(--radius);
   padding: 1.25rem;
   overflow-x: auto;
   margin-bottom: 1.5rem;
 }

 .blog-post pre code {
   background: none;
   padding: 0;
   font-size: 0.85rem;
   color: var(--text-primary);
 }

 /* Block quotes */
 .blog-post blockquote {
   border-left: 3px solid var(--accent);
   padding-left: 1.25rem;
   margin: 1.5rem 0;
   color: var(--text-secondary);
   font-style: italic;
 }

 /* Lists inside blog posts */
 .blog-post ul,
.blog-post ol {
  margin: 1rem 0 1.5rem 1.25rem;
  color: var(--text-secondary);
}

.blog-post li {
  margin-bottom: 0.4rem;
}

@media (max-width: 768px) {
  .blog-post h1 { font-size: 1.75rem; }
}

/* ============================================================
 *  FADE-IN ANIMATION
 *  Elements with class "fade-in" will gently appear on load.
 *  Applied via a tiny Intersection Observer in main.js.
 *  ============================================================ */
.fade-in {
  opacity: 0;
  transform: translateY(16px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ============================================================
 *  RESPONSIVE FINE-TUNING
 *  ============================================================ */
@media (max-width: 768px) {
  h1 { font-size: 2rem; }
  h2 { font-size: 1.5rem; }
  .hero { padding: 5rem 0 4rem; }
  .section { padding: 3.5rem 0; }
}