/* ==========================================================================
   Base Styles & Reset
   ========================================================================== */

*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
  scroll-padding-top: var(--header-height);
  background-color: var(--bg-main);
  color: var(--text-primary);
  font-family: var(--font-body);
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
}

body {
  min-height: 100vh;
  overflow-x: hidden;
  background: var(--bg-main);
  color: var(--text-primary);
  line-height: 1.6;
  position: relative;
}

/* Engineering Blueprint Grid Background */
body::before {
  content: '';
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-image: 
    linear-gradient(to right, rgba(255, 255, 255, 0.018) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(255, 255, 255, 0.018) 1px, transparent 1px);
  background-size: 40px 40px;
  pointer-events: none;
  z-index: 0;
}

/* Ambient Radial Glows */
.ambient-glow {
  position: fixed;
  border-radius: 50%;
  filter: blur(120px);
  pointer-events: none;
  z-index: 0;
  opacity: 0.45;
  transition: opacity var(--transition-normal);
}

.ambient-glow-1 {
  top: -10%;
  right: -5%;
  width: 600px;
  height: 600px;
  background: radial-gradient(circle, rgba(54, 123, 151, 0.18) 0%, transparent 70%);
}

.ambient-glow-2 {
  top: 40%;
  left: -10%;
  width: 700px;
  height: 700px;
  background: radial-gradient(circle, rgba(14, 165, 233, 0.12) 0%, transparent 70%);
}

.ambient-glow-3 {
  bottom: 5%;
  right: 10%;
  width: 500px;
  height: 500px;
  background: radial-gradient(circle, rgba(54, 123, 151, 0.15) 0%, transparent 70%);
}

/* Custom Scrollbar */
::-webkit-scrollbar {
  width: 10px;
}

::-webkit-scrollbar-track {
  background: var(--bg-main);
}

::-webkit-scrollbar-thumb {
  background: #232736;
  border-radius: var(--radius-full);
  border: 2px solid var(--bg-main);
}

::-webkit-scrollbar-thumb:hover {
  background: var(--accent-gold);
}

/* Container & Sections */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 1.5rem;
  position: relative;
  z-index: 1;
}

.section {
  padding: 6.5rem 0;
  position: relative;
  z-index: 1;
}

.section-alt {
  background: linear-gradient(180deg, rgba(15, 17, 24, 0.6) 0%, rgba(9, 10, 15, 0.9) 100%);
  border-top: 1px solid var(--border-light);
  border-bottom: 1px solid var(--border-light);
}

/* Typography Hierarchy */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  color: var(--text-primary);
  font-weight: 700;
  line-height: 1.15;
  letter-spacing: -0.02em;
}

h1 {
  font-size: clamp(2.5rem, 5.5vw, 4.25rem);
}

h2 {
  font-size: clamp(2rem, 3.8vw, 3rem);
}

h3 {
  font-size: clamp(1.4rem, 2.2vw, 1.85rem);
}

h4 {
  font-size: 1.25rem;
}

p {
  color: var(--text-secondary);
  font-size: 1.05rem;
  line-height: 1.7;
}

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

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

ul {
  list-style: none;
}

button, input, textarea, select {
  font-family: inherit;
  font-size: 1rem;
}

/* Section Header Component */
.section-header {
  text-align: center;
  max-width: 780px;
  margin: 0 auto 4rem auto;
}

.section-tag {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.4rem 1rem;
  background: rgba(54, 123, 151, 0.1);
  border: 1px solid rgba(54, 123, 151, 0.3);
  border-radius: var(--radius-full);
  color: var(--accent-gold-light);
  font-size: 0.825rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: 1.25rem;
}

.section-tag svg {
  width: 14px;
  height: 14px;
  fill: currentColor;
}

.section-title {
  margin-bottom: 1.25rem;
}

.section-title .highlight {
  background: var(--grad-gold-metallic);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  display: inline-block;
}

.section-desc {
  font-size: 1.15rem;
  color: var(--text-muted);
}

/* Glass Surface Utility */
.glass-panel {
  background: var(--bg-card);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-md);
  transition: all var(--transition-normal);
}

.glass-panel:hover {
  border-color: var(--border-gold);
  box-shadow: var(--shadow-lg), 0 0 20px rgba(54, 123, 151, 0.12);
}