/* ==========================================================================
   SALT Bilgi Teknolojileri — Ana Sayfa
   Design system: bkz. YENIDEN-TASARIM-PLANI.md Bölüm 2
   ========================================================================== */

/* ---------- Reset ---------- */
*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body, h1, h2, h3, h4, p, figure { margin: 0; }
ul { margin: 0; padding: 0; list-style: none; }
img { display: block; max-width: 100%; }
a { color: inherit; text-decoration: none; }
button { font: inherit; color: inherit; background: none; border: 0; cursor: pointer; }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}

/* ---------- Design tokens ---------- */
:root {
  --bg-0: #0A1220;
  --bg-1: #0F1B2E;
  --surface: #14243C;
  --surface-hover: #1A2E4D;
  --border: rgba(122, 168, 220, 0.16);
  --border-strong: rgba(122, 168, 220, 0.32);

  --blue: #3AA3E3;
  --green: #2BB673;
  --gradient-brand: linear-gradient(135deg, #3AA3E3 0%, #2BB673 100%);

  --text-primary: #EDF3FA;
  --text-secondary: #9FB3C8;
  --text-on-brand: #06101C;

  --font-display: 'Space Grotesk', sans-serif;
  --font-body: 'Inter', sans-serif;

  --radius: 16px;
  --radius-lg: 24px;
  --section-pad: clamp(64px, 10vw, 120px);
  --container: 1160px;
}

body {
  background: var(--bg-0);
  color: var(--text-primary);
  font-family: var(--font-body);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

.container {
  width: 100%;
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 24px;
}

.eyebrow {
  display: block;
  font-family: var(--font-body);
  font-size: 0.8125rem;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--green);
  margin-bottom: 12px;
}

h1, h2, h3, h4 {
  font-family: var(--font-display);
  font-weight: 700;
  line-height: 1.2;
  color: var(--text-primary);
}

h2 { font-size: clamp(1.8rem, 3.5vw, 2.5rem); }
h3 { font-size: 1.25rem; font-weight: 600; }

.section-head {
  max-width: 640px;
  margin: 0 auto 56px;
  text-align: center;
}

.section-head p {
  color: var(--text-secondary);
  font-size: 1.0625rem;
  margin-top: 16px;
}

.gradient-text {
  background: var(--gradient-brand);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}

:focus-visible {
  outline: 2px solid var(--green);
  outline-offset: 3px;
  border-radius: 4px;
}

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 14px 28px;
  border-radius: 999px;
  font-weight: 600;
  font-size: 0.95rem;
  transition: transform 0.25s ease, box-shadow 0.25s ease, background 0.25s ease, border-color 0.25s ease;
  white-space: nowrap;
}

.btn-primary {
  background: var(--gradient-brand);
  color: var(--text-on-brand);
  box-shadow: 0 8px 24px rgba(58, 163, 227, 0.25);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 12px 32px rgba(58, 163, 227, 0.4);
}

.btn-secondary {
  background: transparent;
  color: var(--text-primary);
  border: 1px solid var(--border-strong);
}

.btn-secondary:hover {
  border-color: var(--blue);
  background: rgba(58, 163, 227, 0.08);
  transform: translateY(-2px);
}

.btn-small { padding: 10px 20px; font-size: 0.875rem; }

/* ==========================================================================
   Header
   ========================================================================== */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  padding: 20px 0;
  transition: background 0.3s ease, backdrop-filter 0.3s ease, border-color 0.3s ease, padding 0.3s ease;
  border-bottom: 1px solid transparent;
}

.site-header.scrolled {
  background: rgba(10, 18, 32, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom-color: var(--border);
  padding: 14px 0;
}

.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.logo img {
  height: 38px;
  width: auto;
  filter: brightness(1.12);
}

.main-nav {
  display: flex;
  align-items: center;
  gap: 36px;
}

.main-nav a {
  font-size: 0.9375rem;
  font-weight: 500;
  color: var(--text-secondary);
  transition: color 0.2s ease;
}

.main-nav a:hover { color: var(--text-primary); }

.header-actions {
  display: flex;
  align-items: center;
  gap: 20px;
}

.lang-switch {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 0.875rem;
  font-weight: 600;
}

.lang-switch a {
  color: var(--text-secondary);
  padding: 4px 2px;
}

.lang-switch a.active {
  color: var(--green);
}

.lang-switch span { color: var(--border-strong); }

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  padding: 8px;
}

.mobile-menu {
  display: none;
}

.nav-toggle span {
  width: 24px;
  height: 2px;
  background: var(--text-primary);
  border-radius: 2px;
  transition: transform 0.25s ease, opacity 0.25s ease;
}

.nav-toggle[aria-expanded="true"] span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
.nav-toggle[aria-expanded="true"] span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ==========================================================================
   Hero
   ========================================================================== */
.hero {
  position: relative;
  min-height: 92vh;
  display: flex;
  align-items: center;
  overflow: hidden;
  background: var(--bg-0);
}

.hero-canvas {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
}

.hero-fallback-bg {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: none;
}

.no-js .hero-fallback-bg,
.reduced-motion .hero-fallback-bg {
  display: block;
}

.no-js .hero-canvas,
.reduced-motion .hero-canvas {
  display: none;
}

.hero::after {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(ellipse 80% 60% at 20% 50%, rgba(10,18,32,0.35) 0%, rgba(10,18,32,0.92) 75%),
              linear-gradient(180deg, rgba(10,18,32,0.2) 0%, rgba(10,18,32,0.85) 100%);
  pointer-events: none;
}

.hero-content {
  position: relative;
  z-index: 2;
  max-width: 680px;
  padding-top: 100px;
}

.hero-content h1 {
  font-size: clamp(2.4rem, 5.5vw, 4rem);
  margin-bottom: 24px;
}

.hero-content h1 span {
  display: block;
  opacity: 0;
  transform: translateY(16px);
  animation: word-in 0.7s ease forwards;
}

.hero-content h1 span:nth-child(2) { animation-delay: 0.12s; }

@keyframes word-in {
  to { opacity: 1; transform: translateY(0); }
}

.hero-content .lead {
  font-size: 1.125rem;
  color: var(--text-secondary);
  max-width: 560px;
  margin-bottom: 36px;
}

.hero-cta {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
}

/* ==========================================================================
   Stats band
   ========================================================================== */
.stats {
  position: relative;
  z-index: 2;
  background: var(--bg-1);
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
  padding: 48px 0;
}

.stats .container {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
  text-align: center;
}

.stat-number {
  font-family: var(--font-display);
  font-size: clamp(2rem, 4vw, 2.75rem);
  font-weight: 700;
  background: var(--gradient-brand);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}

.stat-label {
  color: var(--text-secondary);
  font-size: 0.9375rem;
  margin-top: 6px;
}

/* ==========================================================================
   Reveal-on-scroll
   ========================================================================== */
.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.reveal.is-visible {
  opacity: 1;
  transform: translateY(0);
}

/* ==========================================================================
   Section base
   ========================================================================== */
section { position: relative; }

.section-pad {
  padding: var(--section-pad) 0;
}