* { margin: 0; padding: 0; box-sizing: border-box; }
body { font-family: 'Poppins', sans-serif; overflow-x: hidden; background-color: #fff; }

:root {
  --color-primary: #212b36;
  --color-accent: #3399FF;
  --color-footer: #212b36;
}

/* TOP BAR */
.top-bar {
  background-color: var(--color-primary);
  padding: 12px 0;
  font-size: 14px;
  border-bottom: 1px solid rgba(255,255,255,0.1);
}
.top-bar .container {
  max-width: 1400px;
  margin: 0 auto;
  padding: 0 20px;
}
.top-bar-left {
  display: flex;
  align-items: center;
  gap: 30px;
}
.top-bar-item {
  display: flex;
  align-items: center;
  gap: 8px;
  color: #f1f1f1;
}
.top-bar-item i {
  color: var(--color-accent);
  font-size: 14px;
}

/* NAV */
.main-nav {
  background-color: #ffffff;
  padding: 0;
  position: sticky;
  top: 0;
  z-index: 1000;
  box-shadow: 0 2px 10px rgba(0,0,0,0.05);
}
.nav-container {
  max-width: 1400px;
  margin: 0 auto;
  padding: 0 20px;
  display: flex;
  justify-content: flex-start;
  align-items: center;
  gap: 120px;
  height: 90px;
}
.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 15px 0;
}
.logo img {
  height: 50px;
  width: auto;
}
.nav-menu {
  display: flex;
  list-style: none;
  gap: 20px;
  align-items: center;
  margin: 0;
}
.nav-menu li {
  position: relative;
}
.nav-menu li a {
  color: var(--color-primary);
  text-decoration: none;
  padding: 25px 0;
  font-weight: 600;
  font-size: 15px;
  display: block;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  transition: color 0.3s;
}
.nav-menu li a:hover,
.nav-menu li a.active {
  color: var(--color-accent);
}
.dropdown-menu {
  position: absolute;
  top: 100%;
  left: 0;
  background: #fff;
  border-top: 3px solid var(--color-accent);
  box-shadow: 0 5px 15px rgba(0,0,0,0.1);
  min-width: 220px;
  display: none;
  z-index: 999;
  list-style: none;
  padding: 0;
}
.dropdown:hover .dropdown-menu {
  display: block;
  animation: fadeInUp 0.3s ease;
}
.dropdown-menu li a {
  color: #555 !important;
  padding: 12px 20px !important;
  border-bottom: 1px solid #f0f0f0;
}
.dropdown-menu li a:hover {
  background-color: #f8f9fa;
  color: var(--color-accent) !important;
}
.dropdown-menu li:last-child a {
  border-bottom: none;
}
@keyframes fadeInUp {
  from { opacity: 0; transform: translateY(10px); }
  to   { opacity: 1; transform: translateY(0); }
}
.mobile-menu-btn {
  display: none;
  color: var(--color-primary);
  font-size: 24px;
  cursor: pointer;
}

/* SAYFA BAŞLIĞI */
.page-header-section {
  background-color: var(--color-primary);
  padding: 60px 0;
  text-align: center;
  margin-bottom: 0;
  color: white;
}
.page-header-section h1 {
  font-size: 34px;
  font-weight: 600;
  color: white;
  margin: 0;
  letter-spacing: 0.5px;
  line-height: 1.4;
}

/* REFERANS GRID */
.container-ref {
  max-width: 1400px;
  margin: 0 auto;
  padding: 0 20px;
}
.ref-grid {
  display: grid;
  grid-template-columns: repeat(6, 1fr);
  justify-content: center;
  gap: 0;
  border-left: 1px solid #eee;
  border-top: 1px solid #eee;
  margin-top: 0;
  margin-bottom: 80px;
}
.ref-card {
  background: #fff;
  border-right: 1px solid #eee;
  border-bottom: 1px solid #eee;
  border-radius: 0;
  padding: 35px;
  aspect-ratio: 1 / 1;
  position: relative;
  overflow: hidden;
  display: flex;
  align-items: center;
  justify-content: center;
}
.ref-card:hover {
  z-index: 10;
  box-shadow: 0 0 30px rgba(0,0,0,0.15);
  border-color: transparent;
}
.ref-card img {
  width: 100%;
  height: 100%;
  object-fit: contain;
  filter: grayscale(100%);
  transition: all 0.3s ease;
  display: block;
  opacity: 0.7;
}
.ref-card:hover img {
  filter: grayscale(0%);
  opacity: 1;
  transform: none;
}

/* MOBİL */
@media (max-width: 1200px) {
  .ref-grid { grid-template-columns: repeat(4, 1fr); }
}
@media (max-width: 992px) {
  .ref-grid { grid-template-columns: repeat(3, 1fr); }
}
@media (max-width: 768px) {
  .ref-grid { grid-template-columns: repeat(2, 1fr); }
  .top-bar { display: none; }
  .main-nav { top: 0; }
  .mobile-menu-btn { display: block; }
  .nav-menu {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    width: 100%;
    background: #fff;
    flex-direction: column;
    padding: 20px;
    box-shadow: 0 5px 10px rgba(0,0,0,0.1);
  }
  .nav-menu.active { display: flex; }
  .search-input { display: none; }
  body { padding-top: 0; }
}

/* FOOTER */
.main-footer {
  background-color: var(--color-footer);
  color: #ddd;
  padding: 60px 0 0;
}
.footer-container {
  max-width: 1400px;
  margin: 0 auto;
  padding: 0 20px 40px;
  display: flex;
  flex-wrap: wrap;
  gap: 40px;
  justify-content: space-between;
}
.footer-col {
  flex: 1;
  min-width: 250px;
}
.footer-col h4 {
  color: white;
  font-size: 18px;
  margin-bottom: 25px;
  position: relative;
  padding-bottom: 10px;
}
.footer-col h4::after {
  content: '';
  position: absolute;
  left: 0;
  bottom: 0;
  width: 50px;
  height: 2px;
  background: var(--color-accent);
}
.footer-col .logo img {
  height: 50px;
  filter: none;
  margin-bottom: 20px;
}
.footer-col ul {
  list-style: none;
  padding: 0;
}
.footer-col ul li {
  margin-bottom: 12px;
}
.footer-col ul li a {
  color: #ddd;
  text-decoration: none;
  transition: color 0.3s;
  display: block;
}
.footer-col ul li a:hover {
  color: var(--color-accent);
  padding-left: 5px;
}
.footer-social-links {
  margin-top: 20px;
  display: flex;
  gap: 10px;
}
.footer-social-links a {
  display: inline-block;
  width: 35px;
  height: 35px;
  background: rgba(255,255,255,0.1);
  color: #fff;
  text-align: center;
  line-height: 35px;
  border-radius: 50%;
  transition: all 0.3s;
}
.footer-social-links a:hover {
  background: var(--color-accent);
}
.footer-bottom {
  background-color: #111;
  color: #888;
  padding: 20px 0;
  text-align: center;
  font-size: 14px;
  border-top: 1px solid rgba(255,255,255,0.05);
}