/* ===================== ROOT ===================== */
:root {
  --primary: #4f46e5;
  --secondary: #06b6d4;
  --bg: #f8fafc;
  --card-bg: #ffffff;
  --text: #0f172a;
  --muted: #64748b;
  --radius: 16px;
  --shadow: 0 10px 30px rgba(0,0,0,0.08);
  --transition: all .3s ease;
}

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

body {
  font-family: "Inter", system-ui, sans-serif;
  background: linear-gradient(180deg,#f8fafc,#eef2ff);
  color: var(--text);
  line-height: 1.6;
}

/* ===================== CONTAINER ===================== */
.container {
  width: 100%;
  max-width: 1150px;
  margin: auto;
  padding: 0 20px;
}

/* ===================== HEADER ===================== */
.site-header {
  background: rgba(255,255,255,.85);
  backdrop-filter: blur(12px);
  position: sticky;
  top: 0;
  z-index: 100;
  border-bottom: 1px solid #e5e7eb;
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 70px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
}

.logo {
  width: 42px;
  height: 42px;
  border-radius: 50%;
}

.brand-text {
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--primary);
}

/* ===================== NAV ===================== */
.main-nav {
  display: flex;
  gap: 28px;
}

.main-nav a {
  text-decoration: none;
  color: var(--muted);
  font-weight: 500;
  position: relative;
  transition: var(--transition);
}

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

.main-nav a::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -6px;
  width: 0;
  height: 2px;
  background: linear-gradient(90deg,var(--primary),var(--secondary));
  transition: .3s;
}

.main-nav a:hover::after,
.main-nav a.active::after {
  width: 100%;
}

.mobile-toggle {
  display: none;
  font-size: 1.6rem;
  background: none;
  border: none;
  cursor: pointer;
}

/* ===================== ABOUT PAGE ===================== */
.about-page {
  padding: 80px 0;
}

.about-page h1 {
  text-align: center;
  font-size: 2.6rem;
  margin-bottom: 60px;
  background: linear-gradient(90deg,var(--primary),var(--secondary));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.about-cards {
  display: grid;
  grid-template-columns: repeat(auto-fit,minmax(260px,1fr));
  gap: 30px;
}

.card {
  background: var(--card-bg);
  padding: 32px;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  transition: var(--transition);
  position: relative;
  overflow: hidden;
}

.card::before {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(120deg,transparent,var(--secondary),transparent);
  opacity: .08;
}

.card:hover {
  transform: translateY(-10px);
  box-shadow: 0 20px 40px rgba(0,0,0,.12);
}

.card h2 {
  margin-bottom: 14px;
  font-size: 1.4rem;
  color: var(--primary);
}

.card p {
  color: var(--muted);
  font-size: .96rem;
}

/* ===================== MOBILE ===================== */
@media (max-width: 768px) {
  .main-nav {
    position: absolute;
    top: 70px;
    left: 0;
    width: 100%;
    background: white;
    flex-direction: column;
    padding: 20px;
    display: none;
    box-shadow: var(--shadow);
  }

  .main-nav.active {
    display: flex;
  }

  .mobile-toggle {
    display: block;
  }

  .about-page h1 {
    font-size: 2.1rem;
  }
}