/* ======================================
   S&Y Corp. ICT 융합 연구팀 — 공통 스타일
   ====================================== */

:root {
  --primary: #5B4FCF;
  --primary-light: #7B6FE8;
  --primary-dark: #3d34a5;
  --primary-bg: #f0eeff;
  --accent: #8B5CF6;
  --text-main: #1a1a2e;
  --text-sub: #4a4a6a;
  --text-muted: #888;
  --bg-white: #ffffff;
  --bg-light: #f8f9fc;
  --bg-section: #f4f3fc;
  --border: #e2e0f0;
  --shadow: 0 4px 24px rgba(91,79,207,0.09);
  --shadow-hover: 0 8px 36px rgba(91,79,207,0.18);
  --radius: 14px;
  --radius-sm: 8px;
  --font: 'Pretendard', 'Noto Sans KR', 'Apple SD Gothic Neo', sans-serif;
}

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

html {
  scroll-behavior: smooth;
}

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

a {
  text-decoration: none;
  color: inherit;
}

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

ul, ol {
  list-style: none;
}

/* ——— Header / Nav ——— */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: rgba(255,255,255,0.97);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
  height: 68px;
  display: flex;
  align-items: center;
}

.header-inner {
  width: 100%;
  max-width: 1180px;
  margin: 0 auto;
  padding: 0 32px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.logo-wrap {
  display: flex;
  align-items: center;
  gap: 12px;
}

.logo-icon {
  width: 40px;
  height: 40px;
  background: linear-gradient(135deg, var(--primary), var(--accent));
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-weight: 800;
  font-size: 16px;
  letter-spacing: -0.5px;
}

.logo-text {
  display: flex;
  flex-direction: column;
}

.logo-name {
  font-size: 15px;
  font-weight: 800;
  color: var(--primary);
  letter-spacing: -0.3px;
  line-height: 1.2;
}

.logo-sub {
  font-size: 10.5px;
  color: var(--text-muted);
  font-weight: 500;
  letter-spacing: 0.2px;
  line-height: 1.3;
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 4px;
}

.nav-link {
  padding: 6px 14px;
  border-radius: 20px;
  font-size: 14px;
  font-weight: 600;
  color: var(--text-sub);
  transition: all 0.2s;
  white-space: nowrap;
}

.nav-link:hover,
.nav-link.active {
  color: var(--primary);
  background: var(--primary-bg);
}

.nav-link.active {
  text-decoration: underline;
  text-underline-offset: 3px;
}

.hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
  padding: 4px;
}

.hamburger span {
  width: 24px;
  height: 2px;
  background: var(--text-main);
  border-radius: 2px;
  transition: all 0.3s;
}

/* ——— Mobile Menu ——— */
.mobile-menu {
  display: none;
  position: fixed;
  top: 68px;
  left: 0;
  right: 0;
  background: #fff;
  border-bottom: 1px solid var(--border);
  padding: 16px 24px;
  z-index: 999;
  flex-direction: column;
  gap: 4px;
  box-shadow: 0 8px 24px rgba(0,0,0,0.07);
}

.mobile-menu.open {
  display: flex;
}

.mobile-menu .nav-link {
  padding: 10px 16px;
  border-radius: var(--radius-sm);
}

/* ——— Page Body ——— */
.page-body {
  padding-top: 68px;
}

/* ——— Section Layout ——— */
.section {
  padding: 90px 0;
}

.section-inner {
  max-width: 1180px;
  margin: 0 auto;
  padding: 0 32px;
}

.section-label {
  display: inline-block;
  padding: 4px 14px;
  background: var(--primary-bg);
  color: var(--primary);
  border-radius: 20px;
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 1.2px;
  text-transform: uppercase;
  margin-bottom: 14px;
}

.section-title {
  font-size: clamp(26px, 3vw, 36px);
  font-weight: 800;
  color: var(--text-main);
  letter-spacing: -0.5px;
  line-height: 1.3;
  margin-bottom: 16px;
}

.section-title em {
  color: var(--primary);
  font-style: normal;
}

.section-desc {
  font-size: 16px;
  color: var(--text-sub);
  max-width: 680px;
  line-height: 1.75;
}

/* ——— Buttons ——— */
.btn-primary {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 13px 28px;
  background: var(--primary);
  color: #fff;
  border-radius: 30px;
  font-size: 14.5px;
  font-weight: 700;
  transition: all 0.25s;
  border: none;
  cursor: pointer;
}

.btn-primary:hover {
  background: var(--primary-dark);
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(91,79,207,0.35);
}

.btn-outline {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 13px 28px;
  background: transparent;
  color: var(--primary);
  border: 2px solid var(--primary);
  border-radius: 30px;
  font-size: 14.5px;
  font-weight: 700;
  transition: all 0.25s;
  cursor: pointer;
}

.btn-outline:hover {
  background: var(--primary);
  color: #fff;
  transform: translateY(-2px);
}

/* ——— Cards ——— */
.card {
  background: var(--bg-white);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px;
  transition: all 0.3s;
}

.card:hover {
  box-shadow: var(--shadow-hover);
  transform: translateY(-4px);
  border-color: var(--primary-light);
}

.card-icon {
  width: 52px;
  height: 52px;
  border-radius: 12px;
  background: var(--primary-bg);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 22px;
  margin-bottom: 16px;
}

/* ——— Grid ——— */
.grid-2 { display: grid; grid-template-columns: repeat(2, 1fr); gap: 24px; }
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
.grid-4 { display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px; }

/* ——— Footer ——— */
.site-footer {
  background: #12111e;
  color: #ccc;
  padding: 56px 0 32px;
}

.footer-inner {
  max-width: 1180px;
  margin: 0 auto;
  padding: 0 32px;
}

.footer-top {
  display: grid;
  grid-template-columns: 1.6fr 1fr 1fr;
  gap: 48px;
  padding-bottom: 40px;
  border-bottom: 1px solid #2a2840;
}

.footer-brand .logo-name {
  color: #fff;
  font-size: 17px;
}

.footer-brand .logo-sub {
  color: #888;
}

.footer-brand p {
  margin-top: 12px;
  font-size: 13.5px;
  color: #888;
  line-height: 1.8;
}

.footer-col h4 {
  font-size: 13px;
  font-weight: 700;
  color: #fff;
  letter-spacing: 1px;
  text-transform: uppercase;
  margin-bottom: 16px;
}

.footer-col ul li {
  margin-bottom: 8px;
}

.footer-col ul li a {
  font-size: 13.5px;
  color: #888;
  transition: color 0.2s;
}

.footer-col ul li a:hover {
  color: var(--primary-light);
}

.footer-bottom {
  padding-top: 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 12.5px;
  color: #555;
  flex-wrap: wrap;
  gap: 8px;
}

/* ——— Fade-in ——— */
.fade-in {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.fade-in.visible {
  opacity: 1;
  transform: none;
}

/* ——— Responsive ——— */
@media (max-width: 900px) {
  .site-nav { display: none; }
  .hamburger { display: flex; }
  .grid-3 { grid-template-columns: repeat(2, 1fr); }
  .grid-4 { grid-template-columns: repeat(2, 1fr); }
  .footer-top { grid-template-columns: 1fr; gap: 32px; }
}

@media (max-width: 600px) {
  .section { padding: 64px 0; }
  .section-inner { padding: 0 20px; }
  .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; }
  .header-inner { padding: 0 20px; }
}