/* =============================
   XJK Global Stylesheet (style.css)
   Dùng chung cho toàn site: home, sản phẩm, dịch vụ, v.v.
   ============================= */

:root {
  --color-bg: #ffffff;
  --color-text: #0d1b2a;
  --color-primary: #00c3ff;
  --color-accent: #0077b6;
  --color-card-bg: #f8fafc;
  --color-border: #e2e8f0;
  --shadow-card: 0 4px 10px rgba(0, 0, 0, 0.05);
}

body.dark {
  --color-bg: #0d1b2a;
  --color-text: #f8fafc;
  --color-primary: #00c3ff;
  --color-accent: #38bdf8;
  --color-card-bg: #1e293b;
  --color-border: #334155;
  --shadow-card: 0 4px 15px rgba(0, 0, 0, 0.4);
}

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

body {
  font-family: 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
  background-color: var(--color-bg);
  color: var(--color-text);
  line-height: 1.6;
  transition: background 0.3s, color 0.3s;
}

a {
  color: var(--color-accent);
  text-decoration: none;
  transition: color 0.2s;
}
a:hover {
  color: var(--color-primary);
}

.container {
  width: 90%;
  max-width: 1200px;
  margin: 0 auto;
}

/* ========== HEADER ========== */
.site-header {
  background: var(--color-card-bg);
  box-shadow: var(--shadow-card);
  position: sticky;
  top: 0;
  z-index: 1000;
}

.header-content {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1rem 0;
}

.logo {
  font-size: 1.5rem;
  font-weight: bold;
  color: var(--color-accent);
}
.logo span {
  color: var(--color-primary);
}

.main-nav a {
  margin: 0 1rem;
  font-weight: 500;
}

.theme-toggle {
  background: none;
  border: none;
  cursor: pointer;
  font-size: 1.2rem;
}

/* ========== HERO SECTION ========== */
.hero {
  background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
  color: #fff;
  text-align: center;
  padding: 6rem 1rem;
  border-radius: 0 0 3rem 3rem;
}

.hero h1 {
  font-size: 2.5rem;
  margin-bottom: 1rem;
}

.hero p {
  font-size: 1.1rem;
  margin-bottom: 2rem;
}

.btn-primary {
  background: #fff;
  color: var(--color-accent);
  padding: 0.75rem 1.5rem;
  border-radius: 0.5rem;
  font-weight: bold;
  transition: background 0.3s;
}
.btn-primary:hover {
  background: var(--color-primary);
  color: #fff;
}

/* ========== SERVICES ========== */
.services {
  padding: 4rem 0;
  text-align: center;
}

.services h2 {
  font-size: 2rem;
  margin-bottom: 2rem;
}

.grid-4 {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 1.5rem;
}

.card {
  background: var(--color-card-bg);
  border: 1px solid var(--color-border);
  border-radius: 1rem;
  padding: 2rem 1.5rem;
  box-shadow: var(--shadow-card);
  transition: transform 0.3s;
}

.card:hover {
  transform: translateY(-5px);
}

.card i {
  font-size: 2.5rem;
  color: var(--color-primary);
  margin-bottom: 1rem;
}

.card h3 {
  margin-bottom: 0.5rem;
}

/* ========== PROJECTS ========== */
.projects {
  padding: 4rem 0;
  background: var(--color-card-bg);
}

.projects h2 {
  text-align: center;
  font-size: 2rem;
  margin-bottom: 2rem;
}

.grid-3 {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 1.5rem;
}

.project-card {
  border-radius: 1rem;
  overflow: hidden;
  background: #fff;
  box-shadow: var(--shadow-card);
  text-align: center;
}

.project-card img {
  width: 100%;
  height: 200px;
  object-fit: cover;
}

.project-card h3 {
  padding: 1rem;
  color: var(--color-text);
}

/* ========== FOOTER ========== */
.site-footer {
  background: var(--color-accent);
  color: #fff;
  padding: 2rem 0;
}

.footer-content {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.footer-socials a {
  color: #fff;
  margin: 0 0.5rem;
  font-size: 1.3rem;
  transition: opacity 0.3s;
}
.footer-socials a:hover {
  opacity: 0.7;
}

/* ========== RESPONSIVE ========== */
@media (max-width: 768px) {
  .header-content {
    flex-direction: column;
  }
  .main-nav {
    margin-top: 0.5rem;
  }
  .hero h1 {
    font-size: 2rem;
  }
}