/* Cơ bản */
:root {
  --primary: #0056b3;
  --secondary: #004494;
  --bg-light: #f4f7f6;
  --text-dark: #333;
  --text-light: #fff;
}
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: 'Inter', sans-serif;
}
body { background: var(--bg-light); color: var(--text-dark); line-height: 1.6; }
a { text-decoration: none; color: inherit; }
ul { list-style: none; }
.container { width: 90%; max-width: 1200px; margin: auto; }

/* Header */
header {
  background: #fff;
  box-shadow: 0 2px 10px rgba(0,0,0,0.1);
  position: sticky; top: 0; z-index: 1000;
}
header .container { display: flex; justify-content: space-between; align-items: center; padding: 15px 0; }
.logo a { font-size: 24px; font-weight: bold; color: var(--primary); }
nav ul { display: flex; gap: 20px; }
nav a { font-weight: 500; font-size: 16px; padding: 5px 10px; transition: color 0.3s; }
nav a:hover, nav a.active { color: var(--primary); }

/* Hero Banner */
.hero {
  background: url('https://images.unsplash.com/photo-1486406146926-c627a92ad1ab?q=80&w=2070&auto=format&fit=crop') no-repeat center center/cover;
  height: 400px; display: flex; align-items: center; justify-content: center; color: #fff; text-align: center;
}
.hero h1 { font-size: 40px; margin-bottom: 10px; text-shadow: 2px 2px 5px rgba(0,0,0,0.5); }
.hero p { font-size: 18px; text-shadow: 1px 1px 3px rgba(0,0,0,0.5); }

/* 6 Grid Blocks */
.features-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(300px, 1fr)); gap: 20px; margin: 40px 0; }
.feature-card {
  background: #fff; border-radius: 8px; overflow: hidden; position: relative;
  box-shadow: 0 4px 6px rgba(0,0,0,0.05); transition: transform 0.3s;
}
.feature-card:hover { transform: translateY(-5px); }
.feature-card img { width: 100%; height: 200px; object-fit: cover; }
.feature-info { padding: 20px; }
.feature-info h3 { color: var(--primary); margin-bottom: 10px; }

/* Sections (Projects & News) */
.section-title { font-size: 24px; border-left: 5px solid var(--primary); padding-left: 10px; margin: 40px 0 20px; }
.grid-4 { display: grid; grid-template-columns: repeat(auto-fit, minmax(250px, 1fr)); gap: 20px; margin-bottom: 40px; border-bottom: 1px solid #ddd; padding-bottom: 40px; }
.card { background: #fff; border-radius: 8px; overflow: hidden; box-shadow: 0 2px 5px rgba(0,0,0,0.1); transition: 0.3s; }
.card:hover { transform: translateY(-5px); box-shadow: 0 5px 15px rgba(0,0,0,0.15); }
.card img { width: 100%; height: 160px; object-fit: cover; }
.card-content { padding: 15px; }
.card-content h4 { margin-bottom: 10px; color: var(--primary); font-size: 16px; }
.card-content p { font-size: 14px; color: #666; }

/* Footer */
footer { background: var(--secondary); color: #fff; padding: 40px 0; }
.footer-container { display: flex; justify-content: space-between; flex-wrap: wrap; gap: 20px; }
.footer-col { flex: 1; min-width: 250px; }
.footer-col h3 { margin-bottom: 20px; border-bottom: 2px solid var(--primary); padding-bottom: 10px; display: inline-block; }
.footer-col p, .footer-col li { margin-bottom: 10px; font-size: 14px; color: #ddd; }
.footer-col a { color: #ddd; transition: color 0.3s; }
.footer-col a:hover { color: #fff; }

/* Side Widgets */
.side-widgets { position: fixed; right: 0; top: 50%; transform: translateY(-50%); display: flex; flex-direction: column; gap: 10px; z-index: 1001; }
.widget { background: var(--primary); color: #fff; padding: 10px; border-radius: 5px 0 0 5px; cursor: pointer; transition: 0.3s; display: flex; align-items: center; justify-content: center; width: 40px; height: 40px; }
.widget i { font-size: 18px; }
.widget:hover { background: var(--secondary); width: 150px; justify-content: flex-start; padding-left: 15px; }
.widget span { display: none; margin-left: 10px; font-size: 14px; white-space: nowrap; }
.widget:hover span { display: inline-block; }

/* Subpage Settings */
.page-header { background: var(--primary); color: #fff; padding: 40px 0; text-align: center; }
.page-content { background: #fff; padding: 40px; border-radius: 8px; box-shadow: 0 2px 10px rgba(0,0,0,0.05); margin: 40px auto; max-width: 1000px; min-height: 400px; }