:root { --blue: #0056b3; --text: #333; --bg: #f4f7f6; --white: #ffffff; --gray: #f8f9fa; }
body { font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif; background: var(--bg); color: var(--text); margin: 0; line-height: 1.6; }
header { background: white; padding: 25px 0; text-align: center; border-bottom: 1px solid #ddd; }
.logo { font-size: 2.5rem; font-weight: 900; color: var(--text); text-decoration: none; letter-spacing: -2px; }
.logo span { color: var(--blue); }
nav { background: white; border-bottom: 4px solid var(--blue); position: sticky; top: 0; z-index: 100; text-align: center; }
nav ul { list-style: none; padding: 0; margin: 0; display: flex; justify-content: center; flex-wrap: wrap; }
nav li a { display: block; padding: 15px 20px; text-decoration: none; color: #555; font-weight: bold; text-transform: uppercase; font-size: 0.85rem; transition: 0.3s; }
nav li a:hover, nav li a.active { color: var(--blue); background: #f0f0f0; }
.wrapper { max-width: 1100px; margin: 20px auto; display: grid; grid-template-columns: 1fr 320px; gap: 30px; padding: 0 20px; }
.article-card { background: white; border-radius: 12px; overflow: hidden; margin-bottom: 40px; box-shadow: 0 4px 15px rgba(0,0,0,0.05); }
.article-img { width: 100%; height: 350px; object-fit: cover; background: #eee; }
.article-body { padding: 30px; }
.cat-tag { background: var(--blue); color: white; padding: 5px 12px; font-size: 0.75rem; font-weight: bold; text-transform: uppercase; border-radius: 4px; }
h1 { font-size: 2.8rem; margin-bottom: 10px; color: #111; }
h2 { font-size: 2rem; margin: 15px 0; color: #111; line-height: 1.2; }
.box-grey { background: var(--gray); border-left: 5px solid #ccc; padding: 20px; margin: 20px 0; border-radius: 0 8px 8px 0; }
.tip-box { background: #e7f3ff; border: 1px solid #b3d7ff; padding: 20px; border-radius: 8px; color: #004085; font-weight: 500; margin-top: 20px; }
.btn-more { display: inline-block; margin-top: 20px; padding: 12px 25px; background: var(--blue); color: white; text-decoration: none; border-radius: 6px; font-weight: bold; }
footer { background: #222; color: #ccc; text-align: center; padding: 50px 20px; margin-top: 60px; }
.sidebar { position: sticky; top: 100px; height: fit-content; }
@media (max-width: 900px) { .wrapper { grid-template-columns: 1fr; } .sidebar { display: none; } }