/* --- VARIABLES & RESET --- */
:root {
    --primary-color: #0056b3; /* Xanh đậm doanh nghiệp */
    --secondary-color: #00a8e8; /* Xanh sáng điểm nhấn */
    --bg-light: #ffffff;
    --bg-gray: #f8f9fa;
    --text-dark: #212529;
    --text-gray: #6c757d;
    --card-shadow: 0 4px 6px rgba(0,0,0,0.05);
    --card-hover: 0 10px 15px rgba(0,0,0,0.1);
}

* { margin: 0; padding: 0; box-sizing: border-box; font-family: 'Segoe UI', Roboto, Helvetica, Arial, sans-serif; }
body { background-color: var(--bg-light); color: var(--text-dark); line-height: 1.6; }
a { text-decoration: none; color: inherit; transition: 0.3s; }
ul { list-style: none; }

.container { max-width: 1200px; margin: 0 auto; padding: 0 20px; }
.btn { display: inline-block; padding: 10px 25px; border-radius: 5px; font-weight: 600; cursor: pointer; }
.btn-primary { background: var(--primary-color); color: #fff; border: 2px solid var(--primary-color); }
.btn-primary:hover { background: #004494; border-color: #004494; }
.btn-outline { background: transparent; color: var(--primary-color); border: 2px solid var(--primary-color); margin-left: 10px; }
.btn-outline:hover { background: var(--primary-color); color: #fff; }

/* --- NAVBAR --- */
.navbar { background: #fff; box-shadow: 0 2px 10px rgba(0,0,0,0.05); position: sticky; top: 0; z-index: 1000; }
.nav-container { display: flex; justify-content: space-between; align-items: center; height: 70px; }
.logo { font-size: 1.5rem; font-weight: 800; color: var(--primary-color); letter-spacing: 1px; }
.nav-links { display: flex; gap: 30px; }
.nav-links a { font-weight: 500; color: var(--text-dark); }
.nav-links a:hover { color: var(--secondary-color); }
.btn-contact { padding: 8px 20px; background: var(--text-dark); color: #fff !important; border-radius: 4px; }

/* --- HERO SECTION --- */
.hero { padding: 100px 0; background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%); text-align: center; }
.badge { background: #e3f2fd; color: var(--primary-color); padding: 5px 15px; border-radius: 20px; font-size: 0.9rem; font-weight: 600; display: inline-block; margin-bottom: 15px; }
.hero h1 { font-size: 3rem; margin-bottom: 20px; color: var(--text-dark); line-height: 1.2; }
.hero p { max-width: 700px; margin: 0 auto 30px; color: var(--text-gray); font-size: 1.1rem; }

/* --- SECTIONS COMMON --- */
.section-light { padding: 80px 0; background: #fff; }
.section-gray { padding: 80px 0; background: var(--bg-gray); }
.section-title { text-align: center; font-size: 2rem; margin-bottom: 50px; position: relative; padding-bottom: 15px; }
.section-title::after { content: ''; position: absolute; bottom: 0; left: 50%; transform: translateX(-50%); width: 60px; height: 3px; background: var(--secondary-color); }

/* --- SKILLS GRID --- */
.skills-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(250px, 1fr)); gap: 30px; }
.skill-card { background: #fff; padding: 30px; border-radius: 10px; box-shadow: var(--card-shadow); border: 1px solid #eee; transition: 0.3s; }
.skill-card:hover { transform: translateY(-5px); box-shadow: var(--card-hover); border-color: var(--secondary-color); }
.icon-box { font-size: 2rem; color: var(--secondary-color); margin-bottom: 20px; }
.skill-card h3 { margin-bottom: 15px; font-size: 1.2rem; }
.skill-list li { margin-bottom: 10px; font-size: 0.95rem; color: var(--text-gray); border-bottom: 1px dashed #eee; padding-bottom: 5px; }
.skill-list strong { color: var(--text-dark); }

/* --- PROJECT GRID --- */
.project-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(320px, 1fr)); gap: 30px; }
.project-card { background: #fff; border-radius: 10px; overflow: hidden; box-shadow: var(--card-shadow); transition: 0.3s; display: flex; flex-direction: column; }
.project-card:hover { transform: translateY(-5px); box-shadow: var(--card-hover); }
.card-img { height: 180px; background: #343a40; color: #fff; display: flex; align-items: center; justify-content: center; font-size: 1.5rem; font-weight: bold; letter-spacing: 2px; }
.card-body { padding: 25px; flex-grow: 1; display: flex; flex-direction: column; }
.card-body h3 { margin-bottom: 10px; color: var(--primary-color); }
.desc { color: var(--text-gray); font-size: 0.95rem; margin-bottom: 20px; flex-grow: 1; }
.tech-stack { display: flex; flex-wrap: wrap; gap: 8px; }
.tech-stack span { background: #e9ecef; color: #495057; padding: 4px 10px; border-radius: 4px; font-size: 0.8rem; font-weight: 500; }

/* --- FOOTER --- */
footer { background: #1a1a1a; color: #fff; padding: 50px 0 20px; }
.footer-content { display: flex; justify-content: space-between; align-items: center; flex-wrap: wrap; border-bottom: 1px solid #333; padding-bottom: 30px; margin-bottom: 20px; }
.footer-left h3 { color: var(--secondary-color); margin-bottom: 5px; }
.footer-social a { color: #aaa; margin-left: 20px; font-size: 1rem; }
.footer-social a:hover { color: #fff; }
.footer-bottom { text-align: center; color: #555; font-size: 0.9rem; }

/* Mobile Responsive */
@media (max-width: 768px) {
    .hero h1 { font-size: 2rem; }
    .nav-links { display: none; } /* Đơn giản hóa cho mobile demo */
    .footer-content { flex-direction: column; text-align: center; gap: 20px; }
    .footer-social a { margin: 0 10px; }
}
/* Đa ngôn ngữ */
.en {
    display: none;
}

.lang-en .en {
    display: inline;
}

.lang-en .vi {
    display: none;
}

/* Đảm bảo các đoạn mô tả dài vẫn giữ đúng định dạng block */
p span.vi, p span.en {
    display: block;
}