:root {
    --primary: #002347;
    --accent: #0073e6;
    --startup: #e67e22;
    --text: #2c3e50;
    --border: #eaeff2;
}

body {
    font-family: 'Segoe UI', sans-serif;
    background: #f0f2f5;
    margin: 0; padding: 40px 0;
    color: var(--text);
}

.container {
    max-width: 1100px;
    margin: 0 auto;
    background: #fff;
    box-shadow: 0 15px 50px rgba(0,0,0,0.1);
}

header {
    background: var(--primary);
    color: white;
    padding: 30px 40px 60px 40px; /* Điều chỉnh padding để cân đối */
}

/* Đưa nút vào góc phải phía trên trong Portfolio */
.header-top-row {
    display: flex;
    justify-content: flex-end; 
    margin-bottom: 0px;
}

.lang-selector {
    display: flex;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 20px;
    padding: 4px;
    border: 1px solid rgba(255, 255, 255, 0.1);
}

.lang-btn {
    display: flex;
    align-items: center;
    gap: 5px;
    padding: 5px 12px;
    cursor: pointer;
    border-radius: 15px;
    font-size: 12px;
    font-weight: bold;
    transition: 0.3s;
    opacity: 0.6;
    color: white;
}

.lang-btn img { width: 18px; height: 18px; }
.lang-btn.active { background: white; color: var(--primary); opacity: 1; }
.lang-btn:hover { opacity: 1; }

header h1 { margin: 0; font-size: 48px; letter-spacing: 2px; }
.headline { font-size: 22px; color: #8ebef0; margin: 10px 0; }
.meta-info { display: flex; gap: 30px; font-size: 14px; margin-top: 20px; opacity: 0.8; }

.main-layout { display: grid; grid-template-columns: 2.3fr 1fr; }
.timeline-column { padding: 40px; border-right: 1px solid var(--border); }
.sidebar { padding: 40px; background: #fafbfc; }

.section-heading {
    font-size: 18px;
    border-bottom: 2px solid var(--primary);
    padding-bottom: 10px;
    margin: 40px 0 25px 0;
    text-transform: uppercase;
}

/* Timeline Design */
.milestone {
    display: grid;
    grid-template-columns: 100px 1fr;
    gap: 20px;
    margin-bottom: 50px;
    position: relative;
}

.year { font-weight: 800; color: var(--accent); font-size: 14px; padding-top: 5px; }

.content {
    border-left: 2px solid var(--border);
    padding-left: 25px;
    position: relative;
}

.content::before {
    content: '';
    position: absolute;
    left: -7px; top: 8px;
    width: 12px; height: 12px;
    background: var(--accent);
    border-radius: 50%;
}

.content h3 { margin: 0; font-size: 20px; color: var(--primary); }
.company { font-weight: bold; margin: 5px 0; color: #636e72; font-size: 14px; }
.content ul { padding-left: 18px; font-size: 14px; margin: 15px 0; }

.highlight-box { background: #f8fbff; padding: 20px; border-radius: 8px; border: 1px solid #e1e9f1; }
.startup { border-left-color: var(--startup); }
.startup::before { background: var(--startup); }

.tech-bar {
    display: inline-block;
    background: #f1f4f6;
    padding: 6px 15px;
    border-radius: 4px;
    font-size: 12px;
    font-weight: bold;
    color: var(--primary);
}

.skill-tags { display: flex; flex-wrap: wrap; gap: 8px; }
.skill-tags span { background: var(--primary); color: white; padding: 5px 12px; border-radius: 4px; font-size: 12px; }
.info-item { margin-bottom: 15px; font-size: 14px; display: flex; align-items: center; gap: 10px; }
.info-item i { color: var(--accent); }
.edu-box { margin-bottom: 20px; font-size: 14px; }

@media (max-width: 900px) {
    .main-layout { grid-template-columns: 1fr; }
    .milestone { grid-template-columns: 1fr; gap: 5px; }
    .content { border-left: none; padding-left: 0; }
    .content::before { display: none; }
}