:root {
    --primary-color: #2c3e50;
    --secondary-color: #34495e;
    --accent-color: #3498db;
    --text-color: #333;
    --light-gray: #f4f4f4;
    --white: #ffffff;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: #e9ecef;
    margin: 0;
    padding: 20px;
}

.container {
    max-width: 900px;
    margin: 0 auto;
    background: var(--white);
    padding: 40px;
    box-shadow: 0 0 20px rgba(0,0,0,0.1);
    border-radius: 8px;
    position: relative;
}

/* Language Switcher */
.lang-switch {
    position: absolute;
    top: 20px;
    right: 20px;
    display: flex;
    gap: 5px;
}

.lang-btn {
    background: var(--white);
    border: 1px solid var(--accent-color);
    color: var(--accent-color);
    padding: 4px 8px;
    border-radius: 4px;
    cursor: pointer;
    font-size: 0.8em;
    font-weight: bold;
    transition: all 0.2s;
}

.lang-btn.active {
    background: var(--accent-color);
    color: var(--white);
}

/* Language Visibility */
:not(html)[lang="en"] {
    display: none !important;
}

html[lang="en"] :not(html)[lang="en"] {
    display: inline !important;
}

html[lang="en"] :not(html)[lang="vi"] {
    display: none !important;
}

/* Ensure block elements stay block when shown */
html[lang="en"] p[lang="en"],
html[lang="en"] div[lang="en"],
html[lang="en"] h2[lang="en"],
html[lang="en"] h3[lang="en"],
html[lang="en"] ul[lang="en"],
html[lang="en"] li[lang="en"],
html[lang="en"] section[lang="en"] {
    display: block !important;
}

html[lang="en"] .skills-grid[lang="en"] {
    display: grid !important;
}

html[lang="en"] .job-header[lang="en"] {
    display: flex !important;
}

header {
    text-align: center;
    border-bottom: 2px solid var(--accent-color);
    padding-bottom: 20px;
    margin-bottom: 30px;
}

header h1 {
    margin: 0;
    font-size: 2.5em;
    color: var(--primary-color);
}

.tagline {
    font-size: 1.2em;
    color: var(--secondary-color);
    font-weight: bold;
    margin: 10px 0;
}

.contact-info {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 20px;
    font-size: 0.9em;
}

.contact-info span {
    display: flex;
    align-items: center;
    gap: 5px;
}

.contact-info i {
    color: var(--accent-color);
}

h2 {
    color: var(--primary-color);
    border-left: 5px solid var(--accent-color);
    padding-left: 10px;
    margin-top: 30px;
    font-size: 1.5em;
}

h2 i {
    margin-right: 10px;
}

.about p {
    margin-bottom: 10px;
}

.job {
    margin-bottom: 25px;
}

.job-header {
    display: flex;
    justify-content: space-between;
    align-items: baseline;
}

.job-header h3 {
    margin: 0;
    color: var(--secondary-color);
}

.date {
    font-style: italic;
    color: #777;
    font-size: 0.9em;
}

.role {
    font-weight: bold;
    color: var(--accent-color);
    margin: 5px 0;
}

ul {
    padding-left: 20px;
}

.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
}

.skill-category h3 {
    font-size: 1.1em;
    margin-bottom: 10px;
    color: var(--secondary-color);
}

.skill-category p {
    font-size: 0.9em;
}

.edu-item h3 {
    margin: 0;
}

.languages p {
    margin: 5px 0;
}

/* Download CV Section */
.download-cv {
    text-align: center;
}

.download-buttons {
    display: flex;
    justify-content: center;
    gap: 20px;
    flex-wrap: wrap;
    margin-top: 15px;
}

.download-btn {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    padding: 12px 24px;
    background: var(--accent-color);
    color: var(--white);
    text-decoration: none;
    border-radius: 6px;
    font-weight: bold;
    font-size: 1em;
    transition: background 0.2s, transform 0.2s;
}

.download-btn:hover {
    background: var(--primary-color);
    transform: translateY(-2px);
}

.download-btn i {
    font-size: 1.2em;
}

@media (max-width: 600px) {
    .container {
        padding: 20px;
    }
    
    .job-header {
        flex-direction: column;
    }
    
    .contact-info {
        flex-direction: column;
        align-items: center;
    }
}