/* ==========================================================================
   CSS DESIGN SYSTEM FOR HO HAI SON'S WEB CV
   ========================================================================== */

/* --- Color Tokens & Variables --- */
:root {
    /* Dark Theme (Default) */
    --bg-primary: #0b0f19;
    --bg-secondary: #111827;
    --bg-card: rgba(17, 24, 39, 0.7);
    --bg-card-hover: rgba(31, 41, 55, 0.8);
    --text-primary: #f3f4f6;
    --text-secondary: #9ca3af;
    --text-muted: #6b7280;
    
    --accent-cyan: #06b6d4;
    --accent-cyan-glow: rgba(6, 182, 212, 0.15);
    --accent-orange: #f97316;
    --accent-orange-glow: rgba(249, 115, 22, 0.15);
    
    --border-color: rgba(255, 255, 255, 0.08);
    --border-hover: rgba(6, 182, 212, 0.3);
    --shadow-color: rgba(0, 0, 0, 0.4);
    --shadow-glow: 0 8px 32px 0 rgba(0, 0, 0, 0.3);
    
    --badge-bg: rgba(6, 182, 212, 0.1);
    --badge-text: #22d3ee;
    --btn-secondary-bg: rgba(255, 255, 255, 0.05);
    --btn-secondary-hover: rgba(255, 255, 255, 0.1);
    
    --transition-speed: 0.3s;
    --border-radius-lg: 16px;
    --border-radius-md: 10px;
    --border-radius-sm: 6px;
}

/* Light Theme Variables */
body.light-theme {
    --bg-primary: #f8fafc;
    --bg-secondary: #f1f5f9;
    --bg-card: rgba(255, 255, 255, 0.8);
    --bg-card-hover: rgba(255, 255, 255, 0.95);
    --text-primary: #0f172a;
    --text-secondary: #475569;
    --text-muted: #64748b;
    
    --accent-cyan: #0891b2;
    --accent-cyan-glow: rgba(8, 145, 178, 0.1);
    --accent-orange: #ea580c;
    --accent-orange-glow: rgba(234, 88, 12, 0.1);
    
    --border-color: rgba(15, 23, 42, 0.08);
    --border-hover: rgba(8, 145, 178, 0.4);
    --shadow-color: rgba(15, 23, 42, 0.05);
    --shadow-glow: 0 8px 30px rgba(0, 0, 0, 0.03);
    
    --badge-bg: rgba(8, 145, 178, 0.08);
    --badge-text: #0891b2;
    --btn-secondary-bg: rgba(15, 23, 42, 0.04);
    --btn-secondary-hover: rgba(15, 23, 42, 0.08);
}

/* --- Base & Reset Styles --- */
* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    transition: background-color var(--transition-speed) ease, color var(--transition-speed) ease;
    overflow-x: hidden;
}

h1, h2, h3, h4, h5, h6 {
    font-family: 'Montserrat', sans-serif;
    font-weight: 700;
    letter-spacing: -0.02em;
    margin-bottom: 0.5rem;
}

a {
    color: var(--accent-cyan);
    text-decoration: none;
    transition: color var(--transition-speed) ease;
}

a:hover {
    color: var(--accent-orange);
}

ul {
    list-style: none;
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1.5rem;
}

/* --- Reusable Components --- */
.badge {
    display: inline-block;
    padding: 0.35rem 0.85rem;
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    background-color: var(--badge-bg);
    color: var(--badge-text);
    border-radius: 50px;
    border: 1px solid rgba(6, 182, 212, 0.15);
    margin-bottom: 1rem;
    box-shadow: 0 2px 10px rgba(6, 182, 212, 0.05);
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.75rem 1.75rem;
    font-size: 0.9rem;
    font-weight: 600;
    border-radius: var(--border-radius-md);
    cursor: pointer;
    border: none;
    transition: all var(--transition-speed) cubic-bezier(0.4, 0, 0.2, 1);
    font-family: 'Inter', sans-serif;
}

.btn-primary {
    background: linear-gradient(135deg, var(--accent-cyan), #0891b2);
    color: #ffffff;
    box-shadow: 0 4px 15px rgba(6, 182, 212, 0.3);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(6, 182, 212, 0.5);
    background: linear-gradient(135deg, #0891b2, var(--accent-cyan));
}

.btn-secondary {
    background-color: var(--btn-secondary-bg);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}

.btn-secondary:hover {
    background-color: var(--btn-secondary-hover);
    border-color: var(--accent-cyan);
    transform: translateY(-2px);
}

.btn-block {
    display: flex;
    width: 100%;
}

/* Section Headers */
.section-header {
    text-align: center;
    margin-bottom: 3.5rem;
}

.section-title {
    font-size: 2.25rem;
    position: relative;
    display: inline-block;
    padding-bottom: 0.75rem;
    margin-bottom: 0.75rem;
    background: linear-gradient(120deg, var(--text-primary) 60%, var(--accent-cyan));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 60px;
    height: 3px;
    background: linear-gradient(90deg, var(--accent-cyan), var(--accent-orange));
    border-radius: 50px;
}

.section-subtitle {
    font-size: 1rem;
    color: var(--text-secondary);
    max-width: 600px;
    margin: 0 auto;
}

/* --- Header & Navigation --- */
#navbar {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 1000;
    background-color: var(--bg-card);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border-color);
    transition: all var(--transition-speed) ease;
}

.nav-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 70px;
}

.logo {
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--text-primary);
    font-family: 'Montserrat', sans-serif;
    letter-spacing: -0.03em;
}

.logo-accent {
    background: linear-gradient(135deg, var(--accent-cyan), var(--accent-orange));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.nav-links {
    display: flex;
    gap: 2rem;
}

.nav-links a {
    color: var(--text-secondary);
    font-size: 0.95rem;
    font-weight: 500;
    position: relative;
    padding: 0.25rem 0;
}

.nav-links a:hover,
.nav-links a.active {
    color: var(--text-primary);
}

.nav-links a::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background-color: var(--accent-cyan);
    transition: width var(--transition-speed) ease;
}

.nav-links a:hover::after,
.nav-links a.active::after {
    width: 100%;
}

.nav-actions {
    display: flex;
    align-items: center;
    gap: 1rem;
}

#theme-toggle {
    background: none;
    border: 1px solid var(--border-color);
    color: var(--text-primary);
    width: 40px;
    height: 40px;
    border-radius: var(--border-radius-md);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-speed) ease;
    font-size: 1.1rem;
}

#theme-toggle:hover {
    border-color: var(--accent-cyan);
    color: var(--accent-cyan);
    background-color: var(--btn-secondary-hover);
}

.mobile-menu-toggle {
    display: none;
    background: none;
    border: none;
    color: var(--text-primary);
    font-size: 1.5rem;
    cursor: pointer;
}

/* --- Hero Section --- */
.hero-section {
    padding: 140px 0 80px 0;
    position: relative;
}

/* Glow decoration background */
.hero-section::before {
    content: '';
    position: absolute;
    top: 10%;
    left: -100px;
    width: 300px;
    height: 300px;
    background: radial-gradient(circle, var(--accent-cyan-glow) 0%, transparent 70%);
    z-index: -1;
    pointer-events: none;
}

.hero-container {
    display: grid;
    grid-template-columns: 1.2fr 0.8fr;
    gap: 4rem;
    align-items: center;
}

.hero-content {
    animation: fadeInUp 0.8s ease;
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 800;
    line-height: 1.1;
    margin-bottom: 0.75rem;
    background: linear-gradient(135deg, #ffffff 50%, #9ca3af);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

body.light-theme .hero-title {
    background: linear-gradient(135deg, #0f172a 50%, #475569);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.hero-subtitle {
    font-size: 1.25rem;
    font-weight: 500;
    color: var(--accent-cyan);
    margin-bottom: 1.5rem;
    display: flex;
    align-items: center;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.hero-subtitle .divider {
    color: var(--text-muted);
}

.hero-bio {
    color: var(--text-secondary);
    font-size: 1.05rem;
    margin-bottom: 2rem;
    text-align: justify;
}

.hero-contact-quick {
    display: flex;
    flex-wrap: wrap;
    gap: 1.5rem;
    margin-bottom: 2.5rem;
    font-size: 0.9rem;
    color: var(--text-secondary);
}

.hero-contact-quick span {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.hero-contact-quick i {
    color: var(--accent-cyan);
}

.hero-actions {
    display: flex;
    gap: 1.25rem;
    flex-wrap: wrap;
}

.hero-image-area {
    position: relative;
    display: flex;
    justify-content: center;
    align-items: center;
    animation: fadeIn 1.2s ease;
}

.avatar-container {
    width: 320px;
    height: 320px;
    border-radius: 50%;
    overflow: hidden;
    border: 4px solid var(--bg-primary);
    box-shadow: var(--shadow-glow);
    z-index: 2;
    position: relative;
    transition: transform 0.5s ease;
}

.avatar-container:hover {
    transform: scale(1.02);
}

.avatar-image {
    width: 100%;
    height: 100%;
    object-fit: cover;
    object-position: center 20%;
}

.image-glow-ring {
    position: absolute;
    width: 340px;
    height: 340px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--accent-cyan), var(--accent-orange));
    z-index: 1;
    animation: rotateGlow 8s linear infinite;
    opacity: 0.8;
}

/* --- Stats Section --- */
.stats-section {
    padding: 40px 0;
    position: relative;
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 2rem;
}

.stat-card {
    background-color: var(--bg-card);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border: 1px solid var(--border-color);
    padding: 2rem 1.75rem;
    border-radius: var(--border-radius-lg);
    text-align: center;
    transition: all var(--transition-speed) ease;
    position: relative;
    overflow: hidden;
}

.stat-card:hover {
    transform: translateY(-5px);
    border-color: var(--border-hover);
    box-shadow: 0 10px 30px rgba(6, 182, 212, 0.08);
}

.stat-icon {
    font-size: 2.25rem;
    color: var(--accent-cyan);
    margin-bottom: 0.75rem;
    height: 50px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.stat-number {
    display: inline-block;
    font-size: 3rem;
    font-weight: 800;
    font-family: 'Montserrat', sans-serif;
    color: var(--text-primary);
    line-height: 1;
}

.stat-suffix {
    display: inline-block;
    font-size: 2rem;
    font-weight: 700;
    color: var(--accent-orange);
    font-family: 'Montserrat', sans-serif;
}

.stat-title {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text-primary);
    margin: 0.5rem 0 0.25rem 0;
}

.stat-desc {
    font-size: 0.85rem;
    color: var(--text-secondary);
}

/* --- Experience Section --- */
.experience-section {
    padding: 80px 0;
}

.timeline {
    position: relative;
    max-width: 900px;
    margin: 0 auto;
    padding-left: 2rem;
}

.timeline::before {
    content: '';
    position: absolute;
    top: 0;
    left: 7px;
    width: 2px;
    height: 100%;
    background-color: var(--border-color);
}

.timeline-item {
    position: relative;
    margin-bottom: 3.5rem;
}

.timeline-item:last-child {
    margin-bottom: 0;
}

.timeline-dot {
    position: absolute;
    top: 8px;
    left: -29px;
    width: 16px;
    height: 16px;
    border-radius: 50%;
    background-color: var(--accent-cyan);
    border: 4px solid var(--bg-primary);
    box-shadow: 0 0 10px var(--accent-cyan);
    transition: all var(--transition-speed) ease;
    z-index: 2;
}

.timeline-item:hover .timeline-dot {
    background-color: var(--accent-orange);
    box-shadow: 0 0 12px var(--accent-orange);
}

.timeline-date {
    font-size: 0.85rem;
    font-weight: 600;
    text-transform: uppercase;
    color: var(--accent-orange);
    letter-spacing: 0.05em;
    margin-bottom: 0.5rem;
}

.timeline-content {
    background-color: var(--bg-card);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border: 1px solid var(--border-color);
    padding: 2.25rem;
    border-radius: var(--border-radius-lg);
    box-shadow: var(--shadow-glow);
    transition: all var(--transition-speed) ease;
}

.timeline-content:hover {
    border-color: var(--border-hover);
    transform: translateX(5px);
}

.job-title {
    font-size: 1.4rem;
    font-weight: 700;
    color: var(--text-primary);
}

.job-company {
    font-size: 0.95rem;
    font-weight: 500;
    color: var(--accent-cyan);
    margin-bottom: 1.25rem;
}

.job-highlights {
    display: flex;
    gap: 1.5rem;
    flex-wrap: wrap;
    background-color: rgba(255, 255, 255, 0.02);
    border: 1px solid var(--border-color);
    padding: 0.75rem 1.25rem;
    border-radius: var(--border-radius-md);
    margin-bottom: 1.5rem;
}

body.light-theme .job-highlights {
    background-color: rgba(15, 23, 42, 0.02);
}

.highlight-item {
    display: flex;
    flex-direction: column;
}

.highlight-label {
    font-size: 0.75rem;
    color: var(--text-muted);
    text-transform: uppercase;
}

.highlight-value {
    font-size: 1.05rem;
    font-weight: 700;
    color: var(--accent-cyan);
    font-family: 'Montserrat', sans-serif;
}

.job-badge {
    display: inline-flex;
    align-items: center;
    gap: 0.4rem;
    background-color: rgba(239, 68, 68, 0.1);
    color: #ef4444;
    border: 1px solid rgba(239, 68, 68, 0.15);
    padding: 0.25rem 0.75rem;
    font-size: 0.8rem;
    font-weight: 600;
    border-radius: var(--border-radius-sm);
    margin-bottom: 1.25rem;
}

.job-details {
    padding-left: 1.25rem;
    list-style-type: square;
}

.job-details li {
    color: var(--text-secondary);
    margin-bottom: 0.75rem;
    font-size: 0.95rem;
    line-height: 1.5;
}

.job-details li:last-child {
    margin-bottom: 0;
}

.job-details strong {
    color: var(--text-primary);
}

/* --- Equipment & Portfolio Section --- */
.equipment-section {
    padding: 80px 0;
    position: relative;
}

.portfolio-promo {
    background: linear-gradient(135deg, var(--bg-card) 0%, rgba(6, 182, 212, 0.05) 100%);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius-lg);
    padding: 2.5rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 3.5rem;
    position: relative;
    overflow: hidden;
}

.portfolio-promo::after {
    content: '';
    position: absolute;
    right: -50px;
    bottom: -50px;
    width: 200px;
    height: 200px;
    background: radial-gradient(circle, var(--accent-cyan-glow) 0%, transparent 70%);
    z-index: 1;
}

.promo-text {
    z-index: 2;
}

.promo-text h3 {
    font-size: 1.6rem;
    margin-bottom: 0.5rem;
}

.promo-text p {
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
    max-width: 600px;
}

.promo-link {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 1.2rem;
    font-weight: 700;
    color: var(--accent-cyan);
    font-family: 'Montserrat', sans-serif;
    border-bottom: 2px solid transparent;
    padding-bottom: 0.25rem;
}

.promo-link:hover {
    color: var(--accent-orange);
    border-bottom-color: var(--accent-orange);
}

.promo-icon {
    font-size: 5rem;
    color: rgba(6, 182, 212, 0.1);
    z-index: 2;
}

.subsection-title {
    font-size: 1.4rem;
    margin-bottom: 1.75rem;
    color: var(--text-primary);
}

.equipment-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 2rem;
    margin-bottom: 3rem;
}

.equipment-card {
    background-color: var(--bg-card);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius-lg);
    padding: 1.75rem;
    transition: all var(--transition-speed) ease;
}

.equipment-card:hover {
    border-color: var(--border-hover);
    transform: translateY(-5px);
    box-shadow: var(--shadow-glow);
}

.equip-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
}

.equip-category {
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    color: var(--accent-orange);
    letter-spacing: 0.05em;
}

.equip-header i {
    font-size: 1.5rem;
    color: var(--accent-cyan);
}

.equip-name {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
}

.equip-status {
    font-size: 0.85rem;
    color: var(--text-secondary);
    display: flex;
    align-items: center;
    gap: 0.4rem;
    margin-bottom: 1rem;
}

.status-dot {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    display: inline-block;
}

.status-dot.owned {
    background-color: #10b981;
    box-shadow: 0 0 8px #10b981;
}

.status-dot.experienced {
    background-color: var(--accent-cyan);
    box-shadow: 0 0 8px var(--accent-cyan);
}

.equip-desc {
    font-size: 0.9rem;
    color: var(--text-secondary);
    line-height: 1.5;
}

.equipment-footer {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    background-color: var(--bg-card);
    border: 1px solid var(--border-color);
    padding: 1.5rem;
    border-radius: var(--border-radius-lg);
}

.tech-tag {
    font-size: 0.95rem;
    color: var(--text-secondary);
}

.tech-tag strong {
    color: var(--text-primary);
}

/* --- Skills Section --- */
.skills-section {
    padding: 80px 0;
}

.skills-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 2rem;
}

.skill-card {
    background-color: var(--bg-card);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius-lg);
    padding: 2rem 1.75rem;
    transition: all var(--transition-speed) ease;
}

.skill-card:hover {
    border-color: var(--border-hover);
    transform: translateY(-5px);
    box-shadow: var(--shadow-glow);
}

.skill-icon {
    font-size: 2rem;
    color: var(--accent-cyan);
    margin-bottom: 1rem;
}

.skill-card h3 {
    font-size: 1.25rem;
    margin-bottom: 0.75rem;
}

.skill-desc {
    font-size: 0.9rem;
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
    line-height: 1.5;
    height: 70px; /* Cố định chiều cao mô tả để giữ các thẻ đều nhau */
    overflow: hidden;
    text-overflow: ellipsis;
}

.skill-level {
    width: 100%;
    height: 6px;
    background-color: rgba(255, 255, 255, 0.05);
    border-radius: 10px;
    overflow: hidden;
    position: relative;
}

body.light-theme .skill-level {
    background-color: rgba(15, 23, 42, 0.05);
}

.skill-level span {
    position: absolute;
    top: 0;
    left: 0;
    height: 100%;
    border-radius: 10px;
    background: linear-gradient(90deg, var(--accent-cyan), var(--accent-orange));
    transition: width 1.5s ease-out;
}

/* --- Contact Section --- */
.contact-section {
    padding: 80px 0 120px 0;
    position: relative;
}

.contact-section::after {
    content: '';
    position: absolute;
    bottom: 50px;
    right: -100px;
    width: 300px;
    height: 300px;
    background: radial-gradient(circle, var(--accent-orange-glow) 0%, transparent 70%);
    z-index: -1;
    pointer-events: none;
}

.contact-container {
    display: grid;
    grid-template-columns: 0.8fr 1.2fr;
    gap: 4rem;
    background-color: var(--bg-card);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius-lg);
    padding: 3rem;
    box-shadow: var(--shadow-glow);
}

.contact-info h3,
.contact-form-area h3 {
    font-size: 1.6rem;
    margin-bottom: 0.75rem;
}

.contact-info p {
    color: var(--text-secondary);
    margin-bottom: 2.25rem;
    font-size: 0.95rem;
}

.info-list {
    display: flex;
    flex-direction: column;
    gap: 1.75rem;
    margin-bottom: 2.5rem;
}

.info-item {
    display: flex;
    align-items: flex-start;
    gap: 1.25rem;
}

.info-item i {
    font-size: 1.25rem;
    color: var(--accent-cyan);
    margin-top: 0.25rem;
    width: 24px;
    text-align: center;
}

.info-item h4 {
    font-size: 0.9rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: 0.15rem;
}

.info-item p,
.info-item a {
    font-size: 1.05rem;
    font-weight: 600;
    color: var(--text-primary);
}

.info-item a:hover {
    color: var(--accent-cyan);
}

.social-links {
    display: flex;
    gap: 1rem;
}

.social-links a {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 44px;
    height: 44px;
    border-radius: var(--border-radius-md);
    background-color: rgba(255, 255, 255, 0.03);
    border: 1px solid var(--border-color);
    color: var(--text-secondary);
    font-size: 1.2rem;
    transition: all var(--transition-speed) ease;
}

body.light-theme .social-links a {
    background-color: rgba(15, 23, 42, 0.03);
}

.social-links a:hover {
    color: #ffffff;
    background-color: var(--accent-cyan);
    border-color: var(--accent-cyan);
    transform: translateY(-3px);
}

.contact-form-area {
    border-left: 1px solid var(--border-color);
    padding-left: 4rem;
}

.form-group {
    margin-bottom: 1.5rem;
}

.form-group label {
    display: block;
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--text-secondary);
    margin-bottom: 0.5rem;
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 0.85rem 1rem;
    background-color: rgba(255, 255, 255, 0.02);
    border: 1px solid var(--border-color);
    color: var(--text-primary);
    font-family: 'Inter', sans-serif;
    font-size: 0.95rem;
    border-radius: var(--border-radius-md);
    transition: all var(--transition-speed) ease;
}

body.light-theme .form-group input,
body.light-theme .form-group textarea {
    background-color: rgba(15, 23, 42, 0.01);
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--accent-cyan);
    box-shadow: 0 0 10px rgba(6, 182, 212, 0.15);
    background-color: rgba(255, 255, 255, 0.05);
}

/* --- Footer --- */
footer {
    border-top: 1px solid var(--border-color);
    padding: 2.5rem 0;
    background-color: var(--bg-secondary);
    font-size: 0.9rem;
    color: var(--text-muted);
}

.footer-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 1rem;
}

/* --- Keyframe Animations --- */
@keyframes rotateGlow {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

/* --- Responsive Media Queries --- */
@media (max-width: 1024px) {
    .hero-title {
        font-size: 3rem;
    }
    
    .contact-container {
        padding: 2.5rem;
        gap: 2.5rem;
    }
    
    .contact-form-area {
        padding-left: 2.5rem;
    }
}

@media (max-width: 992px) {
    .nav-links {
        display: none; /* Sẽ được hiện dưới dạng mobile menu qua JS */
    }
    
    .mobile-menu-toggle {
        display: block;
    }
    
    .hero-container {
        grid-template-columns: 1fr;
        gap: 3rem;
        text-align: center;
    }
    
    .hero-content {
        display: flex;
        flex-direction: column;
        align-items: center;
    }
    
    .hero-bio {
        text-align: center;
    }
    
    .hero-contact-quick {
        justify-content: center;
    }
    
    .hero-actions {
        justify-content: center;
    }
    
    .hero-image-area {
        order: -1; /* Đưa ảnh lên trước trên thiết bị di động */
    }
    
    .stats-grid {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }
    
    .equipment-grid {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }
    
    .skills-grid {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }
    
    .skill-desc {
        height: auto;
    }
    
    .contact-container {
        grid-template-columns: 1fr;
        gap: 3rem;
    }
    
    .contact-form-area {
        border-left: none;
        padding-left: 0;
        border-top: 1px solid var(--border-color);
        padding-top: 3rem;
    }
}

@media (max-width: 600px) {
    .hero-title {
        font-size: 2.25rem;
    }
    
    .avatar-container {
        width: 260px;
        height: 260px;
    }
    
    .image-glow-ring {
        width: 276px;
        height: 276px;
    }
    
    .timeline {
        padding-left: 1.5rem;
    }
    
    .timeline-dot {
        left: -32px;
    }
    
    .timeline-content {
        padding: 1.5rem;
    }
    
    .job-highlights {
        flex-direction: column;
        gap: 0.75rem;
    }
    
    .portfolio-promo {
        padding: 1.75rem;
        flex-direction: column;
        text-align: center;
        gap: 1.5rem;
    }
    
    .promo-icon {
        display: none;
    }
    
    .footer-content {
        flex-direction: column;
        text-align: center;
    }
}

/* Mobile Active Menu Class (Sẽ toggle bằng JS) */
.nav-links.mobile-active {
    display: flex;
    flex-direction: column;
    position: absolute;
    top: 70px;
    left: 0;
    width: 100%;
    background-color: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
    padding: 2rem;
    gap: 1.5rem;
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.2);
    animation: fadeInUp 0.3s ease;
}

/* ==========================================================================
   CSS PRINT STYLES (@media print) - OPTIMIZED FOR A4 PORTRAIT
   ========================================================================== */
@media print {
    /* Reset & Setup A4 Page - Adjust margins: top margin is 1.8cm to make it look balanced and airy, bottom is 1.2cm */
    @page {
        size: A4 portrait;
        margin: 1.8cm 1.5cm 1.2cm 1.5cm;
    }
    
    :root {
        --bg-primary: #ffffff !important;
        --bg-secondary: #ffffff !important;
        --bg-card: #ffffff !important;
        --text-primary: #1e293b !important; /* Xám đậm thay vì đen hoàn toàn để tạo độ tinh tế */
        --text-secondary: #475569 !important;
        --text-muted: #64748b !important;
        --border-color: #cbd5e1 !important;
        --accent-cyan: #0284c7 !important; /* Xanh đậm để đọc được rõ */
        --accent-orange: #d97706 !important;
    }
    
    body {
        background-color: #ffffff !important;
        color: #1e293b !important;
        font-size: 9pt !important; /* Giảm nhẹ font size xuống 9pt để vừa vặn trang giấy */
        line-height: 1.35 !important;
        padding: 0 !important; /* Reset body padding to prevent double margin issue */
    }
    
    /* Ẩn tất cả các phần tương tác và thừa thãi khi in */
    #navbar, 
    #theme-toggle, 
    .btn-print, 
    .mobile-menu-toggle,
    .hero-actions,
    .contact-section, /* Ẩn toàn bộ phần Liên hệ/Kết nối ở cuối trang khi in vì trên đầu đã có đủ thông tin liên hệ */
    .social-links,
    .image-glow-ring,
    footer,
    .stats-section, /* Ẩn toàn bộ phần số liệu nổi bật khi in vì thông tin đã có chi tiết ở dưới và để tiết kiệm diện tích */
    .timeline-dot,
    .equip-header i,
    .skill-icon {
        display: none !important;
    }
    
    /* Điều chỉnh các phần hiển thị */
    .container {
        width: 100% !important;
        max-width: 100% !important;
        padding: 0 !important;
        margin: 0 !important;
    }
    
    /* Hero Section optimized for print */
    .hero-section {
        padding: 0 0 0.75rem 0 !important;
        border-bottom: 2px solid #e2e8f0 !important;
        margin-bottom: 1rem !important;
    }
    
    .hero-container {
        display: grid !important;
        grid-template-columns: 3.5fr 1.2fr !important; /* Chia tỷ lệ thông tin và ảnh */
        gap: 1.5rem !important;
        align-items: center !important;
        text-align: left !important;
    }
    
    .hero-image-area {
        order: 1 !important;
    }
    
    .avatar-container {
        width: 110px !important;
        height: 110px !important;
        border: 2px solid #cbd5e1 !important;
        box-shadow: none !important;
    }
    
    .hero-title {
        font-size: 24pt !important;
        margin-bottom: 0.25rem !important;
        color: #0f172a !important;
        background: none !important;
        -webkit-text-fill-color: initial !important;
    }
    
    .hero-subtitle {
        font-size: 11pt !important;
        color: var(--accent-cyan) !important;
        margin-bottom: 0.75rem !important;
    }
    
    .badge {
        display: none !important; /* Ẩn các badge động */
    }
    
    .hero-bio {
        font-size: 9.5pt !important;
        margin-bottom: 1rem !important;
        color: var(--text-secondary) !important;
    }
    
    .hero-contact-quick {
        margin-bottom: 0 !important;
        gap: 1.2rem !important;
    }
    
    .hero-contact-quick span {
        font-size: 9pt !important;
        font-weight: 500 !important;
    }
    

    
    /* Section Headers */
    .section-header {
        margin-bottom: 1rem !important;
        text-align: left !important;
    }
    
    .section-title {
        font-size: 13pt !important;
        font-weight: 800 !important;
        padding-bottom: 0.25rem !important;
        margin-bottom: 0.5rem !important;
        text-transform: uppercase !important;
        letter-spacing: 0.05em !important;
        color: #0f172a !important;
        background: none !important;
        -webkit-text-fill-color: initial !important;
        display: block !important;
        border-bottom: 1.5px solid #cbd5e1 !important;
    }
    
    .section-title::after {
        display: none !important;
    }
    
    .section-subtitle {
        display: none !important;
    }
    
    /* Timeline & Experience optimized for print space */
    .experience-section {
        padding: 0 !important;
        margin-bottom: 1rem !important;
    }
    
    .timeline {
        padding-left: 0 !important;
        max-width: 100% !important;
    }
    
    .timeline::before {
        display: none !important;
    }
    
    .timeline-item {
        margin-bottom: 0.7rem !important; /* Giảm khoảng cách giữa các công việc để không bị tràn trang */
        page-break-inside: avoid;
    }
    
    .timeline-date {
        font-size: 8.5pt !important;
        font-weight: 700 !important;
        margin-bottom: 0.15rem !important;
    }
    
    .timeline-content {
        padding: 0 !important;
        border: none !important;
        background: none !important;
        backdrop-filter: none !important;
        box-shadow: none !important;
    }
    
    .job-title {
        font-size: 11pt !important;
        color: #0f172a !important;
    }
    
    .job-company {
        font-size: 9pt !important;
        margin-bottom: 0.25rem !important;
    }
    
    .job-highlights {
        display: flex !important;
        flex-direction: row !important;
        gap: 1rem !important;
        border: 1px dashed #cbd5e1 !important;
        background: none !important;
        padding: 0.25rem 0.6rem !important;
        margin-bottom: 0.35rem !important;
    }
    
    .highlight-value {
        font-size: 9.5pt !important;
    }
    
    .job-badge {
        display: inline-block !important;
        border: 1px solid #cbd5e1 !important;
        background: none !important;
        color: #dc2626 !important;
        font-size: 7.5pt !important;
        padding: 0.1rem 0.4rem !important;
        margin-bottom: 0.5rem !important;
    }
    
    .job-details {
        padding-left: 1rem !important;
    }
    
    .job-details li {
        font-size: 9pt !important;
        margin-bottom: 0.15rem !important; /* Thu nhỏ khoảng cách dòng */
        line-height: 1.3 !important;
    }
    
    /* Equipment & Portfolio Section for Print */
    .equipment-section {
        padding: 0 !important;
        margin-bottom: 1.5rem !important;
        page-break-before: always !important; /* Chủ động ngắt trang tại đây để CV chia làm 2 trang A4 cân đối, không bị tràn lửng lơ */
    }
    
    .portfolio-promo {
        padding: 0.75rem 1rem !important;
        margin-bottom: 1rem !important;
        background: #f8fafc !important;
        border: 1px solid #cbd5e1 !important;
    }
    
    .promo-text h3 {
        font-size: 10pt !important;
    }
    
    .promo-text p {
        font-size: 8.5pt !important;
        margin-bottom: 0.25rem !important;
    }
    
    .promo-link {
        font-size: 9.5pt !important;
        font-weight: 700 !important;
        border-bottom: 1px solid var(--accent-cyan) !important;
        padding-bottom: 0 !important;
    }
    
    .subsection-title {
        font-size: 10pt !important;
        margin-bottom: 0.75rem !important;
        font-weight: 700 !important;
    }
    
    .equipment-grid {
        grid-template-columns: repeat(4, 1fr) !important; /* In 4 cột nằm ngang để tiết kiệm giấy dọc */
        gap: 0.75rem !important;
        margin-bottom: 1rem !important;
    }
    
    .equipment-card {
        padding: 0.6rem !important;
        border: 1px solid #cbd5e1 !important;
        border-radius: var(--border-radius-sm) !important;
        background: none !important;
        backdrop-filter: none !important;
        page-break-inside: avoid;
    }
    
    .equip-category {
        font-size: 7pt !important;
    }
    
    .equip-name {
        font-size: 9pt !important;
        margin-bottom: 0.15rem !important;
        color: #0f172a !important;
    }
    
    .equip-status {
        font-size: 7.5pt !important;
        margin-bottom: 0.25rem !important;
    }
    
    .status-dot {
        width: 6px !important;
        height: 6px !important;
        box-shadow: none !important;
    }
    
    .equip-desc {
        font-size: 8pt !important;
        line-height: 1.3 !important;
    }
    
    .equipment-footer {
        padding: 0.75rem !important;
        border-radius: var(--border-radius-sm) !important;
    }
    
    .tech-tag {
        font-size: 8.5pt !important;
    }
    
    /* Skills Section for Print */
    .skills-section {
        padding: 0 !important;
        margin-bottom: 1.5rem !important;
        page-break-inside: avoid;
    }
    
    .skills-grid {
        grid-template-columns: repeat(3, 1fr) !important; /* 3 cột khi in */
        gap: 1rem !important;
    }
    
    .skill-card {
        padding: 0.75rem !important;
        border: 1px solid #cbd5e1 !important;
        border-radius: var(--border-radius-sm) !important;
        background: none !important;
        backdrop-filter: none !important;
        page-break-inside: avoid;
    }
    
    .skill-card h3 {
        font-size: 9.5pt !important;
        margin-bottom: 0.25rem !important;
        color: #0f172a !important;
    }
    
    .skill-desc {
        font-size: 8pt !important;
        margin-bottom: 0.5rem !important;
        height: auto !important; /* Cho phép giãn tự nhiên */
        line-height: 1.3 !important;
    }
    
    .skill-level {
        display: none !important; /* Không cần thanh tiến trình trên giấy */
    }
    
}