/* ===========================
   CSS CUSTOM PROPERTIES
   =========================== */
:root {
    /* Colors */
    --color-background: #F9FAFF;
    --color-text-primary: #25282B;
    --color-text-secondary: #5A5E62;
    --color-accent: #4A90E2;
    --color-nav-bg: rgba(249, 250, 255, 0.95);
    --color-white: #FFFFFF;

    /* Typography */
    --font-family-primary: 'Raleway', sans-serif;
    --font-family-heading: 'Playfair Display', serif;
    --font-family-body: 'Nunito', sans-serif;
    --font-size-base: 18px;
    --font-size-h1: 2.5rem;
    --font-size-h2: 2rem;
    --font-size-h3: 1.5rem;
    --font-weight-light: 300;
    --font-weight-regular: 400;
    --font-weight-medium: 500;
    --font-weight-semibold: 600;
    --font-weight-bold: 700;
    --line-height-base: 1.7;
    --line-height-heading: 1.3;

    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    --spacing-xxl: 5rem;

    /* Layout */
    --container-max-width: 1200px;
    --navbar-height: 70px;

    /* Transitions */
    --transition-fast: 0.2s ease;
    --transition-medium: 0.3s ease;
    --transition-slow: 0.5s ease;

    /* Shadows */
    --shadow-soft: 0 2px 10px rgba(0, 0, 0, 0.05);
    --shadow-medium: 0 4px 20px rgba(0, 0, 0, 0.1);
}

/* ===========================
   RESET & BASE STYLES
   =========================== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
    font-size: var(--font-size-base);
}

body {
    font-family: var(--font-family-primary);
    background-color: var(--color-background);
    color: var(--color-text-primary);
    line-height: var(--line-height-base);
    overflow-x: hidden;
}

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

a {
    text-decoration: none;
    color: inherit;
    transition: color var(--transition-fast);
}

ul {
    list-style: none;
}

button {
    font-family: inherit;
    cursor: pointer;
    border: none;
    background: none;
}

/* ===========================
   TYPOGRAPHY
   =========================== */
h1,
h2,
h3,
h4,
h5,
h6 {
    line-height: var(--line-height-heading);
    font-weight: var(--font-weight-semibold);
    margin-bottom: var(--spacing-md);
}

h1 {
    font-size: var(--font-size-h1);
    font-weight: var(--font-weight-bold);
}

h2 {
    font-size: var(--font-size-h2);
}

h3 {
    font-size: var(--font-size-h3);
}

p {
    margin-bottom: var(--spacing-md);
}

/* ===========================
   LAYOUT UTILITIES
   =========================== */
.container {
    max-width: var(--container-max-width);
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
}

.section {
    padding: var(--spacing-xxl) 0;
    min-height: 100vh;
    display: flex;
    align-items: center;
}

.section-title {
    text-align: center;
    margin-bottom: var(--spacing-xl);
    font-size: var(--font-size-h2);
    font-family: var(--font-family-heading);
}

/* ===========================
   NAVIGATION BAR
   =========================== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: var(--navbar-height);
    background-color: var(--color-background);
    border: none;
    box-shadow: none;
    z-index: 1000;
    transition: all var(--transition-medium);
}

.nav-container {
    max-width: var(--container-max-width);
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
}

/* Language Toggle */
.lang-toggle {
    position: absolute;
    right: var(--spacing-lg);
    font-size: 0.9rem;
    font-weight: var(--font-weight-semibold);
    color: var(--color-text-secondary);
    padding: var(--spacing-xs) var(--spacing-sm);
    transition: all var(--transition-fast);
}

.lang-toggle:hover {
    color: var(--color-text-primary);
}

/* Desktop Navigation */
.nav-links {
    display: flex;
    gap: var(--spacing-xl);
    align-items: center;
}

.nav-link {
    font-size: 1rem;
    font-weight: var(--font-weight-medium);
    color: var(--color-text-primary);
    padding: var(--spacing-xs) var(--spacing-sm);
    position: relative;
    transition: color var(--transition-fast);
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 0;
    height: 2px;
    background-color: var(--color-text-primary);
    transition: width var(--transition-medium);
}

.nav-link:hover::after,
.nav-link.active::after {
    width: 80%;
}

.nav-link.active {
    color: var(--color-text-primary);
}

/* Hamburger Button (Mobile) */
.hamburger {
    display: none;
    flex-direction: column;
    gap: 5px;
    padding: var(--spacing-xs);
    z-index: 1001;
}

.hamburger-line {
    width: 25px;
    height: 3px;
    background-color: var(--color-text-primary);
    border-radius: 2px;
    transition: all var(--transition-medium);
}

.hamburger.active .hamburger-line:nth-child(1) {
    transform: rotate(45deg) translate(8px, 8px);
}

.hamburger.active .hamburger-line:nth-child(2) {
    opacity: 0;
}

.hamburger.active .hamburger-line:nth-child(3) {
    transform: rotate(-45deg) translate(7px, -7px);
}

/* Mobile Menu */
.mobile-menu {
    position: fixed;
    top: var(--navbar-height);
    left: 0;
    right: 0;
    background-color: var(--color-background);
    padding: var(--spacing-lg);
    transform: translateY(-100%);
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-medium);
    border: none;
    box-shadow: none;
}

.mobile-menu.active {
    transform: translateY(0);
    opacity: 1;
    visibility: visible;
}

.mobile-nav-links {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

.mobile-nav-links .nav-link {
    font-size: 1.2rem;
    padding: var(--spacing-sm);
    text-align: center;
}

/* Add padding to body for fixed navbar */
body {
    padding-top: var(--navbar-height);
}

/* ===========================
   BIOGRAPHY SECTION
   =========================== */
#biography {
    background-color: var(--color-background);
}

.bio-grid {
    display: grid;
    grid-template-columns: 1fr 1.5fr;
    gap: var(--spacing-xl);
    align-items: start;
}

.bio-image {
    position: relative;
    width: 100%;
    max-width: 400px;
}

.bio-image img {
    width: 100%;
    height: auto;
    border-radius: 4px;
    box-shadow: var(--shadow-medium);
}

.bio-content {
    padding: var(--spacing-lg) 0;
}

.bio-name {
    font-family: var(--font-family-heading);
    font-size: var(--font-size-h1);
    font-weight: var(--font-weight-bold);
    color: var(--color-text-primary);
    margin-bottom: var(--spacing-lg);
    line-height: 1.2;
}

.bio-name-vietnamese {
    display: inline-block;
    font-weight: var(--font-weight-regular);
}

.bio-content p {
    font-family: var(--font-family-body);
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-md);
    text-align: justify;
    line-height: var(--line-height-base);
}

.bio-content .signature {
    max-width: 150px;
    margin-top: var(--spacing-lg);
    margin-left: 0;
    opacity: 0.9;
}

/* Mobile Layout for Biography */
@media (max-width: 768px) {
    .bio-grid {
        grid-template-columns: 1fr;
        gap: var(--spacing-lg);
    }

    .bio-image {
        max-width: 100%;
        margin: 0 auto;
    }

    .bio-name {
        text-align: center;
    }

    .bio-name-vietnamese {
        display: block;
        margin-top: var(--spacing-xs);
    }

    .bio-content p {
        text-align: left;
    }

    .bio-content .signature {
        margin: var(--spacing-lg) auto 0;
    }
}

/* ===========================
   SKILLS SECTION
   =========================== */
#skills {
    background-color: var(--color-background);
}

.skills-list {
    max-width: 900px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xl);
}

.skill-category {
    padding: var(--spacing-lg);
    background-color: var(--color-white);
    border-radius: 16px;
    box-shadow: var(--shadow-soft);
    transition: box-shadow var(--transition-medium);
}

.skill-category:hover {
    box-shadow: var(--shadow-medium);
}

.skill-title {
    font-family: var(--font-family-heading);
    font-size: var(--font-size-h3);
    font-weight: var(--font-weight-semibold);
    color: var(--color-text-primary);
    margin-bottom: var(--spacing-md);
}

.skill-description,
.skill-tech {
    font-family: var(--font-family-body);
    color: var(--color-text-secondary);
    line-height: var(--line-height-base);
    margin-bottom: var(--spacing-sm);
}

.skill-description strong,
.skill-tech strong {
    color: var(--color-text-primary);
    font-weight: var(--font-weight-semibold);
}

/* Mobile Layout for Skills */
@media (max-width: 768px) {
    .skills-list {
        gap: var(--spacing-lg);
    }

    .skill-category {
        padding: var(--spacing-md);
    }

    .skill-title {
        font-size: 1.15rem;
    }
}

/* ===========================
   PORTFOLIO SECTION
   =========================== */
#portfolio {
    background-color: var(--color-background);
}

.project-list {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xxl);
    margin-top: var(--spacing-xl);
}

.project-card {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 0;
    align-items: stretch;
    padding: 0;
    background-color: var(--color-white);
    border-radius: 16px;
    box-shadow: var(--shadow-soft);
    transition: all var(--transition-medium);
    overflow: hidden;
}

.project-card:hover {
    box-shadow: var(--shadow-medium);
    transform: translateY(-5px);
}

/* Reverse layout for alternating projects */
.project-card-reverse {
    grid-template-columns: 1fr 1fr;
}

.project-image {
    width: 100%;
    height: 100%;
    display: flex;
    align-items: stretch;
    min-height: 400px;
}

.project-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.project-content {
    padding: var(--spacing-xl);
    display: flex;
    flex-direction: column;
    justify-content: center;
}

.project-title {
    font-family: var(--font-family-heading);
    font-size: var(--font-size-h3);
    font-weight: var(--font-weight-semibold);
    color: var(--color-text-primary);
    margin-bottom: var(--spacing-md);
}

.project-meta {
    font-family: var(--font-family-body);
    color: var(--color-text-secondary);
    font-size: 0.95rem;
    margin-bottom: var(--spacing-sm);
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
}

.project-meta i {
    width: 20px;
    height: 20px;
    flex-shrink: 0;
}

/* Ensure all SVG icons in project-meta are 20px */
.project-meta i svg,
.project-meta svg {
    width: 20px !important;
    height: 20px !important;
    min-width: 20px;
    min-height: 20px;
}

.project-details {
    list-style: none;
    margin-top: var(--spacing-md);
    margin-bottom: var(--spacing-md);
}

.project-details li {
    font-family: var(--font-family-body);
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-sm);
    display: flex;
    align-items: flex-start;
    gap: var(--spacing-sm);
    line-height: var(--line-height-base);
}

.project-details li i {
    width: 20px;
    height: 20px;
    margin-top: 4px;
    flex-shrink: 0;
    color: var(--color-accent);
}

/* Target the actual SVG icons that Lucide generates - force 20px */
.project-details li i svg,
.project-details li svg {
    width: 20px !important;
    height: 20px !important;
    min-width: 20px;
    min-height: 20px;
}

/* Make text-based icons thicker to visually match other icons */
.project-details li svg.lucide-book-text,
.project-details li svg.lucide-file-text {
    stroke-width: 2.5;
}

.project-link-text {
    font-family: var(--font-family-body);
    color: var(--color-accent);
    font-size: 0.9rem;
    word-break: break-all;
    margin-top: var(--spacing-sm);
}

/* Mobile Layout for Portfolio */
@media (max-width: 768px) {
    .project-list {
        gap: var(--spacing-xl);
    }

    .project-card,
    .project-card-reverse {
        grid-template-columns: 1fr;
        gap: var(--spacing-lg);
        padding: var(--spacing-lg);
    }

    .project-content {
        padding: 0;
    }

    .project-title {
        font-size: 1.25rem;
    }

    .project-meta {
        font-size: 0.9rem;
    }

    .project-details li {
        font-size: 0.9rem;
    }
}

/* ===========================
   CONTACT SECTION
   =========================== */
#contact {
    background-color: var(--color-background);
}

.contact-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-xxl);
    align-items: start;
    max-width: 1000px;
    margin: 0 auto;
}

.contact-info {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
    padding-top: 0;
    margin-top: 0;
}

.contact-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-family: var(--font-family-body);
    color: var(--color-text-secondary);
    font-size: 0.95rem;
}

.contact-item i {
    width: 20px;
    height: 20px;
    flex-shrink: 0;
    color: var(--color-text-primary);
}

.contact-item i svg,
.contact-item svg {
    width: 20px !important;
    height: 20px !important;
    min-width: 20px;
    min-height: 20px;
}

.contact-item a {
    color: var(--color-accent);
    word-break: break-all;
    transition: color var(--transition-fast);
}

.contact-item a:hover {
    color: var(--color-text-primary);
    text-decoration: underline;
}

.contact-message {
    font-family: var(--font-family-body);
    color: var(--color-text-secondary);
    line-height: var(--line-height-base);
    padding-top: 0;
    margin-top: 0;
}

.contact-message p {
    margin-bottom: var(--spacing-md);
}

.contact-message p:first-child {
    margin-top: 0;
}

/* Mobile Layout for Contact */
@media (max-width: 768px) {
    .contact-grid {
        grid-template-columns: 1fr;
        gap: var(--spacing-xl);
    }

    .contact-message {
        text-align: left;
    }
}

/* ===========================
   SCROLL ANIMATIONS
   =========================== */
.animate-on-scroll {
    opacity: 0;
    transition: all 1.5s ease-out;
}

.animate-on-scroll.animated {
    opacity: 1;
}

/* Slide Up Animation */
.animate-on-scroll[data-animation="slide-up"] {
    transform: translateY(50px);
}

.animate-on-scroll[data-animation="slide-up"].animated {
    transform: translateY(0);
}

/* Slide Down Animation */
.animate-on-scroll[data-animation="slide-down"] {
    transform: translateY(-50px);
}

.animate-on-scroll[data-animation="slide-down"].animated {
    transform: translateY(0);
}

/* Slide Left Animation */
.animate-on-scroll[data-animation="slide-left"] {
    transform: translateX(-50px);
}

.animate-on-scroll[data-animation="slide-left"].animated {
    transform: translateX(0);
}

/* Slide Right Animation */
.animate-on-scroll[data-animation="slide-right"] {
    transform: translateX(50px);
}

.animate-on-scroll[data-animation="slide-right"].animated {
    transform: translateX(0);
}

/* Fade In Animation */
.animate-on-scroll[data-animation="fade-in"].animated {
    opacity: 1;
}

/* ===========================
   RESPONSIVE BREAKPOINTS
   =========================== */

/* Tablet */
@media (max-width: 1024px) {
    :root {
        --font-size-h1: 2rem;
        --font-size-h2: 1.75rem;
        --font-size-h3: 1.25rem;
        --spacing-xxl: 4rem;
    }

    .container {
        padding: 0 var(--spacing-md);
    }
}

/* Mobile */
@media (max-width: 768px) {
    :root {
        --font-size-base: 16px;
        --font-size-h1: 1.75rem;
        --font-size-h2: 1.5rem;
        --font-size-h3: 1.15rem;
        --spacing-xxl: 3rem;
    }

    .container {
        padding: 0 var(--spacing-md);
    }

    .section {
        min-height: auto;
        padding: var(--spacing-xl) 0;
    }

    /* Show hamburger menu on mobile */
    .nav-links {
        display: none;
    }

    .hamburger {
        display: flex;
    }

    .nav-container {
        justify-content: flex-end;
        gap: var(--spacing-md);
    }

    /* Fix language toggle position on mobile */
    .lang-toggle {
        position: static;
        order: 2;
    }

    .hamburger {
        order: 1;
    }
}