/*
	Academic Website - Main CSS
	Simplified and optimized for academic presentation
	Based on design requirements for clean, professional styling
*/

/* CSS Reset and Base Styles */
html, body, div, span, applet, object,
iframe, h1, h2, h3, h4, h5, h6, p, blockquote,
pre, a, abbr, acronym, address, big, cite,
code, del, dfn, em, img, ins, kbd, q, s, samp,
small, strike, strong, sub, sup, tt, var, b,
u, i, center, dl, dt, dd, ol, ul, li, fieldset,
form, label, legend, table, caption, tbody,
tfoot, thead, tr, th, td, article, aside,
canvas, details, embed, figure, figcaption,
footer, header, hgroup, menu, nav, output, ruby,
section, summary, time, mark, audio, video {
	margin: 0;
	padding: 0;
	border: 0;
	font-size: 100%;
	font: inherit;
	vertical-align: baseline;
}

article, aside, details, figcaption, figure,
footer, header, hgroup, menu, nav, section {
	display: block;
}

body {
	line-height: 1;
}

ol, ul {
	list-style: none;
}

blockquote, q {
	quotes: none;
}

blockquote:before, blockquote:after, q:before, q:after {
	content: '';
	content: none;
}

table {
	border-collapse: collapse;
	border-spacing: 0;
}

body {
	-webkit-text-size-adjust: none;
}

mark {
	background-color: transparent;
	color: inherit;
}

input::-moz-focus-inner {
	border: 0;
	padding: 0;
}

input, select, textarea {
	-moz-appearance: none;
	-webkit-appearance: none;
	-ms-appearance: none;
	appearance: none;
}

/* Academic Design System Variables */
:root {
	/* Academic Color Palette */
	--color-primary: #1e3a8a;        /* Academic deep blue */
	--color-text: #1f2937;           /* Dark gray for text */
	--color-text-light: #6b7280;     /* Light gray for secondary text */
	--color-background: #ffffff;      /* Clean white background */
	--color-border: #e5e7eb;         /* Light border */
	--color-accent: #dc2626;         /* Academic red for emphasis */
	--color-muted: #f9fafb;          /* Very light gray for backgrounds */
	
	/* Academic Typography System */
	--font-primary: 'Inter', 'Source Sans Pro', sans-serif;     /* Clean sans-serif */
	--font-heading: 'Crimson Text', 'Times New Roman', serif;   /* Elegant serif for headings */
	
	/* Font Scale */
	--text-xs: 0.75rem;
	--text-sm: 0.875rem;
	--text-base: 1rem;
	--text-lg: 1.125rem;
	--text-xl: 1.25rem;
	--text-2xl: 1.5rem;
	--text-3xl: 2rem;
	--text-4xl: 2.5rem;
	
	/* Academic Spacing System */
	--space-xs: 0.5rem;
	--space-sm: 1rem;
	--space-md: 1.5rem;
	--space-lg: 2rem;
	--space-xl: 3rem;
	--space-2xl: 4rem;
	--space-3xl: 6rem;
	
	/* Layout */
	--max-width: 1200px;
	--border-radius: 8px;
	--transition: 0.2s ease;
}

/* Basic Styles */
@-ms-viewport {
	width: device-width;
}

body {
	-ms-overflow-style: scrollbar;
}

@media screen and (max-width: 480px) {
	html, body {
		min-width: 320px;
	}
}

html {
	box-sizing: border-box;
}

*, *:before, *:after {
	box-sizing: inherit;
}

body {
	background: var(--color-background);
	color: var(--color-text);
	font-family: var(--font-primary);
	font-size: var(--text-base);
	font-weight: 400;
	line-height: 1.6;
}

body.is-preload *, body.is-preload *:before, body.is-preload *:after {
	animation: none !important;
	transition: none !important;
}

/* Academic Typography */
h1, h2, h3, h4, h5, h6 {
	color: var(--color-text);
	font-family: var(--font-heading);
	font-weight: 600;
	line-height: 1.3;
	margin: 0 0 var(--space-md) 0;
}

h1 {
	font-size: var(--text-4xl);
	letter-spacing: -0.025em;
}

h2 {
	font-size: var(--text-3xl);
}

h3 {
	font-size: var(--text-2xl);
}

h4 {
	font-size: var(--text-xl);
}

h5 {
	font-size: var(--text-lg);
}

h6 {
	font-size: var(--text-base);
}

@media screen and (max-width: 768px) {
	h1 {
		font-size: var(--text-3xl);
	}
	
	h2 {
		font-size: var(--text-2xl);
	}
	
	h3 {
		font-size: var(--text-xl);
	}
}

p {
	margin: 0 0 var(--space-md) 0;
	line-height: 1.6;
}

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

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

strong, b {
	font-weight: 600;
}

em, i {
	font-style: italic;
}

code {
	background: var(--color-muted);
	border-radius: var(--border-radius);
	border: 1px solid var(--color-border);
	font-family: 'SF Mono', 'Monaco', 'Consolas', monospace;
	font-size: var(--text-sm);
	padding: 0.25em 0.5em;
}

pre {
	background: var(--color-muted);
	border-radius: var(--border-radius);
	border: 1px solid var(--color-border);
	font-family: 'SF Mono', 'Monaco', 'Consolas', monospace;
	font-size: var(--text-sm);
	margin: 0 0 var(--space-md) 0;
	overflow-x: auto;
	padding: var(--space-sm);
}

pre code {
	background: none;
	border: none;
	padding: 0;
}

blockquote {
	border-left: 4px solid var(--color-primary);
	font-style: italic;
	margin: 0 0 var(--space-md) 0;
	padding: var(--space-sm) 0 var(--space-sm) var(--space-md);
}

hr {
	border: 0;
	border-bottom: 1px solid var(--color-border);
	margin: var(--space-xl) 0;
}

/* Lists */
ol {
	list-style: decimal;
	margin: 0 0 var(--space-md) 0;
	padding-left: var(--space-lg);
}

ul {
	list-style: disc;
	margin: 0 0 var(--space-md) 0;
	padding-left: var(--space-lg);
}

li {
	padding-left: var(--space-xs);
	margin-bottom: var(--space-xs);
}

/* Layout Container */
.container {
	max-width: var(--max-width);
	margin: 0 auto;
	padding: 0 var(--space-md);
}

/* Academic Buttons */
.button, button, input[type="submit"], input[type="button"] {
	background: var(--color-primary);
	border: none;
	border-radius: var(--border-radius);
	color: white;
	cursor: pointer;
	display: inline-block;
	font-family: var(--font-primary);
	font-size: var(--text-base);
	font-weight: 500;
	padding: var(--space-sm) var(--space-lg);
	text-align: center;
	text-decoration: none;
	transition: all var(--transition);
}

.button:hover, button:hover, input[type="submit"]:hover, input[type="button"]:hover {
	background: var(--color-accent);
	color: white;
	transform: translateY(-1px);
}

.button.secondary {
	background: transparent;
	border: 2px solid var(--color-primary);
	color: var(--color-primary);
}

.button.secondary:hover {
	background: var(--color-primary);
	color: white;
}

/* Forms */
input[type="text"], input[type="email"], input[type="tel"], 
input[type="password"], textarea, select {
	background: var(--color-background);
	border: 1px solid var(--color-border);
	border-radius: var(--border-radius);
	color: var(--color-text);
	font-family: var(--font-primary);
	font-size: var(--text-base);
	padding: var(--space-sm);
	width: 100%;
	transition: border-color var(--transition);
}

input[type="text"]:focus, input[type="email"]:focus, input[type="tel"]:focus,
input[type="password"]:focus, textarea:focus, select:focus {
	border-color: var(--color-primary);
	outline: none;
	box-shadow: 0 0 0 3px rgba(30, 58, 138, 0.1);
}

textarea {
	min-height: 120px;
	resize: vertical;
}

/* Header - Clean Academic Navigation */
#header {
	background: var(--color-background);
	border-bottom: 1px solid var(--color-border);
	padding: var(--space-md) 0;
	position: sticky;
	top: 0;
	z-index: 1000;
	box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
}

#header .inner {
	max-width: var(--max-width);
	margin: 0 auto;
	padding: 0 var(--space-md);
	display: flex;
	align-items: center;
	justify-content: space-between;
}

/* Logo */
#header .logo {
	display: flex;
	align-items: center;
	gap: var(--space-sm);
	color: var(--color-text);
	text-decoration: none;
	font-size: var(--text-xl);
	font-weight: 600;
	font-family: var(--font-heading);
	transition: color var(--transition);
}

#header .logo:hover {
	color: var(--color-primary);
}

#header .logo .symbol img {
	width: 32px;
	height: 32px;
}

/* Main Navigation - Horizontal Menu */
#header .main-nav {
	display: flex;
	align-items: center;
	gap: var(--space-lg);
}

#header .main-nav ul {
	list-style: none;
	margin: 0;
	padding: 0;
	display: flex;
	align-items: center;
	gap: var(--space-xs);
}

#header .main-nav a {
	color: var(--color-text);
	text-decoration: none;
	font-weight: 500;
	font-size: var(--text-sm);
	padding: var(--space-sm) var(--space-md);
	border-radius: var(--border-radius);
	transition: all var(--transition);
	white-space: nowrap;
}

#header .main-nav a:hover,
#header .main-nav a.active {
	background: var(--color-primary);
	color: white;
}

/* Language Toggle */
#header .language-toggle {
	color: var(--color-text-light) !important;
	font-size: var(--text-sm);
	border-left: 1px solid var(--color-border);
	margin-left: var(--space-sm);
	padding-left: var(--space-md) !important;
}

#header .language-toggle:hover {
	color: var(--color-primary) !important;
	background: transparent !important;
}

/* Mobile Menu Toggle Button */
.menu-toggle {
	display: none;
	background: none;
	border: none;
	cursor: pointer;
	padding: var(--space-xs);
	color: var(--color-text);
	font-size: var(--text-lg);
	border-radius: var(--border-radius);
	transition: all var(--transition);
	min-width: 44px;
	min-height: 44px;
	align-items: center;
	justify-content: center;
}

.menu-toggle:hover {
	color: var(--color-primary);
	background: var(--color-muted);
}

.menu-toggle:focus {
	outline: 2px solid var(--color-primary);
	outline-offset: 2px;
}

/* Mobile Navigation - Full Screen Overlay Menu */
@media screen and (max-width: 768px) {
	#header {
		padding: var(--space-sm) 0;
	}
	
	#header .inner {
		flex-direction: row;
		justify-content: space-between;
		align-items: center;
		padding: 0 var(--space-sm);
	}
	
	.menu-toggle {
		display: flex;
		z-index: 1002;
		position: relative;
	}
	
	/* Full screen overlay with scroll support */
	#header .main-nav {
		position: fixed;
		top: 0;
		left: 0;
		right: 0;
		bottom: 0;
		background: rgba(255, 255, 255, 0.95);
		backdrop-filter: blur(10px);
		-webkit-backdrop-filter: blur(10px);
		transform: translateX(100%);
		opacity: 0;
		visibility: hidden;
		transition: all 0.3s ease;
		z-index: 1001;
		display: flex;
		align-items: flex-start;
		justify-content: center;
		overflow-y: auto;
		-webkit-overflow-scrolling: touch;
		padding: var(--space-xl) var(--space-md);
	}
	
	#header .main-nav.active {
		transform: translateX(0);
		opacity: 1;
		visibility: visible;
	}
	
	/* Close button */
	.menu-close {
		position: absolute;
		top: var(--space-lg);
		right: var(--space-lg);
		background: none;
		border: none;
		cursor: pointer;
		padding: var(--space-sm);
		color: var(--color-text);
		font-size: var(--text-xl);
		border-radius: 50%;
		width: 44px;
		height: 44px;
		display: flex;
		align-items: center;
		justify-content: center;
		transition: all var(--transition);
		z-index: 1002;
	}
	
	.menu-close:hover {
		background: var(--color-muted);
		color: var(--color-primary);
		transform: rotate(90deg);
	}
	
	.menu-close:focus {
		outline: 2px solid var(--color-primary);
		outline-offset: 2px;
	}

	/* Menu content container with adaptive sizing */
	#header .main-nav ul {
		flex-direction: column;
		gap: var(--space-md);
		padding: var(--space-lg);
		background: var(--color-background);
		border-radius: var(--border-radius);
		box-shadow: 0 20px 60px rgba(0, 0, 0, 0.15);
		min-width: 280px;
		max-width: 90vw;
		width: 100%;
		max-width: 400px;
		text-align: center;
		border: 1px solid var(--color-border);
		position: relative;
		margin: auto;
		margin-top: var(--space-2xl);
		margin-bottom: var(--space-2xl);
		max-height: calc(100vh - 4rem);
		overflow-y: auto;
	}
	
	#header .main-nav a {
		display: flex;
		padding: var(--space-sm) var(--space-lg);
		font-size: var(--text-base);
		font-weight: 500;
		text-align: center;
		border-radius: var(--border-radius);
		transition: all var(--transition);
		min-height: 44px;
		align-items: center;
		justify-content: center;
		white-space: nowrap;
	}
	
	#header .main-nav a:hover,
	#header .main-nav a.active {
		background: var(--color-primary);
		color: white;
		transform: translateY(-2px);
		box-shadow: 0 4px 12px rgba(30, 58, 138, 0.3);
	}
	
	#header .language-toggle {
		border-left: none;
		border-top: 2px solid var(--color-border);
		margin-left: 0;
		margin-top: var(--space-sm);
		padding-top: var(--space-sm) !important;
		padding-left: var(--space-lg) !important;
		color: var(--color-text-light) !important;
		font-size: var(--text-sm) !important;
	}
	
	#header .language-toggle:hover {
		color: var(--color-primary) !important;
		background: var(--color-muted) !important;
		transform: translateY(-2px);
	}
	
	/* Animation for menu items */
	#header .main-nav.active ul li {
		animation: slideInUp 0.3s ease forwards;
		opacity: 0;
		transform: translateY(20px);
	}
	
	#header .main-nav.active ul li:nth-child(1) { animation-delay: 0.1s; }
	#header .main-nav.active ul li:nth-child(2) { animation-delay: 0.15s; }
	#header .main-nav.active ul li:nth-child(3) { animation-delay: 0.2s; }
	#header .main-nav.active ul li:nth-child(4) { animation-delay: 0.25s; }
	#header .main-nav.active ul li:nth-child(5) { animation-delay: 0.3s; }
	#header .main-nav.active ul li:nth-child(6) { animation-delay: 0.35s; }
	#header .main-nav.active ul li:nth-child(7) { animation-delay: 0.4s; }
}

/* Keyframe animations */
@keyframes slideInUp {
	to {
		opacity: 1;
		transform: translateY(0);
	}
}

/* Hide old menu system */
#menu,
.nav-fallback {
	display: none !important;
}

/* Desktop Navigation - Keep original layout */
@media screen and (min-width: 769px) {
	.menu-toggle,
	.menu-close {
		display: none !important;
	}
	
	#header .main-nav {
		position: static;
		transform: none;
		opacity: 1;
		visibility: visible;
		background: transparent;
		border: none;
		box-shadow: none;
	}
	
	#header .main-nav ul {
		background: transparent;
		box-shadow: none;
		border: none;
		padding: 0;
		min-width: auto;
		max-width: none;
	}
}

/* Wrapper */
#wrapper {
	min-height: 100vh;
	display: flex;
	flex-direction: column;
}

/* Main Content */
#main {
	flex: 1;
	padding: var(--space-xl) 0;
}

#main .inner {
	max-width: var(--max-width);
	margin: 0 auto;
	padding: 0 var(--space-md);
}

/* Hero Section */
.hero {
	text-align: center;
	padding: var(--space-3xl) 0 var(--space-2xl) 0;
	max-width: 800px;
	margin: 0 auto;
}

.hero h1 {
	font-size: var(--text-4xl);
	margin-bottom: var(--space-sm);
	color: var(--color-text);
}

.hero-title {
	font-size: var(--text-xl);
	color: var(--color-primary);
	font-weight: 600;
	margin-bottom: var(--space-md);
}

.hero-description {
	font-size: var(--text-lg);
	color: var(--color-text-light);
	line-height: 1.6;
	margin-bottom: var(--space-xl);
	max-width: 600px;
	margin-left: auto;
	margin-right: auto;
}

/* Navigation Cards */
.nav-cards {
	display: grid;
	grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
	gap: var(--space-lg);
	margin: var(--space-2xl) 0;
}

.nav-card {
	background: var(--color-background);
	border: 1px solid var(--color-border);
	border-radius: var(--border-radius);
	padding: var(--space-xl);
	text-align: center;
	transition: all var(--transition);
	text-decoration: none;
	color: inherit;
}

.nav-card:hover {
	transform: translateY(-2px);
	box-shadow: 0 8px 25px rgba(0, 0, 0, 0.1);
	border-color: var(--color-primary);
	color: inherit;
}

.nav-card h3 {
	color: var(--color-primary);
	margin-bottom: var(--space-sm);
	font-size: var(--text-xl);
}

.nav-card p {
	color: var(--color-text-light);
	font-size: var(--text-sm);
	line-height: 1.5;
	margin: 0;
}

/* Primary Action Buttons */
.actions-primary {
	display: flex;
	gap: var(--space-md);
	justify-content: center;
	margin: var(--space-xl) 0;
}

/* Cards */
.card {
	background: var(--color-background);
	border: 1px solid var(--color-border);
	border-radius: var(--border-radius);
	padding: var(--space-lg);
	margin-bottom: var(--space-lg);
	transition: box-shadow var(--transition);
}

.card:hover {
	box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

.card h3 {
	margin-bottom: var(--space-sm);
}

.card p {
	color: var(--color-text-light);
	margin-bottom: var(--space-md);
}

/* Project Cards */
.project-grid {
	display: grid;
	grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
	gap: var(--space-lg);
	margin: var(--space-xl) 0;
}

.project-card {
	background: var(--color-background);
	border: 1px solid var(--color-border);
	border-radius: var(--border-radius);
	padding: var(--space-lg);
	transition: all var(--transition);
}

.project-card:hover {
	box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
	transform: translateY(-1px);
}

.project-card h4 {
	color: var(--color-primary);
	margin-bottom: var(--space-sm);
	font-size: var(--text-lg);
}

.project-card .tags {
	display: flex;
	flex-wrap: wrap;
	gap: var(--space-xs);
	margin-top: var(--space-sm);
}

.tag {
	background: var(--color-muted);
	border: 1px solid var(--color-border);
	border-radius: calc(var(--border-radius) / 2);
	color: var(--color-text-light);
	font-size: var(--text-xs);
	padding: 0.25rem 0.5rem;
}

/* Publications List */
.publications-list {
	margin: var(--space-xl) 0;
}

.publications-list .card {
	margin-bottom: var(--space-md);
}

.publications-list .card h4 {
	color: var(--color-primary);
	margin-bottom: var(--space-sm);
	font-size: var(--text-lg);
	line-height: 1.4;
}

.publications-list .card p {
	margin-bottom: var(--space-xs);
	color: var(--color-text-light);
	font-size: var(--text-sm);
}

.publications-list .card p:last-child {
	margin-bottom: 0;
	font-style: italic;
}

/* Skills Section */
.skills-category {
	margin-bottom: var(--space-xl);
}

.skills-category h3 {
	color: var(--color-primary);
	margin-bottom: var(--space-md);
	font-size: var(--text-xl);
}

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

.skill-item {
	background: var(--color-muted);
	border-radius: var(--border-radius);
	padding: var(--space-sm);
	text-align: center;
}

.skill-name {
	font-weight: 600;
	margin-bottom: var(--space-xs);
}

.skill-level {
	background: var(--color-border);
	border-radius: calc(var(--border-radius) / 2);
	height: 4px;
	overflow: hidden;
}

.skill-progress {
	background: var(--color-primary);
	height: 100%;
	transition: width var(--transition);
}

/* Tools List - Ordered list format for frameworks and tools */
.tools-list {
	background: var(--color-muted);
	border-radius: var(--border-radius);
	padding: var(--space-lg);
	margin: 0;
	list-style: decimal;
	padding-left: var(--space-xl);
}

.tools-list li {
	margin-bottom: var(--space-sm);
	padding-left: var(--space-xs);
	line-height: 1.5;
}

.tools-list li:last-child {
	margin-bottom: 0;
}

.tools-list strong {
	color: var(--color-primary);
	font-weight: 600;
}

/* FAQ Sections */
.faq-section {
	margin-bottom: var(--space-2xl);
}

.faq-section h2 {
	color: var(--color-text);
	font-size: var(--text-xl);
	margin-bottom: var(--space-lg);
	border-bottom: 2px solid var(--color-border);
	padding-bottom: var(--space-sm);
}

.faq-item {
	border: 1px solid var(--color-border);
	border-radius: var(--border-radius);
	margin-bottom: var(--space-sm);
	overflow: hidden;
	transition: box-shadow var(--transition);
}

.faq-item:hover {
	box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

.faq-question {
	background: var(--color-muted);
	border: none;
	cursor: pointer;
	display: flex;
	font-family: var(--font-primary);
	font-size: var(--text-base);
	font-weight: 600;
	justify-content: space-between;
	align-items: center;
	padding: var(--space-md);
	text-align: left;
	width: 100%;
	transition: background-color var(--transition);
	color: var(--color-text);
}

.faq-question:hover {
	background: var(--color-border);
}

.faq-question:focus {
	outline: 2px solid var(--color-primary);
	outline-offset: 2px;
}

.faq-question[aria-expanded="true"] {
	background: var(--color-border);
}

.faq-icon {
	color: var(--color-primary);
	font-size: var(--text-lg);
	font-weight: bold;
	transition: transform var(--transition);
}

.faq-question[aria-expanded="true"] .faq-icon {
	transform: rotate(45deg);
}

.faq-answer {
	display: none;
	padding: var(--space-md);
	border-top: 1px solid var(--color-border);
	background: var(--color-background);
}

.faq-answer.active {
	display: block;
}

.faq-answer p {
	color: var(--color-text-light);
	line-height: 1.6;
	margin: 0 0 var(--space-sm) 0;
}

.faq-answer p:last-child {
	margin-bottom: 0;
}

.faq-answer a {
	color: var(--color-primary);
	text-decoration: none;
	transition: color var(--transition);
}

.faq-answer a:hover {
	color: var(--color-accent);
	text-decoration: underline;
}

/* Footer - Minimalist Design */
#footer {
	background: var(--color-background);
	border-top: 1px solid var(--color-border);
	color: var(--color-text-light);
	font-size: var(--text-xs);
	padding: var(--space-md) 0;
	text-align: center;
	margin-top: auto;
}

#footer .inner {
	max-width: var(--max-width);
	margin: 0 auto;
	padding: 0 var(--space-md);
}

#footer .copyright {
	list-style: none;
	margin: 0;
	padding: 0;
	display: flex;
	justify-content: center;
	align-items: center;
	gap: var(--space-sm);
	font-size: var(--text-xs);
	flex-wrap: wrap;
}

#footer .copyright li {
	margin: 0;
	padding: 0;
}

#footer .copyright a {
	color: var(--color-text-light);
	text-decoration: none;
	transition: color var(--transition);
}

#footer .copyright a:hover {
	color: var(--color-primary);
}

/* Separator between copyright items */
#footer .copyright li:not(:last-child)::after {
	content: "•";
	margin-left: var(--space-sm);
	color: var(--color-border);
}

/* Utility Classes */
.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }

.mb-0 { margin-bottom: 0; }
.mb-sm { margin-bottom: var(--space-sm); }
.mb-md { margin-bottom: var(--space-md); }
.mb-lg { margin-bottom: var(--space-lg); }
.mb-xl { margin-bottom: var(--space-xl); }

.mt-0 { margin-top: 0; }
.mt-sm { margin-top: var(--space-sm); }
.mt-md { margin-top: var(--space-md); }
.mt-lg { margin-top: var(--space-lg); }
.mt-xl { margin-top: var(--space-xl); }

.hidden { display: none; }
.visible { display: block; }

/* Responsive Images */
img {
	max-width: 100%;
	height: auto;
}

/* Accessibility */
.sr-only {
	position: absolute;
	width: 1px;
	height: 1px;
	padding: 0;
	margin: -1px;
	overflow: hidden;
	clip: rect(0, 0, 0, 0);
	white-space: nowrap;
	border: 0;
}

.skip-link {
	position: absolute;
	top: -40px;
	left: 6px;
	background: var(--color-primary);
	color: white;
	padding: 8px;
	text-decoration: none;
	z-index: 10001;
}

.skip-link:focus {
	top: 6px;
}

/* Focus States */
a:focus, button:focus, input:focus, textarea:focus, select:focus {
	outline: 2px solid var(--color-primary);
	outline-offset: 2px;
}

a:focus-visible,
button:focus-visible,
.button:focus-visible,
input:focus-visible,
textarea:focus-visible,
select:focus-visible {
	outline: 2px solid var(--color-primary);
	outline-offset: 2px;
	box-shadow: 0 0 0 4px rgba(30, 58, 138, 0.2);
}

a:focus:not(:focus-visible),
button:focus:not(:focus-visible),
.button:focus:not(:focus-visible) {
	outline: none;
}

/* Mobile Menu Enhancements for Small Screens */
@media screen and (max-width: 480px) {
	#header .main-nav {
		padding: var(--space-md) var(--space-xs);
	}
	
	#header .main-nav ul {
		gap: var(--space-xs);
		padding: var(--space-md);
		margin-top: var(--space-lg);
		margin-bottom: var(--space-lg);
		min-width: 260px;
		max-width: 95vw;
	}
	
	#header .main-nav a {
		padding: var(--space-xs) var(--space-md);
		font-size: var(--text-sm);
		min-height: 40px;
	}
	
	#header .language-toggle {
		margin-top: var(--space-xs);
		padding-top: var(--space-xs) !important;
		font-size: var(--text-xs) !important;
	}
	
	.menu-close {
		top: var(--space-md);
		right: var(--space-md);
		width: 40px;
		height: 40px;
		font-size: var(--text-lg);
	}
}

/* Responsive Design - Mobile First */
@media screen and (max-width: 768px) {
	.container {
		padding: 0 var(--space-sm);
	}
	
	#main .inner {
		padding: 0 var(--space-sm);
	}
	
	.hero {
		padding: var(--space-2xl) 0 var(--space-xl) 0;
	}
	
	.hero h1 {
		font-size: var(--text-2xl);
	}
	
	.hero-title {
		font-size: var(--text-lg);
	}
	
	.hero-description {
		font-size: var(--text-base);
	}
	
	.nav-cards {
		grid-template-columns: 1fr;
		gap: var(--space-md);
		margin: var(--space-xl) 0;
	}
	
	.nav-card {
		padding: var(--space-lg);
	}
	
	.project-grid {
		grid-template-columns: 1fr;
		gap: var(--space-md);
	}
	
	.skills-list {
		grid-template-columns: 1fr;
		gap: var(--space-sm);
	}
	
	.tools-list {
		padding: var(--space-md);
		padding-left: var(--space-lg);
	}
	
	.philosophy-values {
		grid-template-columns: 1fr;
		gap: var(--space-sm);
	}
	
	.interest-category {
		padding: var(--space-md);
		margin-bottom: var(--space-sm);
	}
	
	.actions-primary {
		flex-direction: column;
		align-items: stretch;
		gap: var(--space-sm);
	}
	
	.button {
		padding: var(--space-md) var(--space-lg);
		font-size: var(--text-base);
		min-height: 48px;
	}
	
	#header .inner {
		padding: 0 var(--space-sm);
	}
	
	#footer .copyright {
		flex-direction: column;
		gap: var(--space-xs);
		font-size: var(--text-xs);
	}
	
	input[type="text"], input[type="email"], input[type="tel"], 
	input[type="password"], textarea, select {
		min-height: 44px;
		font-size: 16px;
	}
	
	.faq-question {
		font-size: var(--text-sm);
		padding: var(--space-md);
		min-height: 48px;
	}
	
	.faq-answer {
		padding: var(--space-md);
	}
}

@media screen and (max-width: 480px) {
	.container {
		padding: 0 var(--space-xs);
	}
	
	#main .inner {
		padding: 0 var(--space-xs);
	}
	
	h1 {
		font-size: var(--text-xl);
	}
	
	.hero-title {
		font-size: var(--text-base);
	}
	
	.hero-description {
		font-size: var(--text-sm);
	}
	
	.hero {
		padding: var(--space-xl) 0;
	}
	
	.nav-card {
		padding: var(--space-md);
	}
	
	.project-card {
		padding: var(--space-md);
	}
	
	.button {
		padding: var(--space-sm) var(--space-md);
		font-size: var(--text-sm);
	}
	
	#footer .copyright {
		flex-direction: column;
		gap: var(--space-xs);
	}
}

/* Landscape orientation on mobile devices */
@media screen and (max-height: 500px) and (orientation: landscape) {
	#header .main-nav {
		align-items: flex-start;
		padding: var(--space-sm);
	}
	
	#header .main-nav ul {
		margin-top: var(--space-sm);
		margin-bottom: var(--space-sm);
		gap: var(--space-xs);
		padding: var(--space-sm);
		max-height: calc(100vh - 2rem);
	}
	
	#header .main-nav a {
		padding: var(--space-xs) var(--space-md);
		min-height: 36px;
		font-size: var(--text-sm);
	}
	
	.menu-close {
		top: var(--space-sm);
		right: var(--space-sm);
		width: 36px;
		height: 36px;
	}
}

/* Very small screens (iPhone SE, etc.) */
@media screen and (max-width: 375px) {
	#header .main-nav ul {
		min-width: 240px;
		max-width: 98vw;
		gap: 2px;
		padding: var(--space-sm);
	}
	
	#header .main-nav a {
		padding: 6px var(--space-sm);
		font-size: var(--text-xs);
		min-height: 36px;
	}
	
	#header .language-toggle {
		font-size: 10px !important;
		padding-top: 4px !important;
	}
}

/* Tablet Devices */
@media screen and (min-width: 769px) and (max-width: 1024px) {
	.container {
		padding: 0 var(--space-lg);
	}
	
	#main .inner {
		padding: 0 var(--space-lg);
	}
	
	.nav-cards {
		grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
		gap: var(--space-lg);
	}
	
	.project-grid {
		grid-template-columns: repeat(2, 1fr);
		gap: var(--space-lg);
	}
	
	.skills-list {
		grid-template-columns: repeat(2, 1fr);
		gap: var(--space-md);
	}
	
	.tools-list {
		padding: var(--space-lg);
		padding-left: var(--space-xl);
	}
	
	.philosophy-values {
		grid-template-columns: repeat(2, 1fr);
		gap: var(--space-md);
	}
	
	.actions-primary {
		flex-direction: row;
		justify-content: center;
		gap: var(--space-md);
	}
	
	.button {
		min-height: 44px;
	}
}

/* Desktop Devices */
@media screen and (min-width: 1025px) {
	.nav-cards {
		grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
		max-width: 1200px;
		margin-left: auto;
		margin-right: auto;
	}
	
	.project-grid {
		grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
	}
	
	.skills-list {
		grid-template-columns: repeat(3, 1fr);
	}
	
	.tools-list {
		padding: var(--space-lg);
		padding-left: var(--space-xl);
	}
}

/* Personal Page Styles */
.interest-category {
	background: var(--color-muted);
	border-radius: var(--border-radius);
	padding: var(--space-lg);
	margin-bottom: var(--space-md);
	border-left: 4px solid var(--color-primary);
}

.interest-category h3 {
	color: var(--color-primary);
	margin-bottom: var(--space-sm);
	font-size: var(--text-lg);
}

.interest-category p {
	color: var(--color-text-light);
	margin: 0;
	line-height: 1.5;
}

.philosophy-values {
	display: grid;
	grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
	gap: var(--space-md);
	margin-top: var(--space-lg);
}

.philosophy-values .card {
	margin-bottom: 0;
}

.philosophy-values .card h4 {
	color: var(--color-primary);
	margin-bottom: var(--space-sm);
	font-size: var(--text-lg);
}

.philosophy-values .card p {
	margin: 0;
	color: var(--color-text-light);
	line-height: 1.5;
}

/* Enhanced Interactive States */
@media (hover: hover) {
	.nav-card:hover,
	.project-card:hover {
		transform: translateY(-2px);
		box-shadow: 0 8px 25px rgba(0, 0, 0, 0.15);
	}
}

@media (hover: none) and (pointer: coarse) {
	.nav-card:hover,
	.project-card:hover {
		transform: none;
		box-shadow: none;
	}
	
	.button {
		min-height: 48px;
		padding: var(--space-md) var(--space-lg);
	}
	
	.nav-cards {
		gap: var(--space-lg);
	}
}

/* High Contrast Support */
@media (prefers-contrast: high) {
	:root {
		--color-text: #000000;
		--color-background: #ffffff;
		--color-border: #000000;
	}
	
	.button {
		border: 2px solid currentColor;
	}
	
	.nav-card,
	.project-card {
		border-width: 2px;
	}
}

/* Reduced Motion */
@media (prefers-reduced-motion: reduce) {
	*, *:before, *:after {
		animation-duration: 0.01ms !important;
		animation-iteration-count: 1 !important;
		transition-duration: 0.01ms !important;
	}
	
	.nav-card:hover,
	.project-card:hover,
	.button:hover {
		transform: none;
	}
}

/* Print Styles */
@media print {
	* {
		background: transparent !important;
		color: black !important;
		box-shadow: none !important;
		text-shadow: none !important;
	}
	
	a, a:visited {
		text-decoration: underline;
	}
	
	#header, #footer, .menu-toggle {
		display: none;
	}
	
	.nav-card, .project-card {
		break-inside: avoid;
		border: 1px solid #000;
	}
}
/* Cont
act Page Styles */
.contact-grid {
	display: grid;
	grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
	gap: var(--space-lg);
	margin: var(--space-lg) 0;
}

.contact-item {
	background: var(--color-muted);
	border: 1px solid var(--color-border);
	border-radius: var(--border-radius);
	padding: var(--space-lg);
}

.contact-item h3 {
	color: var(--color-primary);
	font-size: var(--text-lg);
	margin-bottom: var(--space-sm);
}

.contact-item p {
	margin-bottom: 0;
	line-height: 1.5;
}

.contact-item a {
	font-weight: 500;
}

/* Contact Form Styles */
.contact-form {
	background: var(--color-muted);
	border: 1px solid var(--color-border);
	border-radius: var(--border-radius);
	padding: var(--space-xl);
	margin: var(--space-lg) 0;
}

.form-row {
	display: grid;
	grid-template-columns: 1fr 1fr;
	gap: var(--space-md);
}

.form-group {
	margin-bottom: var(--space-md);
}

.form-group label {
	display: block;
	font-weight: 500;
	margin-bottom: var(--space-xs);
	color: var(--color-text);
}

.form-group input,
.form-group textarea {
	margin-bottom: 0;
}

/* Social Links */
.social-links {
	display: grid;
	grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
	gap: var(--space-md);
	margin: var(--space-lg) 0;
}

.social-link {
	display: flex;
	align-items: center;
	background: var(--color-muted);
	border: 1px solid var(--color-border);
	border-radius: var(--border-radius);
	padding: var(--space-md);
	text-decoration: none;
	transition: all var(--transition);
}

.social-link:hover {
	background: var(--color-primary);
	color: white;
	transform: translateY(-2px);
	box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

.social-icon {
	font-size: var(--text-xl);
	margin-right: var(--space-sm);
}

.social-text {
	font-weight: 500;
}

/* Notice Section */
.notice {
	background: #fef3cd;
	border: 1px solid #fde047;
	border-radius: var(--border-radius);
	padding: var(--space-lg);
	margin: var(--space-xl) 0;
}

.notice h3 {
	color: #92400e;
	margin-bottom: var(--space-sm);
}

.notice p {
	color: #92400e;
	margin-bottom: 0;
}

/* Mobile Responsive Adjustments */
@media screen and (max-width: 768px) {
	.contact-grid {
		grid-template-columns: 1fr;
		gap: var(--space-md);
	}
	
	.form-row {
		grid-template-columns: 1fr;
		gap: var(--space-sm);
	}
	
	.contact-form {
		padding: var(--space-lg);
	}
	
	.social-links {
		grid-template-columns: 1fr;
		gap: var(--space-sm);
	}
}

@media screen and (max-width: 480px) {
	.contact-item,
	.contact-form {
		padding: var(--space-md);
	}
	
	.social-link {
		padding: var(--space-sm);
	}
}/* Com
ing Soon Section Styles */
.coming-soon {
	margin-top: var(--space-xl);
	text-align: center;
}

.coming-soon h2 {
	color: var(--color-primary);
	margin-bottom: var(--space-md);
	font-family: var(--font-heading);
}

.nav-cards.placeholder {
	display: grid;
	grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
	gap: var(--space-md);
	margin: var(--space-lg) 0;
}

.nav-cards.placeholder .nav-card {
	position: relative;
	background: var(--color-background);
	border: 2px dashed var(--color-border);
	border-radius: 8px;
	padding: var(--space-md);
	text-decoration: none;
	color: var(--color-text-light);
	transition: all 0.3s ease;
	cursor: default;
}

.nav-cards.placeholder .nav-card:hover {
	border-color: var(--color-primary);
	transform: translateY(-2px);
}

.nav-cards.placeholder .nav-card h3 {
	color: var(--color-text);
	margin-bottom: var(--space-sm);
	font-size: var(--text-lg);
}

.nav-cards.placeholder .nav-card p {
	margin-bottom: var(--space-sm);
	font-size: var(--text-sm);
	line-height: 1.5;
}

.nav-cards.placeholder .nav-card .status {
	display: inline-block;
	background: var(--color-accent);
	color: white;
	padding: 0.25rem 0.75rem;
	border-radius: 12px;
	font-size: var(--text-sm);
	font-weight: 500;
}

.coming-soon .note {
	margin-top: var(--space-lg);
	font-style: italic;
	color: var(--color-text-light);
}

.coming-soon .note a {
	color: var(--color-primary);
	text-decoration: none;
	font-weight: 500;
}

.coming-soon .note a:hover {
	text-decoration: underline;
	margin-bottom: var(--space-xs);
	color: var(--color-text);
}

.form-group input,
.form-group textarea {
	width: 100%;
	padding: var(--space-sm);
	border: 1px solid var(--color-border);
	border-radius: var(--border-radius);
	font-family: var(--font-primary);
	font-size: var(--text-base);
	background: var(--color-background);
	color: var(--color-text);
	transition: border-color 0.2s ease;
}

.form-group input:focus,
.form-group textarea:focus {
	outline: none;
	border-color: var(--color-primary);
	box-shadow: 0 0 0 2px rgba(30, 58, 138, 0.1);
}

.form-group textarea {
	resize: vertical;
	min-height: 120px;
}

@media (max-width: 768px) {
	.form-row {
		grid-template-columns: 1fr;
	}
}



/* Social Links */
.social-links {
	display: flex;
	gap: var(--space-md);
	flex-wrap: wrap;
	margin: var(--space-lg) 0;
}

.social-link {
	display: inline-flex;
	align-items: center;
	padding: var(--space-sm) var(--space-md);
	background: var(--color-muted);
	border: 1px solid var(--color-border);
	border-radius: var(--border-radius);
	text-decoration: none;
	color: var(--color-text);
	font-weight: 500;
	transition: all 0.2s ease;
}

.social-link:hover {
	background: var(--color-primary);
	color: var(--color-background);
	border-color: var(--color-primary);
	transform: translateY(-1px);
}

/* Accessibility Improvements */
.sr-only {
	position: absolute;
	width: 1px;
	height: 1px;
	padding: 0;
	margin: -1px;
	overflow: hidden;
	clip: rect(0, 0, 0, 0);
	white-space: nowrap;
	border: 0;
}

.skip-link {
	position: absolute;
	top: -40px;
	left: 6px;
	background: var(--color-primary);
	color: var(--color-background);
	padding: 8px;
	text-decoration: none;
	border-radius: var(--border-radius);
	z-index: 1000;
}

.skip-link:focus {
	top: 6px;
}

/* Focus Indicators */
a:focus,
button:focus,
input:focus,
textarea:focus {
	outline: 2px solid var(--color-primary);
	outline-offset: 2px;
}

/* High Contrast Mode Support */
@media (prefers-contrast: high) {
	.faq-question {
		border: 2px solid currentColor;
	}
	
	.social-link {
		border: 2px solid currentColor;
	}
}
/* E
ducation Background Styles */
.education-tabs {
	display: flex;
	flex-direction: column;
	gap: var(--space-lg);
	margin: var(--space-xl) 0;
}

.education-tab {
	background: var(--color-background);
	border: 1px solid var(--color-border);
	border-radius: var(--border-radius);
	padding: var(--space-lg);
	transition: all var(--transition);
}

.education-tab:hover {
	box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
	transform: translateY(-1px);
}

.education-header {
	display: flex;
	align-items: center;
	gap: var(--space-md);
	margin-bottom: var(--space-md);
}

.university-logo {
	flex-shrink: 0;
	width: 48px;
	height: 48px;
	border-radius: var(--border-radius);
	overflow: hidden;
	border: 1px solid var(--color-border);
	display: flex;
	align-items: center;
	justify-content: center;
	background: var(--color-muted);
}

.university-logo img {
	width: 100%;
	height: 100%;
	object-fit: contain;
}

.education-info h3 {
	color: var(--color-primary);
	margin-bottom: var(--space-xs);
	font-size: var(--text-lg);
}

.education-info p {
	margin-bottom: var(--space-xs);
	color: var(--color-text-light);
	font-size: var(--text-sm);
}

.education-info p:last-child {
	margin-bottom: 0;
}

.education-details {
	color: var(--color-text-light);
	line-height: 1.6;
}

/* Internship Experience Styles */
.internship-tabs {
	display: flex;
	flex-direction: column;
	gap: var(--space-lg);
	margin: var(--space-xl) 0;
}

.internship-tab {
	background: var(--color-background);
	border: 1px solid var(--color-border);
	border-radius: var(--border-radius);
	padding: var(--space-lg);
	transition: all var(--transition);
}

.internship-tab:hover {
	box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
	transform: translateY(-1px);
}

.internship-header {
	display: flex;
	align-items: center;
	gap: var(--space-md);
	margin-bottom: var(--space-md);
}

.company-logo {
	flex-shrink: 0;
	width: 48px;
	height: 48px;
	border-radius: var(--border-radius);
	overflow: hidden;
	border: 1px solid var(--color-border);
	display: flex;
	align-items: center;
	justify-content: center;
	background: var(--color-muted);
}

.logo-placeholder {
	font-size: var(--text-xl);
	color: var(--color-text-light);
}

.internship-info h3 {
	color: var(--color-primary);
	margin-bottom: var(--space-xs);
	font-size: var(--text-lg);
}

.internship-info p {
	margin-bottom: var(--space-xs);
	color: var(--color-text-light);
	font-size: var(--text-sm);
}

.internship-info p:last-child {
	margin-bottom: 0;
}

.internship-details {
	color: var(--color-text-light);
	line-height: 1.6;
}

/* Teaching Experience Styles */
.teaching-experience {
	display: flex;
	flex-direction: column;
	gap: var(--space-lg);
	margin: var(--space-xl) 0;
}

.teaching-item {
	display: flex;
	align-items: flex-start;
	gap: var(--space-md);
	background: var(--color-muted);
	border-radius: var(--border-radius);
	padding: var(--space-lg);
	border-left: 4px solid var(--color-primary);
	transition: all var(--transition);
}

.teaching-item:hover {
	box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
	transform: translateX(2px);
}

.teaching-icon {
	flex-shrink: 0;
	width: 40px;
	height: 40px;
	border-radius: 50%;
	background: var(--color-primary);
	color: white;
	display: flex;
	align-items: center;
	justify-content: center;
	font-size: var(--text-lg);
}

.teaching-content h3 {
	color: var(--color-primary);
	margin-bottom: var(--space-xs);
	font-size: var(--text-lg);
}

.teaching-content p {
	margin-bottom: var(--space-xs);
	color: var(--color-text-light);
	line-height: 1.5;
}

.teaching-content p:last-child {
	margin-bottom: 0;
}

/* Personal Interests Styles */
.interests-grid {
	display: grid;
	grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
	gap: var(--space-lg);
	margin: var(--space-xl) 0;
}

.interest-item {
	display: flex;
	align-items: flex-start;
	gap: var(--space-md);
	background: var(--color-muted);
	border-radius: var(--border-radius);
	padding: var(--space-lg);
	border-left: 4px solid var(--color-primary);
	transition: all var(--transition);
}

.interest-item:hover {
	box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
	transform: translateY(-2px);
}

.interest-icon {
	flex-shrink: 0;
	width: 48px;
	height: 48px;
	border-radius: 50%;
	background: var(--color-primary);
	color: white;
	display: flex;
	align-items: center;
	justify-content: center;
	font-size: var(--text-xl);
}

.interest-content h3 {
	color: var(--color-primary);
	margin-bottom: var(--space-xs);
	font-size: var(--text-lg);
}

.interest-content p {
	margin-bottom: var(--space-xs);
	color: var(--color-text-light);
	line-height: 1.6;
}

.interest-content p:last-child {
	margin-bottom: 0;
}

/* Mobile Responsive Styles for Personal Page */
@media screen and (max-width: 768px) {
	.education-header,
	.internship-header {
		flex-direction: column;
		align-items: flex-start;
		gap: var(--space-sm);
		text-align: center;
	}
	
	.education-header {
		align-items: center;
	}
	
	.internship-header {
		align-items: center;
	}
	
	.teaching-item,
	.interest-item {
		flex-direction: column;
		align-items: center;
		text-align: center;
		gap: var(--space-sm);
	}
	
	.interests-grid {
		grid-template-columns: 1fr;
		gap: var(--space-md);
	}
	
	.teaching-experience {
		gap: var(--space-md);
	}
	
	.education-tabs,
	.internship-tabs {
		gap: var(--space-md);
	}
}

@media screen and (max-width: 480px) {
	.education-tab,
	.internship-tab,
	.teaching-item,
	.interest-item {
		padding: var(--space-md);
	}
	
	.university-logo,
	.company-logo {
		width: 40px;
		height: 40px;
	}
	
	.teaching-icon,
	.interest-icon {
		width: 36px;
		height: 36px;
		font-size: var(--text-base);
	}
}