/* Variables */
:root {
    --bg-color: #0b1121;
    --card-bg: #162032;
    --text-primary: #ffffff;
    --text-secondary: #94a3b8;
    --accent-blue: #93c5fd;
    --accent-green: #10b981;
    --accent-purple: #6366f1;
    --font-family: 'Inter', sans-serif;
}

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

body {
    background-color: var(--bg-color);
    color: var(--text-primary);
    font-family: var(--font-family);
    line-height: 1.6;
    overflow-x: hidden;
}

a { text-decoration: none; color: inherit; }
h1, h2, h3 { font-weight: 800; line-height: 1.2; }

/* FIX UX : STICKY HEADER */
header {
    position: sticky;
    top: 0;
    width: 100%;
    background-color: rgba(11, 17, 33, 0.95);
    backdrop-filter: blur(8px);
    z-index: 1000;
    border-bottom: 1px solid rgba(255,255,255,0.05);
}

.header-inner {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 5%;
    max-width: 1200px;
    margin: auto;
}

/* GRADIENT LOGO FIX (Blue to Green) */
.logo a {
    font-size: 1.25rem;
    font-weight: 700;
    line-height: 1.1;
    display: block;
    background: linear-gradient(90deg, var(--accent-blue) 0%, var(--accent-green) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    color: transparent;
}

nav ul {
    display: flex;
    list-style: none;
    gap: 2rem;
}

nav a {
    font-size: 0.95rem;
    font-weight: 600;
    transition: color 0.3s ease;
}

nav a:hover, nav a.active { color: var(--accent-green); }

/* Burger Menu */
.burger {
    display: none;
    cursor: pointer;
    z-index: 1001;
}

.burger div {
    width: 25px;
    height: 3px;
    background-color: var(--text-primary);
    margin: 5px;
    transition: all 0.3s ease;
}

/* Hero Section */
.hero { text-align: center; padding: 5rem 5% 4rem; max-width: 800px; margin: auto; }
.hero h1 { font-size: clamp(2.5rem, 5vw, 4rem); margin-bottom: 1.5rem; }
.hero p { color: var(--text-secondary); font-size: 1.1rem; margin-bottom: 2.5rem; }

.btn {
    display: inline-block;
    background-color: var(--accent-purple);
    color: white;
    padding: 0.8rem 2rem;
    border-radius: 8px;
    font-weight: 600;
    transition: background-color 0.3s ease;
}
.btn:hover { background-color: #4f46e5; }

/* Articles Section */
.publications { max-width: 1200px; margin: auto; padding: 2rem 5% 5rem; }
.publications h2 { font-size: 2rem; margin-bottom: 0.5rem; }
.section-subtitle { color: var(--text-secondary); margin-bottom: 3rem; }

/* Cards */
.card {
    background-color: var(--card-bg);
    border-radius: 12px;
    padding: 2rem;
    transition: transform 0.3s ease;
    border: 1px solid rgba(255,255,255,0.05);
}
.card:hover { transform: translateY(-5px); }

.tag { font-size: 0.75rem; font-weight: 700; color: var(--accent-green); letter-spacing: 1px; margin-bottom: 1rem; }
.card h3 { font-size: 1.4rem; margin-bottom: 1rem; }
.card h3 a:hover { text-decoration: underline; }
.card p { color: var(--text-secondary); font-size: 0.95rem; margin-bottom: 1.5rem; }
.read-more { font-size: 0.9rem; font-weight: 600; color: var(--accent-blue); }
.read-more:hover { color: white; }

/* Featured Card */
.featured-card { margin-bottom: 2rem; background: linear-gradient(145deg, #162032, #1a263c); border-left: 4px solid var(--accent-purple); }
.featured-tag { color: var(--accent-purple); }
.featured-card h3 { font-size: 2rem; }

/* Grid Layout */
.grid-articles { display: grid; grid-template-columns: repeat(auto-fit, minmax(300px, 1fr)); gap: 2rem; }

/* Article Content Layout */
.article-page { padding: 2rem 5% 5rem; }
.content-wrapper { max-width: 800px; margin: auto; }
.content-wrapper h1 { font-size: clamp(2rem, 4vw, 3rem); margin: 1rem 0; }
.author-date { color: var(--text-secondary); margin-bottom: 3rem; font-size: 0.9rem; }
.article-body h2 { margin: 2.5rem 0 1rem; font-size: 1.8rem; color: var(--accent-blue); }
.article-body h3 { margin: 1.5rem 0 0.5rem; font-size: 1.3rem; }
.article-body p { color: #cbd5e1; margin-bottom: 1.2rem; font-size: 1.1rem; }
.article-body ul { color: #cbd5e1; margin-bottom: 1.5rem; padding-left: 1.5rem; }
.article-body li { margin-bottom: 0.5rem; }
.highlight-box { background-color: var(--card-bg); border-left: 4px solid var(--accent-green); padding: 1.5rem; margin: 2rem 0; font-size: 1.2rem; font-style: italic; }
.back-link { display: inline-block; margin-top: 3rem; color: var(--accent-blue); font-weight: 600; }
footer { text-align: center; padding: 2rem; color: var(--text-secondary); border-top: 1px solid rgba(255,255,255,0.05); }

/* =========================================
   RESPONSIVE WEBDESIGN & BURGER MENU
   ========================================= */
@media screen and (max-width: 768px) {
    nav ul {
        position: fixed;
        right: -100%;
        top: 70px;
        height: calc(100vh - 70px);
        width: 100%;
        max-width: 300px;
        background-color: #0f172a;
        flex-direction: column;
        align-items: center;
        justify-content: flex-start;
        padding-top: 3rem;
        gap: 2rem;
        transition: right 0.4s ease-in-out;
        box-shadow: -5px 0 15px rgba(0,0,0,0.5);
    }
    nav ul.nav-active { right: 0; }
    nav ul li { width: 100%; text-align: center; }
    nav ul li a { display: block; padding: 1rem; font-size: 1.2rem; }
    
    .burger { display: block; }
    .toggle .line1 { transform: rotate(-45deg) translate(-5px, 6px); }
    .toggle .line2 { opacity: 0; }
    .toggle .line3 { transform: rotate(45deg) translate(-5px, -6px); }
    
    .hero h1 { margin-top: 2rem; }
    .featured-card h3 { font-size: 1.5rem; }
}