/* ============================================
   UZJS.uz — Uzbek Journal of Science
   Design System & Styles
   ============================================ */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&family=Playfair+Display:ital,wght@0,400;0,600;0,700;1,400&display=swap');

:root {
  --primary: #0a1628;
  --primary-light: #162240;
  --primary-lighter: #1e3054;
  --accent: #2563eb;
  --accent-light: #3b82f6;
  --accent-dark: #1d4ed8;
  --gold: #d4a843;
  --gold-light: #e8c76a;
  --success: #10b981;
  --warning: #f59e0b;
  --danger: #ef4444;
  --white: #ffffff;
  --gray-50: #f8fafc; --gray-100: #f1f5f9; --gray-200: #e2e8f0;
  --gray-300: #cbd5e1; --gray-400: #94a3b8; --gray-500: #64748b;
  --gray-600: #475569; --gray-700: #334155; --gray-800: #1e293b; --gray-900: #0f172a;
  --text-primary: #1e293b; --text-secondary: #64748b; --text-muted: #94a3b8;
  --bg-body: #f8fafc; --bg-card: #ffffff; --border-color: #e2e8f0;
  --font-body: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-heading: 'Playfair Display', Georgia, serif;
  --space-xs: 0.25rem; --space-sm: 0.5rem; --space-md: 1rem; --space-lg: 1.5rem;
  --space-xl: 2rem; --space-2xl: 3rem; --space-3xl: 4rem; --space-4xl: 6rem;
  --container-max: 1280px; --container-narrow: 900px;
  --radius-sm: 6px; --radius-md: 10px; --radius-lg: 16px; --radius-xl: 24px;
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.06), 0 1px 2px rgba(0,0,0,0.04);
  --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.07), 0 2px 4px -1px rgba(0,0,0,0.04);
  --shadow-lg: 0 10px 25px -3px rgba(0,0,0,0.08), 0 4px 6px -2px rgba(0,0,0,0.03);
  --shadow-xl: 0 20px 50px -12px rgba(0,0,0,0.15);
  --shadow-card: 0 1px 3px rgba(0,0,0,0.04), 0 6px 16px rgba(0,0,0,0.04);
  --transition-fast: 150ms ease; --transition-base: 250ms ease; --transition-slow: 400ms ease;
}

*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; font-size: 16px; }
body { font-family: var(--font-body); color: var(--text-primary); background: var(--bg-body); line-height: 1.7; -webkit-font-smoothing: antialiased; overflow-x: hidden; }
a { color: var(--accent); text-decoration: none; transition: color var(--transition-fast); }
a:hover { color: var(--accent-dark); }
img { max-width: 100%; height: auto; display: block; }
ul, ol { list-style: none; }
h1, h2, h3, h4, h5, h6 { font-family: var(--font-heading); color: var(--primary); line-height: 1.3; font-weight: 700; }
h1 { font-size: 2.75rem; } h2 { font-size: 2rem; } h3 { font-size: 1.5rem; } h4 { font-size: 1.25rem; }
p { margin-bottom: var(--space-md); }

.container { width: 100%; max-width: var(--container-max); margin: 0 auto; padding: 0 var(--space-xl); }
.container--narrow { max-width: var(--container-narrow); }
.section { padding: var(--space-4xl) 0; }
.section--dark { background: var(--primary); color: var(--white); }
.section--gray { background: var(--gray-100); }
.grid { display: grid; gap: var(--space-xl); }
.grid--2 { grid-template-columns: repeat(2, 1fr); }
.grid--3 { grid-template-columns: repeat(3, 1fr); }
.grid--4 { grid-template-columns: repeat(4, 1fr); }
.flex { display: flex; align-items: center; }
.flex--between { justify-content: space-between; }
.flex--center { justify-content: center; }
.flex--gap { gap: var(--space-md); }

/* TOP BAR */
.top-bar { background: var(--primary); color: var(--gray-300); font-size: 0.8rem; padding: var(--space-xs) 0; border-bottom: 1px solid rgba(255,255,255,0.08); }
.top-bar .container { display: flex; justify-content: space-between; align-items: center; }
.top-bar a { color: var(--gray-300); } .top-bar a:hover { color: var(--white); }
.top-bar__links { display: flex; gap: var(--space-lg); align-items: center; }
.lang-switcher { display: flex; gap: 2px; background: rgba(255,255,255,0.06); border-radius: var(--radius-sm); padding: 2px; }
.lang-switcher button { background: transparent; border: none; color: var(--gray-400); font-size: 0.75rem; font-weight: 600; padding: 4px 10px; border-radius: 4px; cursor: pointer; transition: all var(--transition-fast); font-family: var(--font-body); letter-spacing: 0.5px; }
.lang-switcher button:hover { color: var(--white); background: rgba(255,255,255,0.08); }
.lang-switcher button.active { background: var(--accent); color: var(--white); }

/* HEADER */
.header { background: var(--white); border-bottom: 1px solid var(--border-color); position: sticky; top: 0; z-index: 1000; transition: box-shadow var(--transition-base); }
.header.scrolled { box-shadow: var(--shadow-lg); }
.header .container { display: flex; justify-content: space-between; align-items: center; padding-top: var(--space-md); padding-bottom: var(--space-md); }
.logo { display: flex; align-items: center; gap: var(--space-md); text-decoration: none; }
.logo__icon { width: 48px; height: 48px; background: linear-gradient(135deg, var(--accent), var(--accent-dark)); border-radius: var(--radius-md); display: flex; align-items: center; justify-content: center; color: white; font-family: var(--font-heading); font-weight: 700; font-size: 1.2rem; flex-shrink: 0; }
.logo__text { display: flex; flex-direction: column; }
.logo__title { font-family: var(--font-heading); font-size: 1.15rem; font-weight: 700; color: var(--primary); line-height: 1.2; }
.logo__subtitle { font-size: 0.72rem; color: var(--text-secondary); text-transform: uppercase; letter-spacing: 1.5px; font-weight: 500; }
.nav { display: flex; align-items: center; gap: var(--space-xs); }
.nav a { color: var(--text-primary); font-weight: 500; font-size: 0.9rem; padding: var(--space-sm) var(--space-md); border-radius: var(--radius-sm); transition: all var(--transition-fast); }
.nav a:hover, .nav a.active { color: var(--accent); background: rgba(37,99,235,0.06); }
.nav__dropdown { position: relative; }
.nav__dropdown-trigger { display: flex; align-items: center; gap: 4px; }
.nav__dropdown-trigger::after { content: ''; width: 0; height: 0; border-left: 4px solid transparent; border-right: 4px solid transparent; border-top: 4px solid currentColor; transition: transform var(--transition-fast); }
.nav__dropdown:hover .nav__dropdown-trigger::after { transform: rotate(180deg); }
.nav__dropdown-menu { position: absolute; top: 100%; left: 0; background: var(--white); border: 1px solid var(--border-color); border-radius: var(--radius-md); box-shadow: var(--shadow-lg); min-width: 220px; padding: var(--space-sm); opacity: 0; visibility: hidden; transform: translateY(8px); transition: all var(--transition-base); z-index: 100; }
.nav__dropdown:hover .nav__dropdown-menu { opacity: 1; visibility: visible; transform: translateY(0); }
.nav__dropdown-menu a { display: block; padding: var(--space-sm) var(--space-md); border-radius: var(--radius-sm); font-size: 0.88rem; }
.menu-toggle { display: none; flex-direction: column; gap: 5px; background: none; border: none; cursor: pointer; padding: 8px; }
.menu-toggle span { width: 24px; height: 2px; background: var(--primary); border-radius: 2px; transition: all var(--transition-base); }