/* ===========================
   Enhanced CSS (conflict-safe)
   =========================== */

/* Optional: keep everything scoped by adding a wrapper class if you ever need it.
   Example: prefix your page with .kb and change :root -> .kb { ... }.
   For now we keep :root to avoid HTML changes. */

@layer reset, base, layout, components, utilities;

@layer reset {
  *, *::before, *::after { box-sizing: border-box; }
  * { margin: 0; padding: 0; }
  html:focus-within { scroll-behavior: smooth; }
  img, svg, video, canvas { display: block; max-width: 100%; }
  input, button, textarea, select { font: inherit; color: inherit; }
  a { color: inherit; }
  ul, ol { padding-left: 1.25rem; }
}

@layer base {
  :root {
    /* Brand */
    --primary: #3a86ff;
    --primary-dark: #2563eb;
    --secondary: #8b5cf6;
    --accent: #ff6b6b;

    /* Neutrals */
    --darker: #0a0e1a;
    --dark: #0f172a;
    --card-bg: #1e293b;
    --card-border: #334155;
    --light: #f8fafc;
    --gray: #94a3b8;
    --gray-light: #e2e8f0;

    /* Layout */
    --container: 1200px;
    --radius: 14px;
    --radius-sm: 10px;
    --radius-lg: 18px;

    /* Spacing */
    --space-1: 6px;
    --space-2: 10px;
    --space-3: 14px;
    --space-4: 18px;
    --space-5: 24px;
    --space-6: 32px;
    --space-7: 40px;
    --space-8: 56px;

    /* Typography */
    --fs-1: clamp(0.85rem, 0.82rem + 0.2vw, 0.95rem);
    --fs-2: clamp(0.95rem, 0.9rem + 0.25vw, 1.05rem);
    --fs-3: clamp(1.1rem, 1.02rem + 0.35vw, 1.25rem);
    --fs-4: clamp(1.4rem, 1.15rem + 0.9vw, 2rem);
    --fs-5: clamp(2rem, 1.4rem + 2vw, 3.2rem);

    /* Motion */
    --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
    --ease-soft: cubic-bezier(0.2, 0.8, 0.2, 1);
    --dur-1: 140ms;
    --dur-2: 220ms;
    --dur-3: 320ms;

    /* Elevation */
    --shadow-sm: 0 8px 18px rgba(0, 0, 0, 0.22);
    --shadow: 0 14px 30px rgba(0, 0, 0, 0.28);
    --shadow-lg: 0 22px 60px rgba(0, 0, 0, 0.35);

    /* Effects */
    --glass: rgba(15, 23, 42, 0.62);
    --glass-strong: rgba(15, 23, 42, 0.78);
    --outline: 0 0 0 3px rgba(58, 134, 255, 0.35);

    /* Gradient helpers */
    --grad-brand: linear-gradient(90deg, var(--primary), var(--secondary));
    --grad-bg: linear-gradient(135deg, var(--darker) 0%, var(--dark) 100%);
  }

  body {
    font-family: ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto, Ubuntu, Cantarell,
      "Noto Sans", Arial, "Apple Color Emoji", "Segoe UI Emoji";
    background: var(--grad-bg);
    color: var(--light);
    line-height: 1.6;
    min-height: 100svh;
    text-rendering: optimizeLegibility;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
  }

  ::selection {
    background: rgba(58, 134, 255, 0.35);
    color: var(--light);
  }

  /* Accessible focus */
  :focus { outline: none; }
  :focus-visible { box-shadow: var(--outline); border-radius: 10px; }

  @media (prefers-reduced-motion: reduce) {
    html:focus-within { scroll-behavior: auto; }
    *, *::before, *::after { transition: none !important; animation: none !important; }
  }
}

@layer layout {
  .container {
    max-width: var(--container);
    margin: 0 auto;
    padding: 0 clamp(16px, 3vw, 24px);
  }

  header {
    background: var(--glass);
    border-bottom: 1px solid rgba(51, 65, 85, 0.9);
    position: sticky;
    top: 0;
    z-index: 100;
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
  }

  .header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 14px 0;
    gap: 14px;
  }

  @media (max-width: 768px) {
    .header-content { flex-direction: column; align-items: stretch; }
  }

  nav ul {
    display: flex;
    list-style: none;
    gap: 18px;
    flex-wrap: wrap;
    justify-content: center;
    padding-left: 0; /* since we reset lists */
  }

  .main-content { padding: var(--space-7) 0; }

  footer {
    background: rgba(10, 14, 26, 0.85);
    border-top: 1px solid rgba(51, 65, 85, 0.9);
    padding: var(--space-8) 0;
    margin-top: var(--space-8);
  }
}

@layer components {
  /* Logo */
  .logo {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    font-size: 1.35rem;
    font-weight: 760;
    letter-spacing: 0.2px;
    text-decoration: none;
    color: var(--light);
    user-select: none;
  }

  .logo-icon { color: var(--primary); filter: drop-shadow(0 8px 18px rgba(58,134,255,0.25)); }

  /* Nav */
  nav a {
    color: rgba(148, 163, 184, 0.95);
    text-decoration: none;
    font-weight: 600;
    font-size: var(--fs-1);
    padding: 10px 12px;
    border-radius: 999px;
    transition: transform var(--dur-2) var(--ease-out),
                background var(--dur-2) var(--ease-out),
                color var(--dur-2) var(--ease-out);
  }

  nav a:hover {
    color: var(--light);
    background: rgba(58, 134, 255, 0.12);
    transform: translateY(-1px);
  }

  nav a.active {
    color: var(--light);
    background: rgba(58, 134, 255, 0.16);
    border: 1px solid rgba(58, 134, 255, 0.24);
  }

  /* Hero */
  .hero {
    text-align: center;
    padding: clamp(44px, 6vw, 80px) 0 clamp(28px, 3.5vw, 44px);
    background:
      radial-gradient(circle at top right, rgba(59, 134, 255, 0.18), transparent 420px),
      radial-gradient(circle at bottom left, rgba(139, 92, 246, 0.18), transparent 420px);
  }

  .hero h1 {
    font-size: var(--fs-5);
    margin-bottom: 14px;
    line-height: 1.12;
    letter-spacing: -0.8px;
    background: var(--grad-brand);
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
    filter: drop-shadow(0 16px 36px rgba(0,0,0,0.25));
  }

  .hero p {
    font-size: var(--fs-2);
    color: rgba(148, 163, 184, 0.95);
    max-width: 820px;
    margin: 0 auto 28px;
  }

  /* Search */
  .search-container {
    max-width: 640px;
    margin: 0 auto;
    position: relative;
  }

  .search-box {
    width: 100%;
    padding: 16px 18px;
    padding-left: 52px;
    border-radius: 999px;
    border: 1px solid rgba(51, 65, 85, 0.9);
    background: rgba(30, 41, 59, 0.55);
    color: var(--light);
    font-size: var(--fs-2);
    box-shadow: 0 10px 35px rgba(0,0,0,0.22);
    transition: border var(--dur-2) var(--ease-out),
                box-shadow var(--dur-2) var(--ease-out),
                background var(--dur-2) var(--ease-out),
                transform var(--dur-2) var(--ease-out);
  }

  .search-box::placeholder { color: rgba(148, 163, 184, 0.75); }

  .search-box:focus {
    border-color: rgba(58, 134, 255, 0.65);
    box-shadow: var(--outline), 0 14px 50px rgba(0,0,0,0.32);
    background: rgba(30, 41, 59, 0.72);
    transform: translateY(-1px);
  }

  .search-icon {
    position: absolute;
    left: 18px;
    top: 50%;
    transform: translateY(-50%);
    color: rgba(148, 163, 184, 0.9);
    pointer-events: none;
  }

  /* Titles */
  .section-title {
    font-size: var(--fs-4);
    margin-bottom: 26px;
    position: relative;
    padding-bottom: 14px;
    letter-spacing: -0.2px;
  }

  .section-title::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 64px;
    height: 4px;
    background: var(--grad-brand);
    border-radius: 3px;
    box-shadow: 0 8px 22px rgba(58, 134, 255, 0.18);
  }

  /* Grids */
  .categories-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(min(280px, 100%), 1fr));
    gap: 18px;
    margin-bottom: 46px;
  }

  .articles-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(min(350px, 100%), 1fr));
    gap: 18px;
  }

  /* Shared card base */
  .category-card,
  .article-card,
  .article-wrap {
    background: linear-gradient(180deg, rgba(30, 41, 59, 0.92), rgba(30, 41, 59, 0.72));
    border: 1px solid rgba(51, 65, 85, 0.9);
    border-radius: var(--radius);
    box-shadow: var(--shadow-sm);
  }

  .category-card,
  .article-card {
    text-decoration: none;
    color: inherit;
    display: block;
    transition: transform var(--dur-3) var(--ease-out),
                border-color var(--dur-2) var(--ease-out),
                box-shadow var(--dur-3) var(--ease-out),
                background var(--dur-3) var(--ease-out);
    position: relative;
    overflow: hidden;
  }

  /* Card shine */
  .category-card::before,
  .article-card::before {
    content: "";
    position: absolute;
    inset: -2px;
    background: radial-gradient(800px 140px at 10% 0%, rgba(58,134,255,0.18), transparent 55%);
    opacity: 0;
    transition: opacity var(--dur-3) var(--ease-out);
    pointer-events: none;
  }

  .category-card:hover,
  .article-card:hover {
    transform: translateY(-5px);
    border-color: rgba(58, 134, 255, 0.55);
    box-shadow: var(--shadow);
  }

  .category-card:hover::before,
  .article-card:hover::before { opacity: 1; }

  .category-card:active,
  .article-card:active { transform: translateY(-2px); }

  /* Category */
  .category-card { padding: 24px; }
  .category-icon {
    font-size: 34px;
    margin-bottom: 14px;
    color: var(--primary);
    filter: drop-shadow(0 10px 22px rgba(58,134,255,0.22));
  }
  .category-title { font-size: 1.2rem; margin-bottom: 8px; letter-spacing: -0.2px; }
  .category-desc { color: rgba(226, 232, 240, 0.75); margin-bottom: 14px; font-size: var(--fs-1); }

  .articles-count {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    background: rgba(58, 134, 255, 0.12);
    color: rgba(226, 232, 240, 0.95);
    padding: 6px 12px;
    border-radius: 999px;
    border: 1px solid rgba(58, 134, 255, 0.22);
    font-size: 12px;
    font-weight: 650;
  }

  /* Popular Articles */
  .popular-articles { margin-bottom: 46px; }

  .article-card { padding: 20px; }
  .article-title {
    font-size: 1.05rem;
    margin-bottom: 10px;
    display: flex;
    align-items: center;
    gap: 10px;
    letter-spacing: -0.2px;
  }
  .article-icon {
    color: var(--primary);
    font-size: 16px;
    filter: drop-shadow(0 10px 22px rgba(58,134,255,0.2));
  }
  .article-desc { color: rgba(226, 232, 240, 0.75); font-size: var(--fs-1); margin-bottom: 14px; }

  .article-meta {
    display: flex;
    justify-content: space-between;
    align-items: center;
    color: rgba(148, 163, 184, 0.95);
    font-size: 12px;
    gap: 10px;
  }

  /* Badge */
  .badge {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 8px 12px;
    border-radius: 999px;
    background: rgba(58, 134, 255, 0.12);
    border: 1px solid rgba(58, 134, 255, 0.18);
    color: rgba(226, 232, 240, 0.95);
    font-size: 13px;
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
  }

  /* Breadcrumbs */
  .crumbs {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    align-items: center;
    margin: 10px 0 0;
    justify-content: center;
    color: rgba(148, 163, 184, 0.95);
    font-size: 13px;
  }

  .crumbs a {
    color: rgba(226, 232, 240, 0.9);
    text-decoration: none;
    padding: 6px 10px;
    border-radius: 999px;
    transition: background var(--dur-2) var(--ease-out),
                color var(--dur-2) var(--ease-out),
                transform var(--dur-2) var(--ease-out);
  }
  .crumbs a:hover {
    color: var(--light);
    background: rgba(58, 134, 255, 0.12);
    transform: translateY(-1px);
  }

  /* Article page wrap */
  .article-wrap {
    max-width: 900px;
    margin: 0 auto;
    padding: 26px;
    box-shadow: var(--shadow);
  }

  .article-wrap h2, .article-wrap h3, .article-wrap h4 {
    margin: 18px 0 10px;
    line-height: 1.25;
    letter-spacing: -0.2px;
  }

  .article-wrap p { color: rgba(226, 232, 240, 0.86); margin: 12px 0; }
  .article-wrap ul, .article-wrap ol { margin: 10px 0 10px 22px; }
  .article-wrap li { margin: 8px 0; color: rgba(226, 232, 240, 0.82); }

  .article-wrap a {
    color: var(--primary);
    text-decoration: none;
    border-bottom: 1px solid rgba(58,134,255,0.35);
    transition: border-color var(--dur-2) var(--ease-out), color var(--dur-2) var(--ease-out);
  }
  .article-wrap a:hover {
    color: rgba(167, 201, 255, 1);
    border-bottom-color: rgba(58,134,255,0.7);
  }

  /* Not found */
  .notfound {
    text-align: center;
    padding: 44px 0;
    color: rgba(148, 163, 184, 0.95);
  }

  /* Footer */
  .footer-content {
    display: flex;
    flex-wrap: wrap;
    gap: 40px;
    justify-content: space-between;
  }

  .footer-col { flex: 1; min-width: 200px; }
  .footer-title { font-size: 18px; margin-bottom: 18px; color: var(--light); letter-spacing: -0.2px; }
  .footer-links { list-style: none; padding-left: 0; }
  .footer-links li { margin-bottom: 10px; }

  .footer-links a {
    color: rgba(148, 163, 184, 0.95);
    text-decoration: none;
    padding: 6px 0;
    display: inline-flex;
    transition: color var(--dur-2) var(--ease-out), transform var(--dur-2) var(--ease-out);
  }
  .footer-links a:hover {
    color: rgba(226, 232, 240, 0.95);
    transform: translateX(2px);
  }

  .copyright {
    text-align: center;
    margin-top: 38px;
    padding-top: 18px;
    border-top: 1px solid rgba(51, 65, 85, 0.9);
    color: rgba(148, 163, 184, 0.95);
    font-size: 14px;
  }

  /* Mobile tweaks */
  @media (max-width: 768px) {
    .hero h1 { font-size: clamp(2rem, 6vw, 2.4rem); }
    .categories-grid, .articles-grid { grid-template-columns: 1fr; }
    .article-wrap { padding: 18px; }
  }
}

@layer utilities {
  /* Utility helpers if you ever need them (safe, optional) */
  .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;
  }
}