/* =========================================================
   FONTS — Geist
   ========================================================= */
@import url('https://fonts.googleapis.com/css2?family=Geist:wght@300;400;500;600;700;800;900&display=swap');

/* =========================================================
   DESIGN TOKENS — Light (default)
   ========================================================= */
:root {
  /* Brand (shared) */
  --color-brand:        #6366f1;
  --color-brand-dark:   #4f46e5;
  --color-brand-light:  #818cf8;
  --color-accent:       #22d3ee;
  --color-violet:       #8b5cf6;
  --color-emerald:      #10b981;
  --color-rose:         #f43f5e;
  --color-amber:        #f59e0b;

  /* Light backgrounds */
  --color-bg:           #ffffff;
  --color-surface:      #f9fafb;
  --color-surface-2:    #f3f4f6;
  --color-surface-3:    #e5e7eb;

  /* Light borders */
  --color-border:       rgba(0,0,0,0.07);
  --color-border-light: rgba(0,0,0,0.04);
  --color-border-bright:rgba(0,0,0,0.12);

  /* Light text */
  --color-text:         #0f172a;
  --color-text-2:       #1e293b;
  --color-muted:        #64748b;
  --color-subtle:       #94a3b8;

  /* Semantic */
  --color-positive:     #059669;
  --color-negative:     #e11d48;
  --color-rating:       #f59e0b;
  --color-badge:        #7c3aed;

  /* Light shadows */
  --shadow-sm:    0 1px 3px rgba(15,23,42,.06), 0 1px 2px rgba(15,23,42,.04);
  --shadow-md:    0 4px 16px rgba(15,23,42,.08), 0 1px 4px rgba(15,23,42,.04);
  --shadow-lg:    0 8px 32px rgba(15,23,42,.10), 0 2px 8px rgba(15,23,42,.04);
  --shadow-brand: 0 4px 20px rgba(99,102,241,.28), 0 0 0 1px rgba(99,102,241,.2);
  --shadow-card:  0 0 0 1px rgba(15,23,42,.06), 0 4px 16px rgba(15,23,42,.06);

  /* Layout */
  --max-width:  880px;
  --radius:     8px;
  --radius-lg:  12px;
  --radius-xl:  16px;
  --radius-2xl: 24px;

  /* Spacing */
  --space-1:  4px;  --space-2:  8px;  --space-3:  12px;
  --space-4:  16px; --space-5:  20px; --space-6:  24px;
  --space-8:  32px; --space-10: 40px; --space-12: 48px;
  --space-16: 64px; --space-20: 80px;

  /* Typography */
  --font-sans:      'Geist', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-size-base: 16px;
  --line-height:    1.75;

  /* Motion */
  --t-fast:   0.12s ease;
  --t-base:   0.2s ease;
  --t-smooth: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --t-spring: 0.4s cubic-bezier(0.34, 1.56, 0.64, 1);

  /* Nav glass (light) */
  --nav-bg:     rgba(255,255,255,0.85);
  --nav-mobile: rgba(255,255,255,0.98);
}

/* =========================================================
   DARK THEME OVERRIDES
   ========================================================= */
[data-theme="dark"] {
  --color-bg:            #09090b;
  --color-surface:       #111113;
  --color-surface-2:     #18181b;
  --color-surface-3:     #27272a;

  --color-border:        rgba(255,255,255,0.07);
  --color-border-light:  rgba(255,255,255,0.04);
  --color-border-bright: rgba(255,255,255,0.13);

  --color-text:          #fafafa;
  --color-text-2:        #e4e4e7;
  --color-muted:         #a1a1aa;
  --color-subtle:        #71717a;

  --color-positive:     #10b981;
  --color-negative:     #f43f5e;

  --shadow-sm:    0 1px 2px rgba(0,0,0,0.4);
  --shadow-md:    0 4px 16px rgba(0,0,0,0.5), 0 1px 4px rgba(0,0,0,0.3);
  --shadow-lg:    0 12px 40px rgba(0,0,0,0.6), 0 4px 12px rgba(0,0,0,0.4);
  --shadow-brand: 0 4px 20px rgba(99,102,241,0.4), 0 0 0 1px rgba(99,102,241,0.25);
  --shadow-card:  0 0 0 1px rgba(255,255,255,0.06), 0 8px 24px rgba(0,0,0,0.35);

  --nav-bg:     rgba(9,9,11,0.8);
  --nav-mobile: rgba(9,9,11,0.97);
}

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

html {
  font-size: var(--font-size-base);
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
  color-scheme: light;
  transition: color-scheme 0s;
}
[data-theme="dark"] { color-scheme: dark; }

body {
  font-family: var(--font-sans);
  line-height: var(--line-height);
  color: var(--color-text);
  background: var(--color-bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
  transition: background var(--t-smooth), color var(--t-smooth);
}

/* Dark-mode cursor spotlight */
[data-theme="dark"] body::after {
  content: '';
  position: fixed;
  inset: 0;
  background: radial-gradient(
    700px circle at var(--cursor-x, -9999px) var(--cursor-y, -9999px),
    rgba(99,102,241,0.05),
    transparent 40%
  );
  pointer-events: none;
  z-index: 9998;
}

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

a { color: var(--color-brand); text-decoration: none; transition: color var(--t-fast); }
a:hover { color: var(--color-brand-dark); }
[data-theme="dark"] a { color: var(--color-brand-light); }
[data-theme="dark"] a:hover { color: #fff; }
a:focus-visible { outline: 2px solid var(--color-brand); outline-offset: 3px; border-radius: 3px; }

/* =========================================================
   TYPOGRAPHY
   ========================================================= */
h1, h2, h3, h4 {
  line-height: 1.15;
  font-weight: 700;
  color: var(--color-text);
  letter-spacing: -0.025em;
}
h1 { font-size: clamp(1.875rem, 5vw, 3rem); margin-bottom: var(--space-6); }
h2 { font-size: clamp(1.375rem, 3vw, 1.875rem); margin-top: var(--space-12); margin-bottom: var(--space-4); }
h3 { font-size: 1.25rem; margin-bottom: var(--space-3); }
h4 { font-size: 1rem; margin-bottom: var(--space-2); }
p  { margin-bottom: var(--space-4); color: var(--color-text-2); }
p:last-child { margin-bottom: 0; }
ul, ol { padding-left: var(--space-6); margin-bottom: var(--space-4); }
li { margin-bottom: var(--space-2); color: var(--color-text-2); }
strong { font-weight: 600; color: var(--color-text); }

/* =========================================================
   SCROLL REVEAL
   ========================================================= */
.reveal {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.55s cubic-bezier(0.4, 0, 0.2, 1),
              transform 0.55s cubic-bezier(0.4, 0, 0.2, 1);
}
.reveal.is-visible { opacity: 1; transform: none; }
.reveal--delay-1 { transition-delay: 0.08s; }
.reveal--delay-2 { transition-delay: 0.16s; }
.reveal--delay-3 { transition-delay: 0.24s; }
@media (prefers-reduced-motion: reduce) {
  .reveal { opacity: 1; transform: none; transition: none; }
}

/* =========================================================
   LAYOUT
   ========================================================= */
.container { max-width: var(--max-width); margin-inline: auto; padding-inline: var(--space-4); }
@media (min-width: 768px) { .container { padding-inline: var(--space-8); } }
main { padding-block: var(--space-8); }

/* =========================================================
   SITE HEADER
   ========================================================= */
.site-header {
  background: var(--nav-bg);
  backdrop-filter: blur(20px) saturate(160%);
  -webkit-backdrop-filter: blur(20px) saturate(160%);
  border-bottom: 1px solid var(--color-border);
  position: sticky;
  top: 0;
  z-index: 100;
  transition: border-color var(--t-smooth), box-shadow var(--t-smooth);
}
.site-header.is-scrolled {
  border-bottom-color: var(--color-border-bright);
  box-shadow: var(--shadow-md);
}
.site-header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
  padding-block: 13px;
}
.site-header__logo {
  font-weight: 700;
  font-size: 1rem;
  color: var(--color-text);
  text-decoration: none;
  white-space: nowrap;
  display: flex;
  align-items: center;
  gap: var(--space-2);
  letter-spacing: -0.03em;
  transition: opacity var(--t-fast);
}
.site-header__logo:hover { opacity: 0.75; color: var(--color-text); }
.site-header__logo-icon {
  width: 27px; height: 27px;
  background: linear-gradient(135deg, var(--color-brand), var(--color-accent));
  border-radius: 7px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-size: 0.7rem;
  font-weight: 800;
  flex-shrink: 0;
}

.site-nav__list { display: flex; gap: 2px; list-style: none; padding: 0; margin: 0; align-items: center; }
.site-nav__link {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--color-muted);
  text-decoration: none;
  padding: 6px var(--space-3);
  border-radius: var(--radius);
  transition: color var(--t-fast), background var(--t-fast);
  white-space: nowrap;
}
.site-nav__link:hover { color: var(--color-text); background: var(--color-surface-2); }
.site-nav__link--active { color: var(--color-brand); background: var(--color-surface-2); font-weight: 600; }
[data-theme="dark"] .site-nav__link:hover { background: rgba(255,255,255,0.06); }
[data-theme="dark"] .site-nav__link--active { color: var(--color-brand-light); background: rgba(255,255,255,0.07); }

/* Theme toggle button (injected by JS) */
.theme-toggle {
  background: var(--color-surface-2);
  border: 1px solid var(--color-border-bright);
  border-radius: var(--radius);
  padding: 6px 9px;
  cursor: pointer;
  color: var(--color-muted);
  font-size: 1rem;
  line-height: 1;
  transition: background var(--t-fast), color var(--t-fast), border-color var(--t-fast);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}
.theme-toggle:hover { background: var(--color-surface-3); color: var(--color-text); }
[data-theme="dark"] .theme-toggle:hover { background: rgba(255,255,255,0.1); }

.nav-toggle {
  display: none;
  background: var(--color-surface-2);
  border: 1px solid var(--color-border-bright);
  border-radius: var(--radius);
  padding: 7px 10px;
  cursor: pointer;
  color: var(--color-muted);
  font-size: 1rem;
  line-height: 1;
  transition: background var(--t-fast), color var(--t-fast);
}
.nav-toggle:hover { background: var(--color-surface-3); color: var(--color-text); }

@media (max-width: 640px) {
  .nav-toggle { display: flex; align-items: center; }
  .site-nav {
    position: absolute;
    top: 100%;
    left: 0; right: 0;
    background: var(--nav-mobile);
    backdrop-filter: blur(24px);
    -webkit-backdrop-filter: blur(24px);
    border-bottom: 1px solid var(--color-border);
    padding: var(--space-4);
    box-shadow: var(--shadow-lg);
    visibility: hidden;
    opacity: 0;
    transform: translateY(-10px) scale(0.99);
    pointer-events: none;
    transition: opacity 0.22s ease,
                transform 0.28s cubic-bezier(0.34, 1.56, 0.64, 1),
                visibility 0s linear 0.28s;
  }
  .site-nav.is-open {
    visibility: visible;
    opacity: 1;
    transform: none;
    pointer-events: auto;
    transition: opacity 0.22s ease,
                transform 0.28s cubic-bezier(0.34, 1.56, 0.64, 1),
                visibility 0s linear 0s;
  }
  .site-nav__list { flex-direction: column; align-items: stretch; gap: 2px; }
  .site-nav__link { display: block; padding: var(--space-3) var(--space-4); font-size: 0.9375rem; }
}

/* =========================================================
   BREADCRUMB
   ========================================================= */
.breadcrumb { font-size: 0.8125rem; margin-bottom: var(--space-6); }
.breadcrumb__list { display: flex; flex-wrap: wrap; gap: 4px; list-style: none; padding: 0; margin: 0; align-items: center; }
.breadcrumb__item + .breadcrumb__item::before { content: '/'; margin-right: 4px; color: var(--color-subtle); opacity: 0.5; }
.breadcrumb__link { color: var(--color-subtle); text-decoration: none; transition: color var(--t-fast); }
.breadcrumb__link:hover { color: var(--color-muted); }
.breadcrumb__current { color: var(--color-muted); }

/* =========================================================
   BUTTONS
   ========================================================= */
.btn-primary {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  background: var(--color-brand);
  color: #fff;
  font-weight: 600;
  font-size: 0.9375rem;
  padding: 10px var(--space-6);
  border-radius: var(--radius);
  text-decoration: none;
  transition: background var(--t-base),
              transform 0.25s cubic-bezier(0.34,1.56,0.64,1),
              box-shadow var(--t-base);
  white-space: nowrap;
  border: none;
  cursor: pointer;
  box-shadow: var(--shadow-brand);
  position: relative;
  overflow: hidden;
  will-change: transform;
}
.btn-primary::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, rgba(255,255,255,0.15), transparent 60%);
  opacity: 0;
  transition: opacity var(--t-base);
}
.btn-primary:hover {
  background: var(--color-brand-dark);
  color: #fff;
  transform: translateY(-2px) scale(1.01);
  box-shadow: 0 8px 28px rgba(99,102,241,0.4), 0 0 0 1px rgba(99,102,241,0.3);
}
.btn-primary:hover::before { opacity: 1; }
.btn-primary:active { transform: scale(0.98); box-shadow: var(--shadow-brand); }
.btn-primary:focus-visible { outline: 2px solid var(--color-brand-light); outline-offset: 3px; }

.btn-secondary {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  background: transparent;
  color: var(--color-brand);
  font-weight: 600;
  font-size: 0.9375rem;
  padding: 10px var(--space-6);
  border-radius: var(--radius);
  text-decoration: none;
  transition: background var(--t-base), color var(--t-base), transform var(--t-base);
  border: 1.5px solid var(--color-brand);
  cursor: pointer;
}
.btn-secondary:hover {
  background: var(--color-brand);
  color: #fff;
  transform: translateY(-1px);
}
[data-theme="dark"] .btn-secondary { color: var(--color-brand-light); border-color: rgba(129,140,248,0.4); }
[data-theme="dark"] .btn-secondary:hover { background: rgba(99,102,241,0.15); color: var(--color-brand-light); border-color: var(--color-brand-light); }

/* =========================================================
   FOOTER
   ========================================================= */
.site-footer {
  border-top: 1px solid var(--color-border);
  padding-block: var(--space-12);
  margin-top: var(--space-16);
  font-size: 0.875rem;
  color: var(--color-muted);
  background: var(--color-surface);
  transition: background var(--t-smooth), border-color var(--t-smooth);
}
.footer__inner { display: grid; grid-template-columns: 1.4fr 1fr 1fr; gap: var(--space-8); margin-bottom: var(--space-8); }
@media (max-width: 768px) { .footer__inner { grid-template-columns: 1fr 1fr; } }
@media (max-width: 480px) { .footer__inner { grid-template-columns: 1fr; } }

.footer__brand p { color: var(--color-subtle); font-size: 0.875rem; margin-top: var(--space-3); line-height: 1.6; }
.footer__brand-name { font-weight: 700; font-size: 1rem; color: var(--color-text); letter-spacing: -0.025em; }
.footer__col-title { font-weight: 600; font-size: 0.8125rem; text-transform: uppercase; letter-spacing: 0.07em; color: var(--color-subtle); margin-bottom: var(--space-4); }
.footer__col-links { list-style: none; padding: 0; margin: 0; display: flex; flex-direction: column; gap: var(--space-3); }
.footer__col-links a { color: var(--color-subtle); text-decoration: none; font-size: 0.875rem; transition: color var(--t-fast); }
.footer__col-links a:hover { color: var(--color-brand); }
[data-theme="dark"] .footer__col-links a:hover { color: var(--color-text-2); }

.footer__disclosure {
  background: var(--color-surface-2);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: var(--space-4) var(--space-6);
  margin-bottom: var(--space-6);
  line-height: 1.6;
  font-size: 0.8125rem;
  color: var(--color-subtle);
}
.footer__bottom {
  display: flex; justify-content: space-between; align-items: center;
  flex-wrap: wrap; gap: var(--space-4);
  padding-top: var(--space-6); border-top: 1px solid var(--color-border);
}
.footer__copy { color: var(--color-subtle); font-size: 0.8125rem; }

/* =========================================================
   ERROR PAGE
   ========================================================= */
.error-page { text-align: center; padding-block: var(--space-16); }
.error-page h1 { margin-bottom: var(--space-4); }
.error-page p  { color: var(--color-muted); margin-bottom: var(--space-4); }
.error-page__links {
  list-style: none; padding: 0; margin-bottom: var(--space-8);
  display: flex; flex-wrap: wrap; justify-content: center; gap: var(--space-4);
}

/* =========================================================
   READING PROGRESS BAR
   ========================================================= */
.progress-bar {
  position: fixed;
  top: 0; left: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--color-brand) 0%, var(--color-accent) 50%, var(--color-violet) 100%);
  width: 0%;
  z-index: 500;
  will-change: width;
  pointer-events: none;
  transform-origin: left;
}
[data-theme="dark"] .progress-bar {
  box-shadow: 0 0 10px rgba(99,102,241,0.8), 0 0 24px rgba(34,211,238,0.25);
}

/* =========================================================
   PAGE TRANSITION — MAIN ELEMENT ENTER
   ========================================================= */
main {
  animation: mainEnter 0.4s cubic-bezier(0.4, 0, 0.2, 1) both;
}
@keyframes mainEnter {
  from { opacity: 0; transform: translateY(14px); }
  to   { opacity: 1; transform: none; }
}
main.is-leaving {
  animation: mainLeave 0.2s ease forwards;
  pointer-events: none;
}
@keyframes mainLeave {
  to { opacity: 0; transform: translateY(-8px); }
}
@media (prefers-reduced-motion: reduce) {
  main { animation: none; }
  main.is-leaving { animation: none; }
}

/* =========================================================
   NAV OVERLAY
   ========================================================= */
.nav-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.45);
  backdrop-filter: blur(2px);
  -webkit-backdrop-filter: blur(2px);
  z-index: 98;
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.22s ease, visibility 0s linear 0.22s;
  cursor: pointer;
}
.nav-overlay.is-visible {
  opacity: 1;
  visibility: visible;
  transition: opacity 0.22s ease, visibility 0s linear 0s;
}

/* =========================================================
   NAV TOGGLE — SVG ICON STATE
   ========================================================= */
.nav-toggle__hamburger { display: block; }
.nav-toggle__close    { display: none; }
.nav-toggle[aria-expanded="true"] .nav-toggle__hamburger { display: none; }
.nav-toggle[aria-expanded="true"] .nav-toggle__close    { display: block; }

/* =========================================================
   HERO FLOATING ORBS
   ========================================================= */
.hero__orb {
  position: absolute;
  border-radius: 50%;
  pointer-events: none;
  will-change: transform;
}
.hero__orb--1 {
  width: 440px; height: 440px;
  top: -100px; left: -120px;
  background: radial-gradient(circle, rgba(99,102,241,0.1) 0%, transparent 70%);
  animation: orbDrift1 13s ease-in-out infinite;
}
.hero__orb--2 {
  width: 360px; height: 360px;
  top: -60px; right: -90px;
  background: radial-gradient(circle, rgba(34,211,238,0.07) 0%, transparent 70%);
  animation: orbDrift2 16s ease-in-out infinite;
}
.hero__orb--3 {
  width: 300px; height: 300px;
  bottom: 20px; left: 35%;
  background: radial-gradient(circle, rgba(139,92,246,0.07) 0%, transparent 70%);
  animation: orbDrift3 19s ease-in-out infinite;
}
[data-theme="dark"] .hero__orb--1 {
  background: radial-gradient(circle, rgba(99,102,241,0.18) 0%, transparent 70%);
}
[data-theme="dark"] .hero__orb--2 {
  background: radial-gradient(circle, rgba(34,211,238,0.11) 0%, transparent 70%);
}
[data-theme="dark"] .hero__orb--3 {
  background: radial-gradient(circle, rgba(139,92,246,0.11) 0%, transparent 70%);
}
@keyframes orbDrift1 {
  0%, 100% { transform: translate(0, 0); }
  33%       { transform: translate(28px, 18px); }
  66%       { transform: translate(-18px, 28px); }
}
@keyframes orbDrift2 {
  0%, 100% { transform: translate(0, 0); }
  40%       { transform: translate(-22px, 14px); }
  70%       { transform: translate(18px, -18px); }
}
@keyframes orbDrift3 {
  0%, 100% { transform: translate(0, 0) scale(1); }
  50%       { transform: translate(12px, -22px) scale(1.08); }
}
@media (prefers-reduced-motion: reduce) {
  .hero__orb { animation: none; }
}

/* =========================================================
   REVEAL VARIANTS
   ========================================================= */
.reveal--left  { opacity: 0; transform: translateX(-18px); }
.reveal--right { opacity: 0; transform: translateX(18px); }
.reveal--scale { opacity: 0; transform: scale(0.95) translateY(10px); }
.reveal--left.is-visible,
.reveal--right.is-visible,
.reveal--scale.is-visible {
  opacity: 1;
  transform: none;
}
.reveal--left,
.reveal--right,
.reveal--scale {
  transition: opacity 0.5s cubic-bezier(0.4, 0, 0.2, 1),
              transform 0.5s cubic-bezier(0.4, 0, 0.2, 1);
}

/* Stagger delays for grid children */
.reveal--stagger-1 { transition-delay: 0.05s; }
.reveal--stagger-2 { transition-delay: 0.10s; }
.reveal--stagger-3 { transition-delay: 0.15s; }
.reveal--stagger-4 { transition-delay: 0.20s; }
.reveal--stagger-5 { transition-delay: 0.25s; }
.reveal--stagger-6 { transition-delay: 0.30s; }

/* =========================================================
   SCROLLBAR STYLING
   ========================================================= */
::-webkit-scrollbar { width: 6px; height: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb {
  background: var(--color-surface-3);
  border-radius: 3px;
}
::-webkit-scrollbar-thumb:hover { background: var(--color-muted); opacity: 0.7; }
[data-theme="dark"] ::-webkit-scrollbar-thumb { background: rgba(255,255,255,0.12); }
[data-theme="dark"] ::-webkit-scrollbar-thumb:hover { background: rgba(255,255,255,0.22); }

/* =========================================================
   3D CARD TILT PERSPECTIVE (desktop)
   ========================================================= */
@media (hover: hover) {
  .tool-card, .category-card {
    transform-style: preserve-3d;
    will-change: transform;
    perspective: 800px;
  }
}