/* ============================================================
   Vücut Yağ Oranı Hesaplayıcı — Premium Design System v2
   Senior-Level Frontend Architecture
   ============================================================ */

/* ---- CSS CUSTOM PROPERTIES ---- */
:root {
  --bg:        #f0f4f8;
  --bg-alt:    #e2e8f0;
  --bg-subtle: #f8fafc;
  --card:      #ffffff;
  --card-alt:  #f8fafc;
  --card-glass:rgba(255,255,255,.72);
  --text:      #0f172a;
  --text-inv:  #f1f5f9;
  --muted:     #64748b;
  --muted-2:   #94a3b8;
  --border:    #e2e8f0;
  --border-2:  #cbd5e1;
  --accent:    #0891b2;
  --accent-h:  #06b6d4;
  --accent-l:  rgba(8,145,178,.08);
  --accent-m:  rgba(8,145,178,.15);
  --accent2:   #f59e0b;
  --accent2-h: #fbbf24;
  --success:   #10b981;
  --success-l: rgba(16,185,129,.1);
  --warn:      #f59e0b;
  --warn-l:    rgba(245,158,11,.1);
  --danger:    #ef4444;
  --danger-l:  rgba(239,68,68,.1);
  --gradient-hero: linear-gradient(135deg, #0891b2 0%, #0e7490 30%, #164e63 100%);
  --gradient-card: linear-gradient(145deg, var(--card) 0%, var(--bg-subtle) 100%);
  --gradient-accent: linear-gradient(135deg, #0891b2 0%, #06b6d4 50%, #22d3ee 100%);
  --gradient-warm: linear-gradient(135deg, #f59e0b 0%, #f97316 100%);
  --radius:    14px;
  --radius-sm: 10px;
  --radius-xs: 6px;
  --radius-lg: 20px;
  --shadow-xs: 0 1px 2px rgba(0,0,0,.04);
  --shadow:    0 1px 3px rgba(0,0,0,.06), 0 1px 2px rgba(0,0,0,.04);
  --shadow-md: 0 4px 6px -1px rgba(0,0,0,.07), 0 2px 4px -2px rgba(0,0,0,.05);
  --shadow-lg: 0 10px 25px -5px rgba(0,0,0,.08), 0 8px 10px -6px rgba(0,0,0,.04);
  --shadow-xl: 0 20px 50px -12px rgba(0,0,0,.12);
  --shadow-accent: 0 8px 30px -6px rgba(8,145,178,.28);
  --font: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --mono: "SF Mono", SFMono-Regular, ui-monospace, Consolas, "Liberation Mono", Menlo, monospace;
  --max-w: 1200px;
  --header-h: 68px;
  --ease: cubic-bezier(.4,0,.2,1);
  --ease-spring: cubic-bezier(.34,1.56,.64,1);
  --ease-out: cubic-bezier(0,0,.2,1);
}

[data-theme="dark"] {
  --bg:        #0c1222;
  --bg-alt:    #162033;
  --bg-subtle: #131d30;
  --card:      #1a2744;
  --card-alt:  #1e2d4a;
  --card-glass:rgba(26,39,68,.78);
  --text:      #e8edf5;
  --text-inv:  #0f172a;
  --muted:     #8b9ec2;
  --muted-2:   #6b82ad;
  --border:    #253552;
  --border-2:  #2d4168;
  --accent:    #22d3ee;
  --accent-h:  #67e8f9;
  --accent-l:  rgba(34,211,238,.06);
  --accent-m:  rgba(34,211,238,.12);
  --accent2:   #fbbf24;
  --accent2-h: #fde68a;
  --success-l: rgba(16,185,129,.08);
  --warn-l:    rgba(245,158,11,.08);
  --danger-l:  rgba(239,68,68,.08);
  --gradient-hero: linear-gradient(135deg, #0c4a6e 0%, #164e63 30%, #1a2744 100%);
  --gradient-card: linear-gradient(145deg, var(--card) 0%, var(--bg-subtle) 100%);
  --shadow-xs: 0 1px 2px rgba(0,0,0,.15);
  --shadow:    0 1px 3px rgba(0,0,0,.2), 0 1px 2px rgba(0,0,0,.12);
  --shadow-md: 0 4px 6px -1px rgba(0,0,0,.25), 0 2px 4px -2px rgba(0,0,0,.15);
  --shadow-lg: 0 10px 25px -5px rgba(0,0,0,.3), 0 8px 10px -6px rgba(0,0,0,.2);
  --shadow-xl: 0 20px 50px -12px rgba(0,0,0,.4);
  --shadow-accent: 0 8px 30px -6px rgba(34,211,238,.2);
}

/* ---- RESET ---- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; text-size-adjust: 100%; }
body {
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}
a { color: var(--accent); text-decoration: none; transition: color .2s var(--ease); }
a:hover { color: var(--accent-h); }
img { max-width: 100%; display: block; }
ul, ol { padding-left: 1.5em; }
::selection { background: var(--accent-m); color: var(--accent); }

/* ---- ANIMATIONS ---- */
@keyframes fadeInUp {
  from { opacity: 0; transform: translateY(24px); }
  to   { opacity: 1; transform: translateY(0); }
}
@keyframes fadeIn {
  from { opacity: 0; }
  to   { opacity: 1; }
}
@keyframes slideInLeft {
  from { opacity: 0; transform: translateX(-20px); }
  to   { opacity: 1; transform: translateX(0); }
}
@keyframes slideInRight {
  from { opacity: 0; transform: translateX(20px); }
  to   { opacity: 1; transform: translateX(0); }
}
@keyframes scaleIn {
  from { opacity: 0; transform: scale(.92); }
  to   { opacity: 1; transform: scale(1); }
}
@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: .6; }
}
@keyframes float {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-8px); }
}
@keyframes shimmer {
  0% { background-position: -200% 0; }
  100% { background-position: 200% 0; }
}
@keyframes countUp {
  from { opacity: 0; transform: translateY(12px); }
  to   { opacity: 1; transform: translateY(0); }
}
@keyframes gradientShift {
  0% { background-position: 0% 50%; }
  50% { background-position: 100% 50%; }
  100% { background-position: 0% 50%; }
}
.animate-fade-up { animation: fadeInUp .6s var(--ease) both; }
.animate-fade-in { animation: fadeIn .5s var(--ease) both; }
.animate-scale   { animation: scaleIn .5s var(--ease-spring) both; }
.delay-1 { animation-delay: .1s; }
.delay-2 { animation-delay: .2s; }
.delay-3 { animation-delay: .3s; }
.delay-4 { animation-delay: .4s; }
.delay-5 { animation-delay: .5s; }

/* ---- TYPOGRAPHY ---- */
h1, h2, h3, h4, h5, h6 {
  line-height: 1.25;
  font-weight: 800;
  color: var(--text);
  letter-spacing: -.02em;
}
h1 { font-size: clamp(2rem, 5vw, 3rem); margin-bottom: .75rem; }
h2 { font-size: clamp(1.5rem, 3.5vw, 2rem); margin-bottom: .6rem; }
h3 { font-size: clamp(1.15rem, 2.5vw, 1.45rem); margin-bottom: .5rem; }
p  { margin-bottom: 1rem; }

/* ---- LAYOUT ---- */
.container { width: 100%; max-width: var(--max-w); margin: 0 auto; padding: 0 1.5rem; }
.section   { padding: 4rem 0; }
.section-sm { padding: 2.5rem 0; }
.grid-2    { display: grid; grid-template-columns: 1fr 1fr; gap: 1.5rem; }
.grid-3    { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1.5rem; }
.grid-4    { display: grid; grid-template-columns: repeat(4, 1fr); gap: 1.25rem; }
@media (max-width: 900px) {
  .grid-2 { grid-template-columns: 1fr; }
  .grid-3 { grid-template-columns: 1fr 1fr; }
  .grid-4 { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 600px) {
  .grid-3, .grid-4 { grid-template-columns: 1fr; }
  .section { padding: 3rem 0; }
}

/* ---- HEADER ---- */
.header {
  background: var(--card-glass);
  -webkit-backdrop-filter: blur(16px) saturate(1.8);
  backdrop-filter: blur(16px) saturate(1.8);
  border-bottom: 1px solid var(--border);
  position: sticky; top: 0; z-index: 100;
  height: var(--header-h);
  transition: box-shadow .3s var(--ease);
}
.header.scrolled { box-shadow: var(--shadow-md); }
.header .container {
  display: flex; align-items: center; justify-content: space-between;
  height: 100%;
}
.header__logo {
  font-weight: 900; font-size: 1.2rem; color: var(--accent);
  display: flex; align-items: center; gap: .6rem;
  letter-spacing: -.01em;
}
.header__logo:hover { text-decoration: none; color: var(--accent-h); }
.header__logo svg { width: 30px; height: 30px; }
.header__nav { display: flex; align-items: center; gap: .15rem; }
.header__nav a {
  padding: .5rem .85rem; border-radius: var(--radius-sm);
  font-size: .88rem; font-weight: 600; color: var(--muted);
  transition: all .2s var(--ease); position: relative;
}
.header__nav a:hover { background: var(--accent-l); color: var(--accent); text-decoration: none; }
.header__nav a.active { background: var(--accent-l); color: var(--accent); }
.header__nav a.active::after {
  content: ""; position: absolute; bottom: 2px; left: 50%;
  transform: translateX(-50%); width: 18px; height: 2.5px;
  background: var(--accent); border-radius: 99px;
}
.header__actions { display: flex; align-items: center; gap: .5rem; }

.hamburger {
  display: none; background: none; border: none; cursor: pointer;
  width: 40px; height: 40px; color: var(--text);
  border-radius: var(--radius-sm); transition: background .2s;
}
.hamburger:hover { background: var(--bg-alt); }
.hamburger svg { width: 22px; height: 22px; }

@media (max-width: 768px) {
  .hamburger { display: flex; align-items: center; justify-content: center; }
  .header__nav {
    display: none; position: absolute; top: var(--header-h); left: 0; right: 0;
    background: var(--card-glass);
    -webkit-backdrop-filter: blur(16px) saturate(1.8);
    backdrop-filter: blur(16px) saturate(1.8);
    border-bottom: 1px solid var(--border);
    flex-direction: column; padding: .5rem .75rem;
    box-shadow: var(--shadow-lg);
  }
  .header__nav.open { display: flex; animation: fadeIn .2s var(--ease); }
  .header__nav a { width: 100%; padding: .85rem 1rem; border-radius: var(--radius-xs); }
  .header__nav a.active::after { display: none; }
}

/* ---- THEME TOGGLE ---- */
.theme-toggle {
  background: var(--accent-l); border: 1px solid var(--border); border-radius: var(--radius-sm);
  width: 40px; height: 40px; cursor: pointer; color: var(--muted);
  display: flex; align-items: center; justify-content: center;
  transition: all .25s var(--ease);
}
.theme-toggle:hover { background: var(--accent-m); color: var(--accent); border-color: var(--accent); transform: rotate(15deg); }
.theme-toggle svg { width: 18px; height: 18px; transition: transform .3s var(--ease-spring); }
[data-theme="dark"] .theme-toggle .icon-sun  { display: block; }
[data-theme="dark"] .theme-toggle .icon-moon { display: none; }
.theme-toggle .icon-sun  { display: none; }
.theme-toggle .icon-moon { display: block; }

/* ---- HERO ---- */
.hero {
  position: relative; overflow: hidden;
  padding: 4.5rem 0 3.5rem;
  background: var(--gradient-hero);
  color: #fff;
}
.hero::before {
  content: ""; position: absolute; inset: 0;
  background:
    radial-gradient(ellipse 600px 400px at 20% 80%, rgba(34,211,238,.15) 0%, transparent 70%),
    radial-gradient(ellipse 500px 350px at 80% 20%, rgba(6,182,212,.12) 0%, transparent 70%),
    radial-gradient(ellipse 300px 300px at 50% 50%, rgba(255,255,255,.03) 0%, transparent 60%);
  pointer-events: none;
}
.hero::after {
  content: ""; position: absolute; bottom: -2px; left: 0; right: 0; height: 60px;
  background: var(--bg);
  clip-path: ellipse(55% 100% at 50% 100%);
}
.hero .container { position: relative; z-index: 1; text-align: center; }
.hero h1 {
  color: #fff; max-width: 800px; margin: 0 auto .5rem;
  font-size: clamp(2.2rem, 5.5vw, 3.25rem);
  animation: fadeInUp .7s var(--ease) both;
}
.hero h1 .hero-badge {
  display: inline-block; font-size: .42em; font-weight: 600;
  background: rgba(255,255,255,.15); border: 1px solid rgba(255,255,255,.2);
  padding: .2em .7em; border-radius: 99px; vertical-align: middle;
  margin-left: .5em; letter-spacing: .02em;
  -webkit-backdrop-filter: blur(8px);
  backdrop-filter: blur(8px);
}
.hero__sub {
  max-width: 600px; margin: 0 auto 2rem;
  color: rgba(255,255,255,.8); font-size: 1.1rem; line-height: 1.7;
  animation: fadeInUp .7s var(--ease) .1s both;
}
.hero__actions {
  display: flex; gap: .75rem; justify-content: center; flex-wrap: wrap;
  animation: fadeInUp .7s var(--ease) .2s both;
}
.hero__actions .btn-hero {
  padding: .8rem 2rem; font-size: 1rem; font-weight: 700;
  border-radius: var(--radius); border: none; cursor: pointer;
  transition: all .25s var(--ease); font-family: var(--font);
}
.hero__actions .btn-hero--primary {
  background: #fff; color: #0e7490;
  box-shadow: 0 4px 20px rgba(0,0,0,.15);
}
.hero__actions .btn-hero--primary:hover {
  transform: translateY(-2px); box-shadow: 0 8px 30px rgba(0,0,0,.2);
  background: #f0fdfa;
}
.hero__actions .btn-hero--ghost {
  background: rgba(255,255,255,.12); color: #fff;
  border: 1px solid rgba(255,255,255,.25);
  -webkit-backdrop-filter: blur(8px);
  backdrop-filter: blur(8px);
}
.hero__actions .btn-hero--ghost:hover {
  background: rgba(255,255,255,.2); transform: translateY(-2px);
}

/* ---- STATS BAR ---- */
.stats-bar {
  display: flex; justify-content: center; gap: 3rem; flex-wrap: wrap;
  padding: 2.5rem 0 0; margin-top: 2.5rem;
  border-top: 1px solid rgba(255,255,255,.12);
  animation: fadeInUp .7s var(--ease) .3s both;
}
.stats-bar__item { text-align: center; }
.stats-bar__num {
  font-size: 2rem; font-weight: 900; color: #fff;
  letter-spacing: -.03em; line-height: 1;
}
.stats-bar__label {
  font-size: .82rem; color: rgba(255,255,255,.6);
  margin-top: .25rem; font-weight: 500;
}
@media (max-width: 600px) {
  .stats-bar { gap: 2rem; }
  .stats-bar__num { font-size: 1.6rem; }
}

/* ---- TRUST STRIP ---- */
.trust-strip {
  background: var(--card); border-bottom: 1px solid var(--border);
  padding: 1.25rem 0; text-align: center;
  font-size: .85rem; color: var(--muted); font-weight: 500;
}
.trust-strip__items {
  display: flex; justify-content: center; gap: 2rem; flex-wrap: wrap;
  align-items: center;
}
.trust-strip__item {
  display: flex; align-items: center; gap: .4rem;
}
.trust-strip__item svg { width: 16px; height: 16px; color: var(--accent); flex-shrink: 0; }

/* ---- FEATURE CARDS ---- */
.features {
  display: grid; grid-template-columns: repeat(3, 1fr); gap: 1.5rem;
}
@media (max-width: 900px) { .features { grid-template-columns: 1fr 1fr; } }
@media (max-width: 600px) { .features { grid-template-columns: 1fr; } }

.feature-card {
  background: var(--gradient-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 2rem;
  transition: all .3s var(--ease);
  position: relative; overflow: hidden;
}
.feature-card::before {
  content: ""; position: absolute; top: 0; left: 0; right: 0; height: 3px;
  background: var(--gradient-accent); opacity: 0;
  transition: opacity .3s var(--ease);
}
.feature-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
  border-color: var(--accent);
}
.feature-card:hover::before { opacity: 1; }
.feature-card__icon {
  width: 52px; height: 52px; border-radius: var(--radius-sm);
  background: var(--accent-l); color: var(--accent);
  display: flex; align-items: center; justify-content: center;
  margin-bottom: 1.25rem; transition: all .3s var(--ease);
}
.feature-card:hover .feature-card__icon {
  background: var(--accent); color: #fff;
  transform: scale(1.08);
  box-shadow: var(--shadow-accent);
}
.feature-card__icon svg { width: 24px; height: 24px; }
.feature-card__title {
  font-size: 1.15rem; font-weight: 700; margin-bottom: .5rem;
  letter-spacing: -.01em;
}
.feature-card__desc { font-size: .9rem; color: var(--muted); line-height: 1.65; margin: 0; }

/* ---- HOW IT WORKS ---- */
.steps {
  display: grid; grid-template-columns: repeat(4, 1fr); gap: 1rem;
  counter-reset: step;
  position: relative;
}
.steps::before {
  content: ""; position: absolute; top: 32px; left: 12%; right: 12%;
  height: 2px; background: var(--border);
}
@media (max-width: 800px) {
  .steps { grid-template-columns: 1fr 1fr; }
  .steps::before { display: none; }
}
@media (max-width: 500px) { .steps { grid-template-columns: 1fr; } }

.step {
  text-align: center; position: relative;
  counter-increment: step;
}
.step__num {
  width: 56px; height: 56px; border-radius: 50%;
  background: var(--card); border: 2.5px solid var(--accent);
  color: var(--accent); font-weight: 900; font-size: 1.2rem;
  display: flex; align-items: center; justify-content: center;
  margin: 0 auto 1rem; position: relative; z-index: 2;
  box-shadow: var(--shadow);
  transition: all .3s var(--ease);
}
.step:hover .step__num {
  background: var(--accent); color: #fff;
  transform: scale(1.12);
  box-shadow: var(--shadow-accent);
}
.step__title { font-size: 1rem; font-weight: 700; margin-bottom: .35rem; }
.step__desc  { font-size: .85rem; color: var(--muted); line-height: 1.6; }

/* ---- DISCLAIMER ---- */
.disclaimer {
  background: var(--warn-l);
  border: 1px solid rgba(245,158,11,.25);
  border-radius: var(--radius);
  padding: 1.1rem 1.35rem;
  margin-bottom: 1.5rem;
  font-size: .88rem; line-height: 1.65;
  color: var(--text);
  position: relative;
  display: flex; gap: .75rem; align-items: flex-start;
}
.disclaimer::before {
  content: "⚠"; font-size: 1.1rem; flex-shrink: 0; margin-top: .05rem;
}
.disclaimer strong { display: block; margin-bottom: .15rem; font-weight: 700; }
[data-theme="dark"] .disclaimer { border-color: rgba(245,158,11,.15); }

/* ---- CARDS ---- */
.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.75rem;
  box-shadow: var(--shadow);
  transition: all .3s var(--ease);
}
.card:hover { box-shadow: var(--shadow-md); }
.card--link {
  display: block; color: inherit; position: relative; overflow: hidden;
}
.card--link::after {
  content: "→"; position: absolute; bottom: 1.25rem; right: 1.25rem;
  font-size: 1.1rem; color: var(--accent); opacity: 0;
  transform: translateX(-8px);
  transition: all .3s var(--ease);
}
.card--link:hover {
  text-decoration: none; transform: translateY(-3px);
  box-shadow: var(--shadow-lg); border-color: var(--accent);
}
.card--link:hover::after { opacity: 1; transform: translateX(0); }
.card__tag {
  display: inline-block; font-size: .7rem; font-weight: 700;
  padding: .2rem .65rem; border-radius: 99px;
  background: var(--accent-l); color: var(--accent);
  margin-bottom: .85rem; text-transform: uppercase; letter-spacing: .06em;
}
.card__tag--warn { background: var(--warn-l); color: var(--accent2); }
.card__tag--success { background: var(--success-l); color: var(--success); }
.card__title { font-size: 1.1rem; font-weight: 700; margin-bottom: .45rem; letter-spacing: -.01em; }
.card__desc  { font-size: .88rem; color: var(--muted); line-height: 1.65; margin: 0; }

/* ---- SECTION HEADER ---- */
.section-header { text-align: center; max-width: 650px; margin: 0 auto 2.5rem; }
.section-header__label {
  display: inline-block; font-size: .78rem; font-weight: 700;
  color: var(--accent); text-transform: uppercase; letter-spacing: .08em;
  margin-bottom: .6rem;
  background: var(--accent-l); padding: .3rem .9rem;
  border-radius: 99px;
}
.section-header h2 { margin-bottom: .5rem; }
.section-header p { color: var(--muted); font-size: 1.05rem; margin: 0; }

/* ---- SEGMENTED CONTROL ---- */
.seg-control {
  display: inline-flex; background: var(--bg-alt); border-radius: var(--radius-sm);
  padding: 4px; gap: 4px; border: 1px solid var(--border);
}
.seg-control__btn {
  padding: .55rem 1.5rem; border: none; border-radius: var(--radius-xs);
  font-size: .9rem; font-weight: 700; cursor: pointer;
  background: transparent; color: var(--muted);
  transition: all .25s var(--ease); font-family: var(--font);
}
.seg-control__btn.active {
  background: var(--accent); color: #fff;
  box-shadow: 0 2px 8px rgba(8,145,178,.25);
}
.seg-control__btn:hover:not(.active) { background: var(--card); color: var(--text); }

/* ---- FORM ---- */
.form-group { margin-bottom: 1.35rem; }
.form-label {
  display: block; margin-bottom: .45rem; font-size: .88rem;
  font-weight: 700; color: var(--text);
}
.form-label .optional { font-weight: 400; color: var(--muted); font-size: .82rem; }
.form-input {
  width: 100%; padding: .75rem 1rem; font-size: 1rem;
  border: 2px solid var(--border); border-radius: var(--radius-sm);
  background: var(--bg-subtle); color: var(--text);
  transition: all .25s var(--ease);
  font-family: var(--font);
}
.form-input:focus {
  outline: none; border-color: var(--accent);
  box-shadow: 0 0 0 4px var(--accent-m);
  background: var(--card);
}
.form-input:hover:not(:focus) { border-color: var(--border-2); }
.form-input.error { border-color: var(--danger); box-shadow: 0 0 0 4px var(--danger-l); }
.form-error { font-size: .82rem; color: var(--danger); margin-top: .35rem; display: none; font-weight: 500; }
.form-error.show { display: block; }
.form-hint { font-size: .82rem; color: var(--muted); margin-top: .35rem; }
.form-row { display: grid; grid-template-columns: 1fr 1fr; gap: 1.25rem; }
@media (max-width: 500px) { .form-row { grid-template-columns: 1fr; } }

/* ---- TOGGLE SWITCH ---- */
.toggle-wrap { display: flex; align-items: center; gap: .75rem; cursor: pointer; }
.toggle {
  position: relative; width: 48px; height: 26px;
  background: var(--border-2); border-radius: 99px;
  transition: background .25s var(--ease); flex-shrink: 0;
}
.toggle::after {
  content: ""; position: absolute; top: 3px; left: 3px;
  width: 20px; height: 20px; border-radius: 50%;
  background: #fff; transition: transform .25s var(--ease-spring);
  box-shadow: 0 1px 4px rgba(0,0,0,.18);
}
.toggle.active { background: var(--accent); }
.toggle.active::after { transform: translateX(22px); }
.toggle-label { font-size: .88rem; color: var(--text); user-select: none; font-weight: 500; }

/* ---- BUTTONS ---- */
.btn {
  display: inline-flex; align-items: center; gap: .5rem;
  padding: .75rem 1.5rem; font-size: .93rem; font-weight: 700;
  border: none; border-radius: var(--radius-sm); cursor: pointer;
  transition: all .25s var(--ease);
  font-family: var(--font); text-align: center; justify-content: center;
  position: relative; overflow: hidden;
}
.btn:active { transform: scale(.96); }
.btn-primary {
  background: var(--gradient-accent); background-size: 200% auto;
  color: #fff;
}
.btn-primary:hover {
  background-position: right center;
  box-shadow: var(--shadow-accent);
  text-decoration: none; color: #fff;
  transform: translateY(-1px);
}
.btn-secondary {
  background: var(--card); color: var(--text);
  border: 1.5px solid var(--border);
}
.btn-secondary:hover {
  background: var(--bg-subtle); text-decoration: none;
  border-color: var(--accent); color: var(--accent);
}
.btn-ghost { background: transparent; color: var(--accent); }
.btn-ghost:hover { background: var(--accent-l); text-decoration: none; }
.btn-sm { padding: .5rem 1.1rem; font-size: .84rem; }
.btn-lg { padding: .9rem 2rem; font-size: 1.05rem; }
.btn-block { width: 100%; }
.btn-group { display: flex; flex-wrap: wrap; gap: .5rem; margin-top: 1rem; }

/* ---- RESULT ---- */
.result-panel {
  background: var(--gradient-hero);
  border-radius: var(--radius-lg); padding: 2.5rem 2rem; color: #fff;
  text-align: center; margin: 2rem 0;
  box-shadow: var(--shadow-accent);
  display: none; position: relative; overflow: hidden;
}
.result-panel::before {
  content: ""; position: absolute; inset: 0;
  background:
    radial-gradient(circle 200px at 20% 30%, rgba(255,255,255,.08) 0%, transparent 70%),
    radial-gradient(circle 150px at 80% 70%, rgba(34,211,238,.1) 0%, transparent 60%);
  pointer-events: none;
}
.result-panel.show { display: block; animation: scaleIn .4s var(--ease-spring); }
.result-panel__label {
  font-size: .9rem; opacity: .8; margin-bottom: .35rem;
  font-weight: 500; letter-spacing: .02em;
}
.result-panel__value {
  font-size: clamp(3rem, 8vw, 4.5rem); font-weight: 900;
  letter-spacing: -.04em; line-height: 1;
  position: relative; z-index: 1;
}
.result-panel__unit { font-size: 1.5rem; font-weight: 600; opacity: .7; }
.result-panel__note {
  font-size: .85rem; opacity: .65; margin-top: 1rem;
  max-width: 400px; margin-left: auto; margin-right: auto;
}

.result-details { display: none; margin-top: 1.25rem; }
.result-details.show { display: grid; grid-template-columns: 1fr 1fr 1fr; gap: 1rem; }
@media (max-width: 600px) { .result-details.show { grid-template-columns: 1fr; } }

.result-stat {
  background: var(--gradient-card);
  border: 1px solid var(--border);
  border-radius: var(--radius); padding: 1.25rem; text-align: center;
}
.result-stat__label { font-size: .8rem; color: var(--muted); margin-bottom: .3rem; font-weight: 600; }
.result-stat__value { font-size: 1.65rem; font-weight: 800; color: var(--accent); letter-spacing: -.02em; }

/* ---- INTERPRETATION ---- */
.interp-card {
  background: var(--gradient-card);
  border: 1px solid var(--border);
  border-radius: var(--radius); padding: 1.75rem;
  margin-top: 1.5rem; display: none;
}
.interp-card.show { display: block; animation: fadeInUp .4s var(--ease); }
.interp-badge {
  display: inline-flex; align-items: center; gap: .35rem;
  padding: .35rem 1rem; border-radius: 99px;
  font-weight: 700; font-size: .88rem; margin-bottom: .85rem;
}
.interp-badge--low    { background: var(--success-l); color: #059669; }
.interp-badge--mid    { background: rgba(59,130,246,.1); color: #2563eb; }
.interp-badge--high   { background: var(--danger-l); color: #dc2626; }
[data-theme="dark"] .interp-badge--low  { background: rgba(16,185,129,.12); color: #34d399; }
[data-theme="dark"] .interp-badge--mid  { background: rgba(59,130,246,.12); color: #93c5fd; }
[data-theme="dark"] .interp-badge--high { background: rgba(239,68,68,.12); color: #fca5a5; }

.interp-bar {
  width: 100%; height: 10px; border-radius: 99px;
  background: linear-gradient(to right, #10b981 0%, #10b981 33%, #3b82f6 33%, #3b82f6 66%, #ef4444 66%, #ef4444 100%);
  position: relative; margin: 1.25rem 0 .6rem;
  box-shadow: inset 0 1px 3px rgba(0,0,0,.1);
}
.interp-bar__marker {
  position: absolute; top: -6px; width: 22px; height: 22px;
  border-radius: 50%; background: var(--text); border: 3px solid var(--card);
  transform: translateX(-50%); transition: left .5s var(--ease-spring);
  box-shadow: 0 2px 8px rgba(0,0,0,.25);
}
.interp-labels {
  display: flex; justify-content: space-between;
  font-size: .78rem; color: var(--muted); font-weight: 600;
}

/* ---- MEASURE TIPS ---- */
.tips-list { list-style: none; padding: 0; }
.tips-list li {
  padding: .75rem 0 .75rem 2.25rem; position: relative;
  border-bottom: 1px solid var(--border); font-size: .9rem;
}
.tips-list li:last-child { border-bottom: none; }
.tips-list li::before {
  content: ""; position: absolute; left: 0; top: .85rem;
  width: 20px; height: 20px; border-radius: 50%;
  background: var(--accent-l);
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%230891b2' stroke-width='3' stroke-linecap='round'%3E%3Cpath d='M20 6L9 17l-5-5'/%3E%3C/svg%3E");
  background-size: 12px; background-position: center; background-repeat: no-repeat;
}

/* ---- BREADCRUMB ---- */
.breadcrumb {
  display: flex; flex-wrap: wrap; gap: .35rem; align-items: center;
  font-size: .84rem; color: var(--muted); padding: 1.25rem 0 0;
}
.breadcrumb a { color: var(--muted); font-weight: 500; }
.breadcrumb a:hover { color: var(--accent); }
.breadcrumb span { color: var(--text); font-weight: 600; }
.breadcrumb .sep { margin: 0 .1rem; opacity: .4; }

/* ---- FAQ ACCORDION ---- */
.faq-item {
  border: 1px solid var(--border); border-radius: var(--radius);
  margin-bottom: .75rem; overflow: hidden;
  background: var(--card);
  transition: border-color .3s var(--ease), box-shadow .3s var(--ease);
}
.faq-item.open { border-color: var(--accent); box-shadow: 0 0 0 3px var(--accent-l); }
.faq-q {
  padding: 1.1rem 1.35rem; cursor: pointer; font-weight: 700;
  display: flex; justify-content: space-between; align-items: center;
  font-size: .95rem; transition: all .2s var(--ease);
  user-select: none; gap: 1rem;
}
.faq-q:hover { color: var(--accent); }
.faq-q::after {
  content: "+"; font-size: 1.4rem; font-weight: 400; color: var(--muted);
  transition: transform .3s var(--ease-spring); flex-shrink: 0;
  width: 28px; height: 28px; border-radius: 50%;
  background: var(--bg-alt);
  display: flex; align-items: center; justify-content: center;
  font-size: 1.1rem;
}
.faq-item.open .faq-q::after { content: "−"; background: var(--accent-l); color: var(--accent); transform: rotate(180deg); }
.faq-a {
  max-height: 0; overflow: hidden;
  transition: max-height .35s var(--ease), padding .35s var(--ease);
  padding: 0 1.35rem; font-size: .9rem; color: var(--muted); line-height: 1.75;
}
.faq-item.open .faq-a { max-height: 600px; padding: 0 1.35rem 1.35rem; }

/* ---- SEARCH ---- */
.search-box { position: relative; max-width: 600px; margin: 0 auto 1.5rem; }
.search-box input {
  width: 100%; padding: .9rem 1.1rem .9rem 3rem; font-size: 1rem;
  border: 2px solid var(--border); border-radius: var(--radius);
  background: var(--card); color: var(--text); font-family: var(--font);
  transition: all .25s var(--ease);
}
.search-box input:focus {
  outline: none; border-color: var(--accent);
  box-shadow: 0 0 0 4px var(--accent-m);
}
.search-box svg {
  position: absolute; left: 1rem; top: 50%; transform: translateY(-50%);
  width: 18px; height: 18px; color: var(--muted);
}
.filter-chips {
  display: flex; flex-wrap: wrap; gap: .5rem; justify-content: center; margin-bottom: 1.5rem;
}
.chip {
  padding: .4rem 1rem; border-radius: 99px; font-size: .82rem; font-weight: 700;
  background: var(--card); color: var(--muted); border: 1.5px solid var(--border);
  cursor: pointer; transition: all .2s var(--ease);
}
.chip.active, .chip:hover {
  background: var(--accent); color: #fff; border-color: var(--accent);
  box-shadow: 0 2px 8px rgba(8,145,178,.2);
}
.search-results { max-width: 700px; margin: 0 auto; }
.search-result {
  padding: 1.25rem; border-bottom: 1px solid var(--border);
  transition: background .2s var(--ease);
}
.search-result:hover { background: var(--accent-l); }
.search-result__title { font-weight: 700; margin-bottom: .2rem; }
.search-result__url   { font-size: .8rem; color: var(--accent); margin-bottom: .2rem; }
.search-result__desc  { font-size: .88rem; color: var(--muted); }

/* ---- INTERNAL LINKS ---- */
.link-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(280px, 1fr)); gap: 1.25rem; margin-top: 1.5rem; }

/* ---- ARTICLE ---- */
.article { max-width: 760px; margin: 0 auto; padding: 2rem 0 3rem; }
.article h1 { margin-bottom: 1.25rem; }
.article h2 { margin-top: 2.5rem; }
.article h3 { margin-top: 1.75rem; }
.article p  { color: var(--text); }
.article ul, .article ol { margin-bottom: 1rem; }
.article li { margin-bottom: .5rem; }
.article blockquote {
  border-left: 4px solid var(--accent); padding: 1rem 1.5rem;
  background: var(--accent-l); border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  margin: 1.5rem 0; color: var(--text); font-style: normal;
}
.article blockquote p { margin: 0; font-weight: 500; }
.article table { width: 100%; border-collapse: collapse; margin: 1.5rem 0; font-size: .9rem; }
.article th, .article td { padding: .7rem 1rem; border: 1px solid var(--border); text-align: left; }
.article th { background: var(--bg-alt); font-weight: 700; }
.article tr:hover td { background: var(--accent-l); }

/* ---- CTA SECTION ---- */
.cta-section {
  background: var(--gradient-hero); border-radius: var(--radius-lg);
  padding: 3.5rem 2.5rem; text-align: center; color: #fff;
  position: relative; overflow: hidden;
  margin: 2rem 0;
}
.cta-section::before {
  content: ""; position: absolute; inset: 0;
  background: radial-gradient(circle 300px at 30% 50%, rgba(34,211,238,.15) 0%, transparent 70%);
  pointer-events: none;
}
.cta-section h2 { color: #fff; margin-bottom: .75rem; position: relative; z-index: 1; }
.cta-section p  { color: rgba(255,255,255,.75); max-width: 500px; margin: 0 auto 1.5rem; position: relative; z-index: 1; }
.cta-section .btn { position: relative; z-index: 1; }

/* ---- FOOTER ---- */
.footer {
  background: var(--card); border-top: 1px solid var(--border);
  padding: 3.5rem 0 1.5rem; margin-top: auto;
}
.footer__grid {
  display: grid; grid-template-columns: 1.5fr repeat(3, 1fr); gap: 2.5rem;
  margin-bottom: 2.5rem;
}
@media (max-width: 768px) { .footer__grid { grid-template-columns: 1fr 1fr; } }
@media (max-width: 480px) { .footer__grid { grid-template-columns: 1fr; } }
.footer__brand p { font-size: .88rem; color: var(--muted); margin-top: .5rem; line-height: 1.65; }
.footer__col h4 {
  font-size: .8rem; text-transform: uppercase; letter-spacing: .07em;
  color: var(--muted-2); margin-bottom: .85rem; font-weight: 700;
}
.footer__col ul { list-style: none; padding: 0; }
.footer__col li { margin-bottom: .45rem; }
.footer__col a {
  color: var(--muted); font-size: .88rem; font-weight: 500;
  transition: color .2s var(--ease);
}
.footer__col a:hover { color: var(--accent); }
.footer__bottom {
  border-top: 1px solid var(--border); padding-top: 1.5rem;
  text-align: center; font-size: .82rem; color: var(--muted-2);
}

/* ---- ADS ---- */
.ad-slot {
  background: var(--bg-alt); border: 1px dashed var(--border);
  border-radius: var(--radius-sm); min-height: 90px;
  display: flex; align-items: center; justify-content: center;
  margin: 2rem 0; overflow: hidden;
}

/* ---- BADGES ---- */
.badge {
  display: inline-flex; align-items: center; gap: .25rem;
  padding: .25rem .7rem; border-radius: 99px;
  font-size: .73rem; font-weight: 700; letter-spacing: .02em;
}
.badge--accent  { background: var(--accent-l); color: var(--accent); }
.badge--accent2 { background: var(--warn-l); color: var(--accent2); }
.badge--success { background: var(--success-l); color: var(--success); }
.badge--warn    { background: var(--warn-l); color: var(--warn); }

/* ---- CONTACT FORM ---- */
.contact-form { max-width: 560px; }
.contact-form textarea { min-height: 140px; resize: vertical; }

/* ---- COOKIE BANNER ---- */
.cookie-banner {
  position: fixed; bottom: 0; left: 0; right: 0; z-index: 999;
  background: var(--card-glass);
  -webkit-backdrop-filter: blur(16px) saturate(1.5);
  backdrop-filter: blur(16px) saturate(1.5);
  border-top: 1px solid var(--border);
  padding: 1.1rem 1.5rem; box-shadow: 0 -8px 30px rgba(0,0,0,.08);
  display: none; align-items: center; justify-content: space-between;
  gap: 1rem; flex-wrap: wrap;
}
.cookie-banner.show { display: flex; animation: fadeInUp .3s var(--ease); }
.cookie-banner p { font-size: .85rem; color: var(--muted); margin: 0; }
.cookie-banner .btn { flex-shrink: 0; }

/* ---- SCROLL TO TOP ---- */
.scroll-top {
  position: fixed; bottom: 2rem; right: 2rem; z-index: 90;
  width: 44px; height: 44px; border-radius: 50%;
  background: var(--accent); color: #fff; border: none;
  cursor: pointer; display: none; align-items: center; justify-content: center;
  box-shadow: var(--shadow-accent);
  transition: all .3s var(--ease);
}
.scroll-top.show { display: flex; animation: scaleIn .3s var(--ease-spring); }
.scroll-top:hover { transform: translateY(-3px) scale(1.08); }
.scroll-top svg { width: 20px; height: 20px; }

/* ---- UTILITY ---- */
.text-center { text-align: center; }
.text-muted  { color: var(--muted); }
.text-sm     { font-size: .88rem; }
.text-xs     { font-size: .82rem; }
.text-accent { color: var(--accent); }
.text-gradient {
  background: var(--gradient-accent); -webkit-background-clip: text;
  -webkit-text-fill-color: transparent; background-clip: text;
}
.mt-1 { margin-top: .5rem; }
.mt-2 { margin-top: 1rem; }
.mt-3 { margin-top: 1.5rem; }
.mt-4 { margin-top: 2rem; }
.mb-1 { margin-bottom: .5rem; }
.mb-2 { margin-bottom: 1rem; }
.mb-3 { margin-bottom: 1.5rem; }
.hidden { display: none !important; }
.sr-only {
  position: absolute; width: 1px; height: 1px;
  padding: 0; margin: -1px; overflow: hidden;
  clip: rect(0,0,0,0); border: 0;
}

/* ---- PRINT ---- */
@media print {
  .header, .footer, .ad-slot, .cookie-banner, .btn-group, .scroll-top,
  .hamburger, .header__actions, .theme-toggle, .trust-strip,
  .hero::after { display: none !important; }
  body { background: #fff; color: #000; }
  .hero { background: #0891b2 !important; -webkit-print-color-adjust: exact; print-color-adjust: exact; }
  .card, .result-panel, .interp-card { box-shadow: none; border: 1px solid #ccc; }
  .result-panel { -webkit-print-color-adjust: exact; print-color-adjust: exact; }
  .disclaimer { -webkit-print-color-adjust: exact; print-color-adjust: exact; }
  .article { max-width: 100%; }
}