/* ==========================================================================
   ShapeCalculator — global styles
   Design tokens, base typography, layout, header, footer, shared components.
   ========================================================================== */

:root {
  --bg: #f6f6fb;
  --bg-soft: #eeedf8;
  --surface: #ffffff;
  --surface-2: #f9f9fd;
  --border: #e3e2f0;
  --border-strong: #cfcde3;
  --text: #17162b;
  --text-2: #4b4a66;
  --text-3: #75748f;
  --primary: #5b45e0;
  --primary-600: #4a35cc;
  --primary-050: #efecff;
  --primary-100: #e0dbff;
  --accent: #ff6f61;
  --accent-050: #fff0ee;
  --good: #16a36a;
  --good-050: #e5f7ef;
  --ok: #2f80ed;
  --ok-050: #e8f1fd;
  --warn: #e39a0b;
  --warn-050: #fdf4e1;
  --bad: #e2463c;
  --bad-050: #fdeceb;
  --shadow-sm: 0 1px 2px rgba(23, 22, 43, .06);
  --shadow: 0 1px 2px rgba(23, 22, 43, .05), 0 8px 24px -8px rgba(40, 30, 120, .14);
  --shadow-lg: 0 24px 60px -20px rgba(40, 30, 120, .28);
  --radius-sm: 10px;
  --radius: 16px;
  --radius-lg: 24px;
  --container: 1180px;
  --gutter: clamp(16px, 4vw, 32px);
  --font: ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", sans-serif;
  --font-display: ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  color-scheme: light;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #0f0e1a;
    --bg-soft: #17162a;
    --surface: #181729;
    --surface-2: #1e1d33;
    --border: #2c2a46;
    --border-strong: #3b3960;
    --text: #f1f0fa;
    --text-2: #c3c1dc;
    --text-3: #9391b2;
    --primary: #8f7dff;
    --primary-600: #a497ff;
    --primary-050: #231f45;
    --primary-100: #2e2860;
    --accent: #ff8a7e;
    --accent-050: #3a1f22;
    --good: #3ccf8e;
    --good-050: #10291f;
    --ok: #5ea1ff;
    --ok-050: #13233b;
    --warn: #f3b33d;
    --warn-050: #2e2410;
    --bad: #ff6b61;
    --bad-050: #331716;
    --shadow: 0 1px 2px rgba(0, 0, 0, .4), 0 8px 24px -8px rgba(0, 0, 0, .5);
    --shadow-lg: 0 24px 60px -20px rgba(0, 0, 0, .7);
    color-scheme: dark;
  }
}

:root[data-theme="dark"] {
  --bg: #0f0e1a;
  --bg-soft: #17162a;
  --surface: #181729;
  --surface-2: #1e1d33;
  --border: #2c2a46;
  --border-strong: #3b3960;
  --text: #f1f0fa;
  --text-2: #c3c1dc;
  --text-3: #9391b2;
  --primary: #8f7dff;
  --primary-600: #a497ff;
  --primary-050: #231f45;
  --primary-100: #2e2860;
  --accent: #ff8a7e;
  --accent-050: #3a1f22;
  --good: #3ccf8e;
  --good-050: #10291f;
  --ok: #5ea1ff;
  --ok-050: #13233b;
  --warn: #f3b33d;
  --warn-050: #2e2410;
  --bad: #ff6b61;
  --bad-050: #331716;
  --shadow: 0 1px 2px rgba(0, 0, 0, .4), 0 8px 24px -8px rgba(0, 0, 0, .5);
  --shadow-lg: 0 24px 60px -20px rgba(0, 0, 0, .7);
  color-scheme: dark;
}

/* ---------- Reset & base ---------- */
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation-duration: .01ms !important; transition-duration: .01ms !important; }
}
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  font-size: 16px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}
img, svg { max-width: 100%; display: block; }
a { color: var(--primary); text-underline-offset: 3px; }
a:hover { color: var(--primary-600); }
h1, h2, h3, h4 { font-family: var(--font-display); line-height: 1.2; margin: 0 0 .5em; letter-spacing: -.02em; color: var(--text); }
h1 { font-size: clamp(2rem, 4.6vw, 3.1rem); font-weight: 800; letter-spacing: -.035em; }
h2 { font-size: clamp(1.45rem, 2.6vw, 1.9rem); font-weight: 750; }
h3 { font-size: 1.15rem; font-weight: 700; }
p { margin: 0 0 1em; }
ul, ol { padding-left: 1.2em; }
button, input, select, textarea { font: inherit; color: inherit; }
:focus-visible { outline: 3px solid var(--primary); outline-offset: 2px; border-radius: 6px; }
::selection { background: var(--primary-100); }

.container { width: 100%; max-width: var(--container); margin-inline: auto; padding-inline: var(--gutter); }
.visually-hidden { position: absolute !important; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; border: 0; }

.skip-link {
  position: absolute; left: 12px; top: -60px; z-index: 100;
  background: var(--primary); color: #fff; padding: 10px 16px; border-radius: 10px; font-weight: 600; text-decoration: none;
}
.skip-link:focus { top: 12px; color: #fff; }

/* ---------- Header ---------- */
.site-header {
  position: sticky; top: 0; z-index: 50;
  background: color-mix(in srgb, var(--bg) 82%, transparent);
  backdrop-filter: saturate(160%) blur(14px);
  -webkit-backdrop-filter: saturate(160%) blur(14px);
  border-bottom: 1px solid var(--border);
}
.header-inner { display: flex; align-items: center; gap: 16px; height: 66px; }
.logo { display: inline-flex; align-items: center; gap: 10px; text-decoration: none; color: var(--text); font-weight: 800; font-size: 1.12rem; letter-spacing: -.02em; }
.logo:hover { color: var(--text); }
.logo-mark { width: 34px; height: 34px; flex: none; }
.logo span b { color: var(--primary); font-weight: 800; }

.main-nav { margin-left: auto; display: flex; align-items: center; gap: 4px; }
.main-nav > a, .nav-trigger {
  display: inline-flex; align-items: center; gap: 6px;
  padding: 8px 12px; border-radius: 10px; border: 0; background: none; cursor: pointer;
  color: var(--text-2); font-weight: 600; font-size: .95rem; text-decoration: none;
}
.main-nav > a:hover, .nav-trigger:hover, .nav-trigger[aria-expanded="true"] { background: var(--primary-050); color: var(--primary); }
.main-nav > a[aria-current="page"] { color: var(--primary); }
.nav-trigger svg { width: 14px; height: 14px; transition: transform .2s; }
.nav-trigger[aria-expanded="true"] svg { transform: rotate(180deg); }

.nav-item { position: relative; }
.mega {
  position: absolute; right: 0; top: calc(100% + 10px);
  width: min(760px, calc(100vw - 32px));
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg); padding: 22px;
  display: grid; grid-template-columns: repeat(4, 1fr); gap: 18px;
  opacity: 0; visibility: hidden; transform: translateY(-6px); transition: .18s ease;
}
.mega.is-open { opacity: 1; visibility: visible; transform: none; }
.mega .mega-title { font-size: .74rem; font-weight: 700; text-transform: uppercase; letter-spacing: .08em; color: var(--text-3); margin: 0 0 8px; }
.mega ul { list-style: none; margin: 0; padding: 0; }
.mega a { display: block; padding: 6px 8px; margin-inline: -8px; border-radius: 8px; color: var(--text); text-decoration: none; font-size: .92rem; font-weight: 500; }
.mega a:hover { background: var(--primary-050); color: var(--primary); }

.icon-btn {
  width: 40px; height: 40px; display: inline-grid; place-items: center; flex: none;
  border-radius: 12px; border: 1px solid var(--border); background: var(--surface); color: var(--text-2); cursor: pointer;
}
.icon-btn:hover { color: var(--primary); border-color: var(--primary-100); }
.icon-btn svg { width: 19px; height: 19px; }
.theme-toggle .moon { display: none; }
:root[data-theme="dark"] .theme-toggle .sun { display: none; }
:root[data-theme="dark"] .theme-toggle .moon { display: block; }
.menu-toggle { display: none; }

@media (max-width: 860px) {
  .menu-toggle { display: inline-grid; }
  .main-nav {
    position: fixed; inset: 66px 0 auto 0; max-height: calc(100vh - 66px); overflow-y: auto;
    flex-direction: column; align-items: stretch; gap: 2px;
    background: var(--surface); border-bottom: 1px solid var(--border); box-shadow: var(--shadow-lg);
    padding: 12px var(--gutter) 20px;
    transform: translateY(-8px); opacity: 0; visibility: hidden; transition: .18s ease;
  }
  .main-nav.is-open { transform: none; opacity: 1; visibility: visible; }
  .main-nav > a, .nav-trigger { width: 100%; justify-content: space-between; padding: 12px; }
  .mega { position: static; width: 100%; box-shadow: none; border: 0; padding: 4px 12px 12px; grid-template-columns: 1fr 1fr; display: none; opacity: 1; visibility: visible; transform: none; }
  .mega.is-open { display: grid; }
  .header-actions { margin-left: auto; }
}
@media (max-width: 480px) { .mega { grid-template-columns: 1fr; } }
.header-actions { display: flex; gap: 8px; }

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  min-height: 48px; padding: 12px 22px; border-radius: 14px; border: 1px solid transparent;
  font-weight: 700; font-size: 1rem; cursor: pointer; text-decoration: none; transition: transform .12s, box-shadow .2s, background .2s;
}
.btn:active { transform: translateY(1px); }
.btn svg { width: 18px; height: 18px; }
.btn-primary { background: linear-gradient(135deg, var(--primary), #7a5cff); color: #fff; box-shadow: 0 8px 20px -8px rgba(91, 69, 224, .7); }
.btn-primary:hover { color: #fff; box-shadow: 0 12px 26px -8px rgba(91, 69, 224, .8); }
.btn-ghost { background: var(--surface); border-color: var(--border); color: var(--text-2); }
.btn-ghost:hover { border-color: var(--primary-100); color: var(--primary); }
.btn-sm { min-height: 38px; padding: 8px 14px; font-size: .9rem; border-radius: 11px; }

/* ---------- Breadcrumb ---------- */
.breadcrumb { padding-top: 18px; }
.breadcrumb ol { list-style: none; display: flex; flex-wrap: wrap; gap: 6px; margin: 0; padding: 0; font-size: .86rem; color: var(--text-3); }
.breadcrumb li + li::before { content: "/"; margin-right: 6px; color: var(--border-strong); }
.breadcrumb a { color: var(--text-3); text-decoration: none; }
.breadcrumb a:hover { color: var(--primary); }

/* ---------- Sections ---------- */
.section { padding-block: clamp(40px, 6vw, 72px); }
.section-head { max-width: 720px; margin-bottom: 28px; }
.section-head p { color: var(--text-2); font-size: 1.05rem; }
.eyebrow {
  display: inline-flex; align-items: center; gap: 8px; margin: 0 0 12px;
  font-size: .78rem; font-weight: 700; text-transform: uppercase; letter-spacing: .1em; color: var(--primary);
}
.eyebrow::before { content: ""; width: 18px; height: 2px; background: currentColor; border-radius: 2px; }
.lead { font-size: clamp(1.05rem, 1.6vw, 1.2rem); color: var(--text-2); max-width: 680px; }

.card { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius-lg); box-shadow: var(--shadow); }

/* ---------- Calculator cards grid (home + related) ---------- */
.tool-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(250px, 1fr)); gap: 16px; }
.tool-card {
  position: relative; display: flex; flex-direction: column; gap: 10px;
  padding: 20px; border-radius: var(--radius); background: var(--surface); border: 1px solid var(--border);
  text-decoration: none; color: var(--text); box-shadow: var(--shadow-sm);
  transition: transform .18s ease, box-shadow .18s ease, border-color .18s;
}
.tool-card:hover { transform: translateY(-3px); box-shadow: var(--shadow); border-color: var(--primary-100); color: var(--text); }
.tool-card h3 { margin: 0; font-size: 1.04rem; }
.tool-card p { margin: 0; color: var(--text-2); font-size: .92rem; line-height: 1.5; }
.tool-icon { width: 44px; height: 44px; border-radius: 12px; display: grid; place-items: center; background: var(--primary-050); color: var(--primary); }
.tool-icon svg { width: 24px; height: 24px; }
.tool-card .arrow { margin-top: auto; font-size: .88rem; font-weight: 700; color: var(--primary); }
.tool-card[hidden] { display: none; }
.tag-row { display: flex; flex-wrap: wrap; gap: 6px; }
.tag { font-size: .72rem; font-weight: 700; padding: 3px 9px; border-radius: 999px; background: var(--bg-soft); color: var(--text-2); }

/* ---------- FAQ ---------- */
.faq { display: grid; gap: 10px; max-width: 860px; }
.faq details { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 0 20px; }
.faq summary {
  list-style: none; cursor: pointer; padding: 18px 32px 18px 0; position: relative; font-weight: 700; font-size: 1.02rem;
}
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after {
  content: ""; position: absolute; right: 2px; top: 50%; width: 10px; height: 10px; margin-top: -7px;
  border-right: 2px solid var(--text-3); border-bottom: 2px solid var(--text-3); transform: rotate(45deg); transition: transform .2s;
}
.faq details[open] summary::after { transform: rotate(-135deg); margin-top: -2px; }
.faq details > div { padding: 0 0 18px; color: var(--text-2); }
.faq details > div p:last-child { margin-bottom: 0; }

/* ---------- Prose / info blocks ---------- */
.info-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); gap: 16px; }
.info-card { padding: 22px; background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); }
.info-card h3 { display: flex; align-items: center; gap: 10px; }
.info-card p, .info-card li { color: var(--text-2); font-size: .96rem; }
.info-card p:last-child, .info-card ul:last-child, .info-card ol:last-child { margin-bottom: 0; }
.step-num { width: 28px; height: 28px; border-radius: 50%; display: inline-grid; place-items: center; background: var(--primary); color: #fff; font-size: .85rem; font-weight: 800; flex: none; }
.formula {
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace; font-size: .86rem;
  background: var(--surface-2); border: 1px dashed var(--border-strong); border-radius: 10px; padding: 10px 12px; color: var(--text); overflow-x: auto;
}
.disclaimer { font-size: .88rem; color: var(--text-3); border-left: 3px solid var(--border-strong); padding-left: 12px; max-width: 860px; }

.data-table { width: 100%; border-collapse: collapse; font-size: .93rem; }
.table-wrap { overflow-x: auto; border: 1px solid var(--border); border-radius: var(--radius); background: var(--surface); }
.data-table th, .data-table td { padding: 11px 14px; text-align: left; border-bottom: 1px solid var(--border); white-space: nowrap; }
.data-table th { background: var(--surface-2); font-size: .78rem; text-transform: uppercase; letter-spacing: .06em; color: var(--text-3); }
.data-table tr:last-child td { border-bottom: 0; }

/* ---------- Footer ---------- */
.site-footer { margin-top: 40px; border-top: 1px solid var(--border); background: var(--surface); }
.footer-grid { display: grid; grid-template-columns: 1.3fr repeat(5, 1fr); gap: 28px; padding-block: 48px 28px; }
.footer-grid h2 { font-size: .78rem; text-transform: uppercase; letter-spacing: .08em; color: var(--text-3); margin-bottom: 12px; }
.footer-grid ul { list-style: none; padding: 0; margin: 0; display: grid; gap: 7px; }
.footer-grid > * { min-width: 0; }
.footer-grid a { overflow-wrap: anywhere; color: var(--text-2); text-decoration: none; font-size: .92rem; }
.footer-grid a:hover { color: var(--primary); }
.footer-about p { color: var(--text-2); font-size: .93rem; max-width: 300px; margin-top: 12px; }
.footer-bottom { display: flex; flex-wrap: wrap; justify-content: space-between; gap: 12px; padding-block: 18px 28px; border-top: 1px solid var(--border); color: var(--text-3); font-size: .85rem; }
@media (max-width: 900px) { .footer-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); } .footer-about { grid-column: 1 / -1; } }

/* ---------- Home hero ---------- */
.home-hero, .calc-hero { isolation: isolate; }
.home-hero { position: relative; padding-block: clamp(48px, 8vw, 96px) 40px; }
html { overflow-x: clip; }
.home-hero::before, .calc-hero::before {
  content: ""; position: absolute; inset: -40% -10% auto auto; width: 620px; height: 620px; z-index: -1;
  background: radial-gradient(closest-side, rgba(122, 92, 255, .22), transparent);
  pointer-events: none;
}
.home-hero::after {
  content: ""; position: absolute; left: -200px; bottom: -260px; width: 560px; height: 560px; z-index: -1;
  background: radial-gradient(closest-side, rgba(255, 111, 97, .14), transparent); pointer-events: none;
}
.home-hero h1 { max-width: 820px; }
.home-hero h1 em { font-style: normal; background: linear-gradient(90deg, var(--primary), var(--accent)); -webkit-background-clip: text; background-clip: text; color: transparent; }
.search-box { position: relative; max-width: 560px; margin-top: 28px; }
.search-box svg { position: absolute; left: 16px; top: 50%; transform: translateY(-50%); width: 20px; height: 20px; color: var(--text-3); }
.search-box input {
  width: 100%; height: 56px; padding: 0 18px 0 48px; border-radius: 16px; border: 1px solid var(--border-strong);
  background: var(--surface); box-shadow: var(--shadow); font-size: 1.02rem;
}
.search-box input:focus { outline: none; border-color: var(--primary); box-shadow: 0 0 0 4px var(--primary-050), var(--shadow); }
.stats-row { display: flex; flex-wrap: wrap; gap: 28px; margin-top: 32px; }
.stats-row div { display: grid; }
.stats-row strong { font-size: 1.6rem; font-weight: 800; letter-spacing: -.03em; }
.stats-row span { color: var(--text-3); font-size: .9rem; }
.cat-title { display: flex; align-items: center; gap: 10px; margin: 36px 0 16px; font-size: 1.2rem; }
.cat-title:first-child { margin-top: 0; }
.empty-state { padding: 24px; text-align: center; color: var(--text-3); border: 1px dashed var(--border-strong); border-radius: var(--radius); }

/* ---------- Language switcher ---------- */
.lang-switch { position: relative; }
.lang-trigger { width: auto; padding: 0 10px; gap: 6px; display: inline-flex; align-items: center; }
.lang-code { font-size: .78rem; font-weight: 800; letter-spacing: .04em; }
.lang-menu {
  position: absolute; inset-inline-end: 0; top: calc(100% + 8px); z-index: 60; min-width: 190px;
  list-style: none; margin: 0; padding: 8px; display: grid; gap: 2px;
  background: var(--surface); border: 1px solid var(--border); border-radius: 14px; box-shadow: var(--shadow-lg);
  opacity: 0; visibility: hidden; transform: translateY(-6px); transition: .16s ease;
}
.lang-switch.is-open .lang-menu { opacity: 1; visibility: visible; transform: none; }
.lang-menu a { display: block; padding: 8px 12px; border-radius: 9px; color: var(--text); text-decoration: none; font-size: .92rem; font-weight: 550; }
.lang-menu a:hover { background: var(--primary-050); color: var(--primary); }
.lang-menu a[aria-current="true"] { color: var(--primary); font-weight: 750; }
@media (max-width: 480px) { .lang-code { display: none; } .lang-trigger { padding: 0; width: 40px; justify-content: center; } }

/* ---------- Right-to-left (Arabic) ---------- */
[dir="rtl"] body { font-family: "Segoe UI", Tahoma, "Noto Sans Arabic", Arial, sans-serif; }
[dir="rtl"] .eyebrow::before { order: 2; }
[dir="rtl"] .breadcrumb li + li::before { margin-right: 0; margin-left: 6px; }
[dir="rtl"] .faq summary { padding: 18px 0 18px 32px; }
[dir="rtl"] .faq summary::after { right: auto; left: 2px; }
[dir="rtl"] .search-box svg { left: auto; right: 16px; }
[dir="rtl"] .search-box input { padding: 0 48px 0 18px; }
[dir="rtl"] .dir-icon, [dir="rtl"] .tool-card .arrow { transform: scaleX(-1); display: inline-block; }
[dir="rtl"] .disclaimer { border-left: 0; border-right: 3px solid var(--border-strong); padding-left: 0; padding-right: 12px; }
[dir="rtl"] .mega { right: auto; left: 0; }