/* ==========================================================================
   MATHS SOLVER — CORE STYLESHEET
   Design language: "Working Page" — a digital notebook / graph-paper desk.
   Palette: deep indigo ink, electric blue + violet accents, amber "solved" mark.
   Type: Space Grotesk (display), Inter (body), JetBrains Mono (equations/data)
   ========================================================================== */

/* ---------- Design Tokens ---------- */
:root {
  /* Lock to light scheme so browser/OS dark mode never auto-recolors
     native form controls (inputs, selects) to invisible/mismatched text */
  color-scheme: light;

  /* Colors */
  --color-bg: #F6F7FC;
  --color-bg-alt: #EBEDF9;
  --color-paper: #FFFFFF;
  --color-ink: #130F2A;
  --color-ink-soft: #4C4768;
  --color-ink-faint: #85819D;
  --color-indigo: #2B2470;
  --color-indigo-deep: #0F0C29;
  --color-blue: #3E63FF;
  --color-blue-soft: #E6EBFF;
  --color-violet: #9333EA;
  --color-violet-soft: #F3E7FE;
  --color-amber: #FDB022;
  --color-amber-soft: #FFF3DC;
  --color-line: #E2E1F1;
  --color-white: #FFFFFF;
  --color-success: #16A34A;

  /* Gradients */
  --gradient-brand: linear-gradient(135deg, var(--color-blue) 0%, var(--color-violet) 100%);
  --gradient-hero: linear-gradient(160deg, #0F0C29 0%, #2B2470 42%, #6D28D9 100%);
  --gradient-amber: linear-gradient(135deg, #FDB022 0%, #F2711D 100%);

  /* Typography */
  --font-display: 'Space Grotesk', 'Segoe UI', sans-serif;
  --font-body: 'Inter', 'Segoe UI', sans-serif;
  --font-mono: 'JetBrains Mono', 'Consolas', monospace;

  /* Spacing scale */
  --space-xs: 0.5rem;
  --space-sm: 1rem;
  --space-md: 1.5rem;
  --space-lg: 2.5rem;
  --space-xl: 4rem;
  --space-2xl: 6rem;

  /* Radius & shadow */
  --radius-sm: 10px;
  --radius-md: 16px;
  --radius-lg: 24px;
  --radius-full: 999px;
  --shadow-sm: 0 2px 8px rgba(23, 19, 48, 0.06);
  --shadow-md: 0 8px 24px rgba(23, 19, 48, 0.10);
  --shadow-lg: 0 20px 48px rgba(23, 19, 48, 0.16);
  --shadow-glow: 0 0 0 1px rgba(62, 99, 255, 0.12), 0 12px 32px rgba(62, 99, 255, 0.18);

  /* Layout */
  --container-w: 1240px;
  --header-h: 76px;
}

/* ---------- Reset ---------- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
    scroll-behavior: auto !important;
  }
}

body {
  font-family: var(--font-body);
  color: var(--color-ink);
  background: var(--color-bg);
  line-height: 1.6;
  overflow-x: hidden;
  background-image:
    linear-gradient(var(--color-line) 1px, transparent 1px),
    linear-gradient(90deg, var(--color-line) 1px, transparent 1px);
  background-size: 40px 40px;
  background-position: -1px -1px;
}

img { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
ul { list-style: none; }
button { font-family: inherit; cursor: pointer; border: none; background: none; }
input, textarea, select {
  font-family: inherit;
  font-size: 1rem;
  color: var(--color-ink);
  background-color: var(--color-white);
  accent-color: var(--color-blue);
}
::placeholder { color: var(--color-ink-faint); opacity: 1; }

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-display);
  color: var(--color-indigo-deep);
  line-height: 1.15;
  font-weight: 700;
  letter-spacing: -0.01em;
}

.mono, .equation, code { font-family: var(--font-mono); }

:focus-visible {
  outline: 2px solid var(--color-blue);
  outline-offset: 3px;
  border-radius: 4px;
}

/* ---------- Layout helpers ---------- */
.container {
  width: 100%;
  max-width: var(--container-w);
  margin-inline: auto;
  padding-inline: var(--space-md);
}

section { position: relative; padding-block: var(--space-2xl); }
section.tight { padding-block: var(--space-xl); }

.section-head {
  max-width: 720px;
  margin-inline: auto;
  text-align: center;
  margin-bottom: var(--space-xl);
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 0.78rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--color-blue);
  background: var(--color-blue-soft);
  padding: 6px 14px;
  border-radius: var(--radius-full);
  margin-bottom: var(--space-sm);
}

.section-head h2 {
  font-size: clamp(1.8rem, 3.2vw, 2.6rem);
  margin-bottom: var(--space-sm);
}

.section-head p {
  color: var(--color-ink-soft);
  font-size: 1.05rem;
}

.section-alt { background: var(--color-bg-alt); }

.grid {
  display: grid;
  gap: var(--space-md);
}
.grid-2 { grid-template-columns: repeat(2, 1fr); }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-4 { grid-template-columns: repeat(4, 1fr); }
.grid-6 { grid-template-columns: repeat(6, 1fr); }

/* ---------- Buttons ---------- */
.btn {
  position: relative;
  overflow: hidden;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 14px 28px;
  border-radius: var(--radius-full);
  font-weight: 600;
  font-size: 0.98rem;
  transition: transform 0.25s ease, box-shadow 0.25s ease, background 0.25s ease;
  white-space: nowrap;
}
.btn:active { transform: scale(0.97); }

.btn-primary {
  background: var(--gradient-brand);
  color: var(--color-white);
  box-shadow: var(--shadow-glow);
}
.btn-primary:hover { transform: translateY(-3px); box-shadow: 0 16px 36px rgba(62, 99, 255,0.28); }

.btn-secondary {
  background: var(--color-white);
  color: var(--color-indigo);
  border: 1.5px solid var(--color-line);
}
.btn-secondary:hover { border-color: var(--color-blue); color: var(--color-blue); transform: translateY(-3px); }

.btn-amber {
  background: var(--gradient-amber);
  color: var(--color-white);
  box-shadow: 0 10px 26px rgba(242, 113, 29,0.28);
}
.btn-amber:hover { transform: translateY(-3px); }

.btn-block { width: 100%; }
.btn-sm { padding: 10px 20px; font-size: 0.88rem; }

/* ripple */
.btn .ripple {
  position: absolute;
  border-radius: 50%;
  background: rgba(255,255,255,0.55);
  transform: scale(0);
  animation: ripple-anim 0.6s linear;
  pointer-events: none;
}
@keyframes ripple-anim {
  to { transform: scale(3); opacity: 0; }
}

/* ---------- Header ---------- */
.site-header {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 1000;
  height: var(--header-h);
  display: flex;
  align-items: center;
  background: rgba(247, 247, 251, 0.72);
  backdrop-filter: blur(14px) saturate(160%);
  -webkit-backdrop-filter: blur(14px) saturate(160%);
  border-bottom: 1px solid transparent;
  transition: border-color 0.3s ease, box-shadow 0.3s ease, background 0.3s ease;
}
.site-header.is-scrolled {
  border-bottom-color: var(--color-line);
  box-shadow: var(--shadow-sm);
  background: rgba(247, 247, 251, 0.92);
}

.navbar { width: 100%; display: flex; align-items: center; justify-content: space-between; gap: var(--space-md); }

.brand { display: flex; align-items: center; gap: 10px; font-family: var(--font-display); font-weight: 700; font-size: 1.25rem; color: var(--color-indigo-deep); }
.brand-mark {
  width: 38px; height: 38px; border-radius: 11px;
  background: var(--gradient-brand);
  display: flex; align-items: center; justify-content: center;
  color: #fff; font-family: var(--font-mono); font-weight: 700; font-size: 1.1rem;
  box-shadow: var(--shadow-glow);
}

.nav-menu { display: flex; align-items: center; gap: var(--space-lg); }
.nav-menu a {
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--color-ink-soft);
  position: relative;
  padding-block: 6px;
  transition: color 0.2s ease;
}
.nav-menu a::after {
  content: "";
  position: absolute; left: 0; right: 0; bottom: 0;
  height: 2px; background: var(--gradient-brand);
  transform: scaleX(0); transform-origin: left;
  transition: transform 0.25s ease;
}
.nav-menu a:hover { color: var(--color-indigo-deep); }
.nav-menu a:hover::after, .nav-menu a.active::after { transform: scaleX(1); }
.nav-menu a.active { color: var(--color-blue); }

.nav-actions { display: flex; align-items: center; gap: var(--space-sm); }

.hamburger {
  display: none;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 5px;
  width: 44px;
  height: 44px;
  padding: 0;
}
.hamburger span {
  width: 26px;
  height: 2px; background: var(--color-indigo-deep); border-radius: 2px;
  transition: transform 0.3s ease, opacity 0.3s ease;
}
.hamburger.is-active span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.hamburger.is-active span:nth-child(2) { opacity: 0; }
.hamburger.is-active span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

.scroll-progress {
  position: fixed; top: 0; left: 0; height: 3px;
  background: var(--gradient-brand);
  z-index: 1001; width: 0%;
  transition: width 0.1s linear;
}

/* ---------- Hero ---------- */
.hero {
  position: relative;
  padding-top: calc(var(--header-h) + 4.5rem);
  padding-bottom: var(--space-2xl);
  background: var(--gradient-hero);
  color: #fff;
  overflow: hidden;
}
.hero::before {
  content: "";
  position: absolute; inset: 0;
  background-image: radial-gradient(rgba(255,255,255,0.09) 1px, transparent 1px);
  background-size: 26px 26px;
  opacity: 0.5;
}
.hero-inner {
  position: relative;
  display: grid;
  grid-template-columns: 1.05fr 0.95fr;
  gap: var(--space-xl);
  align-items: center;
}
.hero-eyebrow {
  display: inline-flex; align-items: center; gap: 8px;
  font-family: var(--font-mono); font-size: 0.78rem; letter-spacing: 0.1em;
  text-transform: uppercase; color: #C9D0FF;
  background: rgba(255,255,255,0.08); border: 1px solid rgba(255,255,255,0.14);
  padding: 6px 14px; border-radius: var(--radius-full); margin-bottom: var(--space-md);
}
.hero h1 {
  color: #fff;
  font-size: clamp(2.3rem, 4.6vw, 3.6rem);
  margin-bottom: var(--space-md);
}
.hero h1 .accent { color: var(--color-amber); }
.hero p.lead {
  color: #D4D6EE;
  font-size: 1.1rem;
  max-width: 540px;
  margin-bottom: var(--space-lg);
}

.solver-box {
  display: flex;
  gap: 10px;
  background: rgba(255,255,255,0.08);
  border: 1px solid rgba(255,255,255,0.16);
  padding: 8px;
  border-radius: var(--radius-full);
  margin-bottom: var(--space-md);
  backdrop-filter: blur(8px);
}
.solver-box input {
  flex: 1;
  background: transparent;
  border: none;
  color: #fff;
  padding: 12px 18px;
  font-size: 1rem;
  font-family: var(--font-mono);
}
.solver-box input::placeholder { color: #A7ACD9; }

.hero-topics { display: flex; flex-wrap: wrap; gap: 10px; margin-bottom: var(--space-lg); }
.hero-topics span {
  font-size: 0.82rem; color: #D4D6EE;
  border: 1px solid rgba(255,255,255,0.18);
  padding: 6px 14px; border-radius: var(--radius-full);
  transition: background 0.2s ease, color 0.2s ease, border-color .2s ease;
}
.hero-topics span:hover { background: rgba(255,255,255,0.12); color: #fff; border-color: rgba(255,255,255,0.3); }

.hero-ctas { display: flex; gap: 14px; flex-wrap: wrap; }

/* Signature: the notebook equation card */
.equation-card {
  position: relative;
  background: rgba(20, 17, 46, 0.55);
  border: 1px solid rgba(255,255,255,0.14);
  border-radius: var(--radius-lg);
  padding: var(--space-lg);
  backdrop-filter: blur(10px);
  box-shadow: var(--shadow-lg);
}
.equation-card .card-dots { display: flex; gap: 6px; margin-bottom: var(--space-md); }
.equation-card .card-dots span { width: 9px; height: 9px; border-radius: 50%; background: rgba(255,255,255,0.25); }
.equation-card .card-label {
  font-family: var(--font-mono); font-size: 0.78rem; letter-spacing: 0.08em;
  color: #9AA1DE; text-transform: uppercase; margin-bottom: var(--space-sm);
}
.equation-line {
  font-family: var(--font-mono);
  font-size: 1.35rem;
  color: #fff;
  min-height: 2.6em;
  display: flex;
  align-items: center;
}
.equation-line .cursor {
  display: inline-block; width: 2px; height: 1.1em; background: var(--color-amber);
  margin-left: 4px; animation: blink 1s step-end infinite;
}
@keyframes blink { 50% { opacity: 0; } }
.equation-steps { margin-top: var(--space-md); display: flex; flex-direction: column; gap: 8px; }
.equation-steps .step {
  display: flex; align-items: center; gap: 10px;
  font-family: var(--font-mono); font-size: 0.85rem; color: #C4C8EE;
  opacity: 0; transform: translateX(-8px);
}
.equation-steps .step.show { opacity: 1; transform: translateX(0); transition: all .4s ease; }
.equation-steps .step .tick {
  width: 16px; height: 16px; border-radius: 50%; background: var(--color-success);
  display: flex; align-items: center; justify-content: center; font-size: 10px; color: #fff; flex-shrink: 0;
}

.floating-symbols { position: absolute; inset: 0; pointer-events: none; overflow: hidden; }
.floating-symbols span {
  position: absolute;
  font-family: var(--font-mono);
  color: rgba(255,255,255,0.14);
  font-size: 2.2rem;
  animation: floatSym 12s ease-in-out infinite;
}

/* ---------- Cards ---------- */
.card {
  background: var(--color-paper);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-md);
  padding: var(--space-md);
  box-shadow: var(--shadow-sm);
  transition: transform 0.3s ease, box-shadow 0.3s ease, border-color 0.3s ease;
}
.card:hover { transform: translateY(-6px); box-shadow: var(--shadow-md); border-color: rgba(62, 99, 255,0.25); }

.icon-tile {
  width: 52px; height: 52px;
  border-radius: 14px;
  display: flex; align-items: center; justify-content: center;
  background: var(--gradient-brand);
  color: #fff;
  margin-bottom: var(--space-sm);
  font-size: 1.3rem;
  box-shadow: var(--shadow-glow);
}
.icon-tile.alt { background: var(--gradient-amber); box-shadow: 0 10px 26px rgba(242, 113, 29,0.22); }
.icon-tile.soft { background: var(--color-blue-soft); color: var(--color-blue); box-shadow: none; }

.solver-card h3, .calc-card h3, .topic-card h3, .type-card h3 { font-size: 1.08rem; margin-bottom: 6px; }
.solver-card p, .calc-card p, .why-card p { color: var(--color-ink-soft); font-size: 0.92rem; }

.solver-card, .calc-card { cursor: pointer; }
.card-link {
  display: inline-flex; align-items: center; gap: 6px;
  color: var(--color-blue); font-weight: 600; font-size: 0.88rem; margin-top: 10px;
  transition: gap 0.2s ease;
}
.card:hover .card-link { gap: 10px; }

.topic-card {
  text-align: center;
  padding: var(--space-md) var(--space-sm);
}
.topic-card .icon-tile { margin-inline: auto; }

.type-card {
  display: flex; align-items: center; gap: 12px;
  padding: var(--space-sm) var(--space-md);
}
.type-card .dot { width: 8px; height: 8px; border-radius: 50%; background: var(--color-violet); flex-shrink: 0; }

/* ---------- Timeline (Step-by-step + Workflow) ---------- */
.timeline { position: relative; }
.timeline-track {
  display: flex; justify-content: space-between; align-items: flex-start;
  position: relative;
  gap: var(--space-sm);
}
.timeline-track::before {
  content: "";
  position: absolute; top: 26px; left: 4%; right: 4%; height: 2px;
  background: repeating-linear-gradient(90deg, var(--color-line) 0 8px, transparent 8px 14px);
}
.timeline-step { flex: 1; text-align: center; position: relative; }
.timeline-step .node {
  width: 52px; height: 52px; border-radius: 50%;
  background: var(--color-white); border: 2px solid var(--color-blue);
  color: var(--color-blue); font-family: var(--font-mono); font-weight: 700;
  display: flex; align-items: center; justify-content: center;
  margin-inline: auto; margin-bottom: var(--space-sm);
  position: relative; z-index: 2;
  transition: background .3s ease, color .3s ease;
}
.timeline-step:hover .node { background: var(--gradient-brand); color: #fff; }
.timeline-step h4 { font-size: 0.98rem; margin-bottom: 4px; }
.timeline-step p { font-size: 0.85rem; color: var(--color-ink-soft); }

/* ---------- Formula Library ---------- */
.formula-tabs { display: flex; flex-wrap: wrap; gap: 10px; justify-content: center; margin-bottom: var(--space-lg); }
.formula-tab {
  padding: 9px 18px; border-radius: var(--radius-full);
  border: 1.5px solid var(--color-line); font-size: 0.88rem; font-weight: 600;
  color: var(--color-ink-soft); background: var(--color-white);
  transition: all 0.2s ease;
}
.formula-tab.active, .formula-tab:hover { border-color: var(--color-blue); color: var(--color-blue); background: var(--color-blue-soft); }

.formula-card {
  background: var(--color-white); border: 1px solid var(--color-line); border-radius: var(--radius-md);
  padding: var(--space-md); box-shadow: var(--shadow-sm);
}
.formula-card h4 { font-size: 0.95rem; color: var(--color-ink-soft); font-weight: 600; margin-bottom: 10px; }
.formula-card .formula { font-family: var(--font-mono); font-size: 1.05rem; color: var(--color-indigo-deep); background: var(--color-bg-alt); padding: 12px 14px; border-radius: 10px; }
.formula-panel { display: none; }
.formula-panel.active { display: grid; }

/* ---------- Practice ---------- */
.practice-card { text-align: center; position: relative; overflow: hidden; }
.practice-card .badge {
  position: absolute; top: 14px; right: 14px;
  font-size: 0.7rem; font-weight: 700; padding: 4px 10px; border-radius: var(--radius-full);
  text-transform: uppercase; letter-spacing: 0.04em;
}
.badge-easy { background: #E4F8EE; color: var(--color-success); }
.badge-medium { background: var(--color-amber-soft); color: #B9750D; }
.badge-hard { background: #FDE7EA; color: #D8425A; }
.badge-timed, .badge-random { background: var(--color-violet-soft); color: var(--color-violet); }

/* ---------- Stats counters ---------- */
.stats-section {
  background: var(--gradient-hero);
  color: #fff;
}
.stats-grid { display: grid; grid-template-columns: repeat(5, 1fr); gap: var(--space-md); text-align: center; }
.stat .num { font-family: var(--font-mono); font-size: clamp(1.8rem, 3vw, 2.6rem); font-weight: 700; color: var(--color-amber); }
.stat .label { color: #C9CDEE; font-size: 0.9rem; margin-top: 6px; }

/* ---------- Testimonials ---------- */
.testimonial-card { display: flex; flex-direction: column; gap: var(--space-sm); }
.testimonial-quote { color: var(--color-ink-soft); font-size: 0.95rem; }
.testimonial-quote::before { content: "\201C"; color: var(--color-blue); font-size: 1.6rem; font-family: var(--font-display); }
.testimonial-person { display: flex; align-items: center; gap: 10px; margin-top: auto; }
.avatar {
  width: 42px; height: 42px; border-radius: 50%;
  background: var(--gradient-brand); color: #fff;
  display: flex; align-items: center; justify-content: center;
  font-family: var(--font-display); font-weight: 700;
}
.testimonial-person .name { font-weight: 600; font-size: 0.92rem; }
.testimonial-person .role { font-size: 0.8rem; color: var(--color-ink-faint); }

/* ---------- FAQ Accordion ---------- */
.faq-columns { display: grid; grid-template-columns: repeat(2, 1fr); gap: var(--space-md) var(--space-lg); }
.accordion-item {
  background: var(--color-white); border: 1px solid var(--color-line); border-radius: var(--radius-sm);
  overflow: hidden;
}
.accordion-trigger {
  width: 100%; display: flex; align-items: center; justify-content: space-between;
  padding: 16px 18px; font-weight: 600; font-size: 0.95rem; text-align: left; color: var(--color-indigo-deep);
}
.accordion-trigger .icon { flex-shrink: 0; transition: transform 0.3s ease; color: var(--color-blue); font-size: 1.2rem; }
.accordion-item.open .accordion-trigger .icon { transform: rotate(45deg); }
.accordion-panel {
  max-height: 0; overflow: hidden; transition: max-height 0.35s ease;
}
.accordion-panel-inner { padding: 0 18px 16px; color: var(--color-ink-soft); font-size: 0.9rem; }

/* ---------- Contact ---------- */
.contact-grid { display: grid; grid-template-columns: 1fr 1fr; gap: var(--space-xl); align-items: start; }
.form-field { margin-bottom: var(--space-sm); }
.form-field label { display: block; font-size: 0.85rem; font-weight: 600; margin-bottom: 6px; color: var(--color-ink); }
.form-field input, .form-field textarea {
  width: 100%; padding: 13px 16px; border: 1.5px solid var(--color-line); border-radius: var(--radius-sm);
  background: var(--color-white); transition: border-color 0.2s ease, box-shadow 0.2s ease;
}
.form-field input:focus, .form-field textarea:focus {
  border-color: var(--color-blue); box-shadow: 0 0 0 4px var(--color-blue-soft); outline: none;
}
.form-status { font-size: 0.9rem; margin-top: 10px; color: var(--color-success); display: none; }
.form-status.show { display: block; }

.contact-info-item { display: flex; gap: 14px; align-items: flex-start; margin-bottom: var(--space-md); }
.contact-info-item h4 { font-size: 0.98rem; margin-bottom: 3px; }
.contact-info-item p { color: var(--color-ink-soft); font-size: 0.9rem; }
.map-placeholder {
  height: 220px; border-radius: var(--radius-md); border: 1px dashed var(--color-line);
  background: repeating-linear-gradient(45deg, var(--color-bg-alt) 0 10px, var(--color-white) 10px 20px);
  display: flex; align-items: center; justify-content: center; color: var(--color-ink-faint);
  font-size: 0.88rem; margin-top: var(--space-md);
}

/* ---------- Newsletter ---------- */
.newsletter {
  background: var(--gradient-brand);
  border-radius: var(--radius-lg);
  padding: var(--space-xl);
  display: flex; align-items: center; justify-content: space-between; gap: var(--space-lg);
  color: #fff;
  flex-wrap: wrap;
}
.newsletter h3 { color: #fff; font-size: 1.5rem; margin-bottom: 6px; }
.newsletter p { color: #E6E9FF; font-size: 0.95rem; }
.newsletter-form { display: flex; gap: 10px; flex: 1; min-width: 280px; max-width: 420px; }
.newsletter-form input {
  flex: 1; padding: 13px 18px; border-radius: var(--radius-full); border: none;
}

/* ---------- Footer ---------- */
.site-footer { background: var(--color-indigo-deep); color: #C9CDEE; padding-top: var(--space-2xl); }
.footer-grid { display: grid; grid-template-columns: 1.4fr 1fr 1fr 1fr; gap: var(--space-lg); padding-bottom: var(--space-xl); }
.footer-brand p { font-size: 0.9rem; color: #9CA1D6; margin-top: var(--space-sm); max-width: 280px; }
.footer-col h5 { color: #fff; font-size: 0.95rem; margin-bottom: var(--space-sm); }
.footer-col a { display: block; font-size: 0.88rem; color: #A9AEDD; padding-block: 6px; transition: color 0.2s ease; }
.footer-col a:hover { color: var(--color-amber); }
.social-icons { display: flex; gap: 10px; margin-top: var(--space-md); }
.social-icons a {
  width: 38px; height: 38px; border-radius: 50%; background: rgba(255,255,255,0.06);
  display: flex; align-items: center; justify-content: center; font-size: 0.9rem;
  border: 1px solid rgba(255,255,255,0.1); transition: background 0.2s ease, transform .2s ease;
}
.social-icons a:hover { background: var(--gradient-brand); transform: translateY(-3px); }
.footer-bottom {
  border-top: 1px solid rgba(255,255,255,0.08);
  padding-block: var(--space-md);
  display: flex; justify-content: space-between; align-items: center; flex-wrap: wrap; gap: 10px;
  font-size: 0.85rem; color: #8B90C4;
}

/* ---------- Scroll to top ---------- */
.scroll-top-btn {
  position: fixed; right: 24px; bottom: 24px; z-index: 900;
  width: 48px; height: 48px; border-radius: 50%;
  background: var(--gradient-brand); color: #fff;
  display: flex; align-items: center; justify-content: center;
  font-size: 1.3rem; line-height: 1;
  box-shadow: var(--shadow-glow);
  opacity: 0; visibility: hidden; transform: translateY(10px);
  transition: all 0.3s ease;
}
.scroll-top-btn.show { opacity: 1; visibility: visible; transform: translateY(0); }

/* ---------- Page loader ---------- */
.page-loader {
  position: fixed; inset: 0; z-index: 3000;
  background: var(--color-indigo-deep);
  display: flex; align-items: center; justify-content: center;
  transition: opacity 0.5s ease, visibility 0.5s ease;
}
.page-loader.hidden { opacity: 0; visibility: hidden; }
.loader-eq { font-family: var(--font-mono); color: #fff; font-size: 1.4rem; display: flex; gap: 4px; }
.loader-eq span { animation: loaderPulse 1.2s ease-in-out infinite; }
.loader-eq span:nth-child(2) { animation-delay: 0.1s; }
.loader-eq span:nth-child(3) { animation-delay: 0.2s; }
.loader-eq span:nth-child(4) { animation-delay: 0.3s; }
.loader-eq span:nth-child(5) { animation-delay: 0.4s; }

/* ---------- Utility / inner page hero ---------- */
.page-hero {
  padding-top: calc(var(--header-h) + 4rem);
  padding-bottom: var(--space-xl);
  background: var(--gradient-hero);
  color: #fff;
  text-align: center;
}
.page-hero h1 { color: #fff; font-size: clamp(2rem, 4vw, 2.8rem); }
.page-hero p { color: #D4D6EE; max-width: 620px; margin: var(--space-sm) auto 0; }
.breadcrumbs { font-family: var(--font-mono); font-size: 0.8rem; color: #A9AEDD; margin-bottom: var(--space-sm); }
.breadcrumbs a { color: #C9D0FF; }

.legal-content { max-width: 780px; margin-inline: auto; }
.legal-content h2 { margin-top: var(--space-lg); margin-bottom: var(--space-sm); font-size: 1.35rem; }
.legal-content h3 { margin-top: var(--space-md); margin-bottom: 8px; font-size: 1.1rem; }
.legal-content p, .legal-content li { color: var(--color-ink-soft); margin-bottom: var(--space-sm); font-size: 0.98rem; }
.legal-content ul { padding-left: 1.2rem; list-style: disc; }
.legal-content .updated { font-family: var(--font-mono); font-size: 0.82rem; color: var(--color-ink-faint); }

/* Team / values cards used on About */
.value-card { text-align: center; }

/* Calculator tool widget (used on guides/solver demo) */
.tool-widget {
  background: var(--color-white); border: 1px solid var(--color-line); border-radius: var(--radius-lg);
  padding: var(--space-lg); box-shadow: var(--shadow-md);
}
.tool-widget .tool-row { display: flex; gap: 10px; margin-bottom: var(--space-sm); flex-wrap: wrap; }
.tool-widget input, .tool-widget select {
  padding: 12px 14px; border: 1.5px solid var(--color-line); border-radius: var(--radius-sm); flex: 1; min-width: 140px;
}
.tool-result {
  margin-top: var(--space-sm); padding: 16px 18px; border-radius: var(--radius-sm);
  background: var(--color-blue-soft); font-family: var(--font-mono); color: var(--color-indigo-deep);
  display: none;
}
.tool-result.show { display: block; }
.tool-result .steps { margin-top: 8px; font-size: 0.85rem; color: var(--color-ink-soft); }
.tool-error { color: #D8425A; }

/* ---------- Calculator Modal ---------- */
.calc-modal {
  position: fixed; inset: 0; z-index: 2000;
  display: flex; align-items: center; justify-content: center;
  padding: var(--space-md);
  opacity: 0; visibility: hidden;
  transition: opacity 0.3s ease, visibility 0.3s ease;
}
.calc-modal.open { opacity: 1; visibility: visible; }
.calc-modal-overlay {
  position: absolute; inset: 0;
  background: rgba(20, 17, 46, 0.55);
  backdrop-filter: blur(4px);
}
.calc-modal-box {
  position: relative;
  background: var(--color-white);
  border-radius: var(--radius-lg);
  padding: var(--space-lg);
  width: 100%; max-width: 440px;
  max-height: 86vh; overflow-y: auto;
  box-shadow: var(--shadow-lg);
  transform: translateY(16px) scale(0.97);
  transition: transform 0.3s ease;
}
.calc-modal.open .calc-modal-box { transform: translateY(0) scale(1); }
.calc-modal-close {
  position: absolute; top: 16px; right: 16px;
  width: 34px; height: 34px; border-radius: 50%;
  background: var(--color-bg-alt);
  display: flex; align-items: center; justify-content: center;
  font-size: 1.1rem; color: var(--color-ink-soft);
  transition: background 0.2s ease, color 0.2s ease;
}
.calc-modal-close:hover { background: var(--color-blue-soft); color: var(--color-blue); }
.calc-modal-box h3 { font-size: 1.25rem; margin-bottom: var(--space-md); padding-right: 30px; }

/* sitemap page */
.sitemap-list { columns: 3; column-gap: var(--space-lg); }
.sitemap-list .sitemap-block { break-inside: avoid; margin-bottom: var(--space-lg); }
.sitemap-list h4 { margin-bottom: 10px; }
.sitemap-list a { display: block; padding: 5px 0; color: var(--color-ink-soft); }
.sitemap-list a:hover { color: var(--color-blue); }