/* ============================================================
   style.css — Lucas Perez · Data & AI Consulting Website
   Modern, premium, responsive CSS (mobile-first)
   ============================================================ */

/* ──────────────────────────────────────────────────────────
   1. CSS CUSTOM PROPERTIES (Design Tokens)
   ────────────────────────────────────────────────────────── */
:root {
  /* Colour palette — light mode */
  --color-bg:            #f8f9fc;
  --color-surface:       #ffffff;
  --color-surface-alt:   #f0f4fb;
  --color-border:        #e2e8f4;
  --color-text:          #0f172a;
  --color-text-muted:    #64748b;
  --color-text-light:    #94a3b8;

  /* Brand accent — deep midnight blue + electric teal */
  --color-primary:       #1a3a6b;
  --color-primary-dark:  #112754;
  --color-primary-light: #2a5298;
  --color-accent:        #00c2a8;
  --color-accent-dark:   #00a38d;
  --color-accent-glow:   rgba(0, 194, 168, 0.18);

  /* Gradients */
  --grad-hero:   linear-gradient(135deg, #0f1f45 0%, #1a3a6b 50%, #0d2b55 100%);
  --grad-card:   linear-gradient(145deg, #ffffff 0%, #f0f4fb 100%);
  --grad-accent: linear-gradient(90deg, #00c2a8 0%, #0097d6 100%);

  /* Typography */
  --font-sans:   "Inter", "Segoe UI", system-ui, -apple-system, sans-serif;
  --font-mono:   "JetBrains Mono", "Fira Code", monospace;

  --fs-xs:   0.75rem;   /*  12px */
  --fs-sm:   0.875rem;  /*  14px */
  --fs-base: 1rem;      /*  16px */
  --fs-md:   1.125rem;  /*  18px */
  --fs-lg:   1.25rem;   /*  20px */
  --fs-xl:   1.5rem;    /*  24px */
  --fs-2xl:  1.875rem;  /*  30px */
  --fs-3xl:  2.25rem;   /*  36px */
  --fs-4xl:  3rem;      /*  48px */
  --fs-5xl:  3.75rem;   /*  60px */

  --fw-normal:   400;
  --fw-medium:   500;
  --fw-semibold: 600;
  --fw-bold:     700;
  --fw-extrabold:800;

  --lh-tight:  1.2;
  --lh-snug:   1.4;
  --lh-normal: 1.6;
  --lh-loose:  1.8;

  /* Spacing */
  --space-1:  0.25rem;
  --space-2:  0.5rem;
  --space-3:  0.75rem;
  --space-4:  1rem;
  --space-5:  1.25rem;
  --space-6:  1.5rem;
  --space-8:  2rem;
  --space-10: 2.5rem;
  --space-12: 3rem;
  --space-16: 4rem;
  --space-20: 5rem;
  --space-24: 6rem;
  --space-32: 8rem;

  /* Layout */
  --container-max: 1200px;
  --container-wide: 1400px;
  --section-py: var(--space-20);

  /* Borders & radius */
  --radius-sm:   0.375rem;
  --radius-md:   0.75rem;
  --radius-lg:   1rem;
  --radius-xl:   1.5rem;
  --radius-2xl:  2rem;
  --radius-full: 9999px;

  /* Shadows */
  --shadow-xs:  0 1px 3px rgba(15,31,69,0.06);
  --shadow-sm:  0 2px 8px rgba(15,31,69,0.08);
  --shadow-md:  0 4px 16px rgba(15,31,69,0.1);
  --shadow-lg:  0 8px 32px rgba(15,31,69,0.12);
  --shadow-xl:  0 16px 48px rgba(15,31,69,0.16);

  /* Transitions */
  --transition-fast:   150ms ease;
  --transition-base:   250ms ease;
  --transition-slow:   400ms ease;
  --transition-spring: 350ms cubic-bezier(0.34, 1.56, 0.64, 1);

  /* Header */
  --header-height: 72px;
}

/* Dark mode tokens */
[data-theme="dark"] {
  --color-bg:          #07111f;
  --color-surface:     #0f1e32;
  --color-surface-alt: #13253d;
  --color-border:      #1e3254;
  --color-text:        #e8edf5;
  --color-text-muted:  #8ba3c7;
  --color-text-light:  #5a7aa0;
  --grad-card:         linear-gradient(145deg, #0f1e32 0%, #13253d 100%);
  --shadow-xs:  0 1px 3px rgba(0,0,0,0.2);
  --shadow-sm:  0 2px 8px rgba(0,0,0,0.3);
  --shadow-md:  0 4px 16px rgba(0,0,0,0.35);
  --shadow-lg:  0 8px 32px rgba(0,0,0,0.4);
  --shadow-xl:  0 16px 48px rgba(0,0,0,0.5);
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-sans);
  font-size: var(--fs-base);
  line-height: var(--lh-normal);
  color: var(--color-text);
  background-color: var(--color-bg);
  transition: background-color var(--transition-slow), color var(--transition-slow);
  overflow-x: hidden;
}

img, svg {
  display: block;
  max-width: 100%;
}

a {
  color: inherit;
  text-decoration: none;
}

button {
  cursor: pointer;
  border: none;
  background: none;
  font-family: inherit;
}

ul, ol { list-style: none; }

::selection {
  background-color: var(--color-accent);
  color: #fff;
}

:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 3px;
}

/* ──────────────────────────────────────────────────────────
   3. TYPOGRAPHY HELPERS
   ────────────────────────────────────────────────────────── */
.text-xs     { font-size: var(--fs-xs); }
.text-sm     { font-size: var(--fs-sm); }
.text-base   { font-size: var(--fs-base); }
.text-md     { font-size: var(--fs-md); }
.text-lg     { font-size: var(--fs-lg); }
.text-xl     { font-size: var(--fs-xl); }
.text-2xl    { font-size: var(--fs-2xl); }
.text-3xl    { font-size: var(--fs-3xl); }
.text-4xl    { font-size: var(--fs-4xl); }
.text-muted  { color: var(--color-text-muted); }
.text-accent { color: var(--color-accent); }
.text-primary{ color: var(--color-primary); }
.fw-medium   { font-weight: var(--fw-medium); }
.fw-semibold { font-weight: var(--fw-semibold); }
.fw-bold     { font-weight: var(--fw-bold); }
.text-center { text-align: center; }

/* ──────────────────────────────────────────────────────────
   4. LAYOUT UTILITIES
   ────────────────────────────────────────────────────────── */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin-inline: auto;
  padding-inline: var(--space-6);
}

.container--wide {
  max-width: var(--container-wide);
}

section {
  padding-block: var(--section-py);
}

.section-header {
  text-align: center;
  margin-bottom: var(--space-16);
}

.section-label {
  display: inline-block;
  font-size: var(--fs-xs);
  font-weight: var(--fw-semibold);
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--color-accent);
  background: var(--color-accent-glow);
  padding: var(--space-1) var(--space-3);
  border-radius: var(--radius-full);
  margin-bottom: var(--space-4);
}

.section-title {
  font-size: clamp(var(--fs-2xl), 4vw, var(--fs-4xl));
  font-weight: var(--fw-bold);
  line-height: var(--lh-tight);
  color: var(--color-text);
  margin-bottom: var(--space-4);
}

.section-subtitle {
  font-size: var(--fs-md);
  color: var(--color-text-muted);
  max-width: 680px;
  margin-inline: auto;
  line-height: var(--lh-loose);
}

/* ──────────────────────────────────────────────────────────
   5. HEADER / NAVIGATION
   ────────────────────────────────────────────────────────── */
#header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  height: var(--header-height);
  display: flex;
  align-items: center;
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-border);
  transition: box-shadow var(--transition-base), background var(--transition-base);
}

[data-theme="dark"] #header {
  background: rgba(10, 20, 38, 0.92);
}

#header.scrolled {
  box-shadow: var(--shadow-md);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
}

/* Logo */
.logo {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  font-size: var(--fs-lg);
  font-weight: var(--fw-bold);
  color: var(--color-primary);
  letter-spacing: -0.02em;
}

[data-theme="dark"] .logo {
  color: #d6e4ff;
}

.logo-mark {
  width: 38px;
  height: 38px;
  background: var(--grad-accent);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-size: var(--fs-md);
  font-weight: var(--fw-extrabold);
  letter-spacing: -0.04em;
  flex-shrink: 0;
}

/* Main nav */
.nav-main {
  display: none;
}

.nav-main a {
  font-size: var(--fs-sm);
  font-weight: var(--fw-medium);
  color: var(--color-text-muted);
  padding: var(--space-2) var(--space-3);
  border-radius: var(--radius-sm);
  transition: color var(--transition-fast), background var(--transition-fast);
  white-space: nowrap;
}

.nav-main a:hover,
.nav-main a.active {
  color: var(--color-primary);
  background: var(--color-surface-alt);
}

[data-theme="dark"] .nav-main a:hover,
[data-theme="dark"] .nav-main a.active {
  color: var(--color-accent);
  background: rgba(0, 194, 168, 0.08);
}

/* Header controls */
.header-controls {
  display: flex;
  align-items: center;
  gap: var(--space-3);
}

/* Language selector */
.lang-selector {
  display: flex;
  align-items: center;
  gap: var(--space-1);
  background: var(--color-surface-alt);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-full);
  padding: var(--space-1);
}

.lang-btn {
  font-size: var(--fs-xs);
  font-weight: var(--fw-semibold);
  padding: 4px 8px;
  border-radius: var(--radius-full);
  color: var(--color-text-muted);
  transition: all var(--transition-fast);
  letter-spacing: 0.04em;
}

.lang-btn:hover {
  color: var(--color-text);
  background: var(--color-surface);
}

.lang-btn.active {
  background: var(--color-primary);
  color: #fff;
}

[data-theme="dark"] .lang-btn.active {
  background: var(--color-accent);
  color: #0f1e32;
}

/* Theme toggle */
.theme-toggle {
  width: 36px;
  height: 36px;
  border-radius: var(--radius-full);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-text-muted);
  background: var(--color-surface-alt);
  border: 1px solid var(--color-border);
  transition: all var(--transition-fast);
}

.theme-toggle:hover {
  color: var(--color-accent);
  border-color: var(--color-accent);
}

.theme-toggle .icon-sun  { display: none; }
.theme-toggle .icon-moon { display: block; }
[data-theme="dark"] .theme-toggle .icon-sun  { display: block; }
[data-theme="dark"] .theme-toggle .icon-moon { display: none; }

/* Hamburger */
.hamburger {
  width: 36px;
  height: 36px;
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  padding: 6px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--color-border);
  background: var(--color-surface-alt);
}

.hamburger span {
  display: block;
  height: 2px;
  background: var(--color-text);
  border-radius: var(--radius-full);
  transition: all var(--transition-base);
  transform-origin: center;
}

.hamburger.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.hamburger.open span:nth-child(2) { opacity: 0; transform: scaleX(0); }
.hamburger.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* Mobile menu */
.nav-mobile {
  position: fixed;
  top: var(--header-height);
  left: 0;
  right: 0;
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  box-shadow: var(--shadow-lg);
  transform: translateY(-110%);
  transition: transform var(--transition-slow);
  z-index: 999;
  padding: var(--space-4) var(--space-6) var(--space-6);
}

.nav-mobile.open {
  transform: translateY(0);
}

.nav-mobile a {
  display: block;
  font-size: var(--fs-md);
  font-weight: var(--fw-medium);
  color: var(--color-text);
  padding: var(--space-3) 0;
  border-bottom: 1px solid var(--color-border);
  transition: color var(--transition-fast);
}

.nav-mobile a:last-of-type { border-bottom: none; }

.nav-mobile a:hover { color: var(--color-accent); }

/* Nav mobile lang row */
.nav-mobile-langs {
  display: flex;
  gap: var(--space-2);
  margin-top: var(--space-4);
  padding-top: var(--space-4);
  border-top: 1px solid var(--color-border);
}

/* Desktop nav */
@media (min-width: 1024px) {
  .nav-main { display: flex; align-items: center; gap: var(--space-1); }
  .hamburger { display: none; }
}

/* ──────────────────────────────────────────────────────────
   6. HERO SECTION
   ────────────────────────────────────────────────────────── */
#hero {
  min-height: 100svh;
  display: flex;
  align-items: center;
  background: var(--grad-hero);
  position: relative;
  overflow: hidden;
  padding-top: var(--header-height);
}

/* Animated abstract background */
.hero-bg {
  position: absolute;
  inset: 0;
  pointer-events: none;
  overflow: hidden;
}

.hero-orb {
  position: absolute;
  border-radius: 50%;
  filter: blur(80px);
  opacity: 0.25;
  animation: orbFloat 8s ease-in-out infinite;
}

.hero-orb--1 {
  width: 600px; height: 600px;
  background: radial-gradient(circle, #00c2a8, transparent 70%);
  top: -200px; right: -100px;
  animation-delay: 0s;
}

.hero-orb--2 {
  width: 400px; height: 400px;
  background: radial-gradient(circle, #0097d6, transparent 70%);
  bottom: -100px; left: -50px;
  animation-delay: 3s;
}

.hero-orb--3 {
  width: 300px; height: 300px;
  background: radial-gradient(circle, #2a5298, transparent 70%);
  top: 50%; left: 40%;
  animation-delay: 5s;
}

@keyframes orbFloat {
  0%, 100% { transform: translate(0, 0) scale(1); }
  33%       { transform: translate(30px, -20px) scale(1.05); }
  66%       { transform: translate(-20px, 30px) scale(0.95); }
}

/* Hero grid lines decoration */
.hero-grid {
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(255,255,255,0.03) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255,255,255,0.03) 1px, transparent 1px);
  background-size: 60px 60px;
}

.hero-content {
  position: relative;
  z-index: 1;
  max-width: 800px;
}

.hero-badges {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
  margin-bottom: var(--space-8);
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  background: rgba(255,255,255,0.1);
  border: 1px solid rgba(255,255,255,0.15);
  color: rgba(255,255,255,0.85);
  font-size: var(--fs-xs);
  font-weight: var(--fw-medium);
  padding: var(--space-2) var(--space-3);
  border-radius: var(--radius-full);
  backdrop-filter: blur(8px);
}

.hero-badge::before {
  content: '';
  width: 6px; height: 6px;
  border-radius: 50%;
  background: var(--color-accent);
  flex-shrink: 0;
}

.hero-headline {
  font-size: clamp(var(--fs-3xl), 6vw, var(--fs-5xl));
  font-weight: var(--fw-extrabold);
  line-height: var(--lh-tight);
  color: #ffffff;
  margin-bottom: var(--space-6);
  letter-spacing: -0.02em;
}

.hero-headline .accent {
  background: var(--grad-accent);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-subtitle {
  font-size: clamp(var(--fs-base), 2vw, var(--fs-md));
  color: rgba(255,255,255,0.72);
  line-height: var(--lh-loose);
  max-width: 620px;
  margin-bottom: var(--space-10);
}

.hero-ctas {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-4);
}

/* ──────────────────────────────────────────────────────────
   7. BUTTONS
   ────────────────────────────────────────────────────────── */
.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  font-family: var(--font-sans);
  font-size: var(--fs-sm);
  font-weight: var(--fw-semibold);
  padding: 0.75rem 1.5rem;
  border-radius: var(--radius-full);
  border: 2px solid transparent;
  transition: all var(--transition-spring);
  letter-spacing: 0.01em;
  white-space: nowrap;
}

.btn-primary {
  background: var(--grad-accent);
  color: #fff;
  border-color: transparent;
  box-shadow: 0 4px 20px rgba(0,194,168,0.4);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 28px rgba(0,194,168,0.5);
}

.btn-outline {
  background: transparent;
  color: #fff;
  border-color: rgba(255,255,255,0.4);
}

.btn-outline:hover {
  background: rgba(255,255,255,0.1);
  border-color: rgba(255,255,255,0.7);
  transform: translateY(-2px);
}

.btn-ghost {
  background: transparent;
  color: var(--color-primary);
  border-color: var(--color-border);
}

.btn-ghost:hover {
  background: var(--color-surface-alt);
  border-color: var(--color-primary-light);
}

.btn-dark {
  background: var(--color-primary);
  color: #fff;
}

.btn-dark:hover {
  background: var(--color-primary-dark);
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

/* ──────────────────────────────────────────────────────────
   8. ABOUT SECTION
   ────────────────────────────────────────────────────────── */
#about {
  background: var(--color-surface);
}

.about-grid {
  display: grid;
  gap: var(--space-12);
  align-items: start;
}

/* Profile visual */
.about-visual {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-6);
}

.profile-image-wrap {
  position: relative;
  width: 260px;
  height: 260px;
  flex-shrink: 0;
}

.profile-image-wrap::before {
  content: '';
  position: absolute;
  inset: -8px;
  border-radius: var(--radius-2xl);
  background: var(--grad-accent);
  z-index: 0;
  opacity: 0.6;
  border-radius: 50%;
}

.profile-image {
  position: relative;
  z-index: 1;
  width: 100%;
  height: 100%;
  border-radius: 50%;
  object-fit: cover;
  background: var(--grad-hero);
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  border: 4px solid var(--color-surface);
}

.profile-placeholder {
  width: 100%;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--grad-hero);
  border-radius: 50%;
}

.profile-placeholder svg {
  width: 100px;
  height: 100px;
  opacity: 0.5;
}

/* Stats grid */
.stats-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-4);
  width: 100%;
  max-width: 320px;
}

.stat-card {
  background: var(--grad-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-5);
  text-align: center;
  transition: transform var(--transition-base), box-shadow var(--transition-base);
}

.stat-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
}

.stat-value {
  font-size: var(--fs-2xl);
  font-weight: var(--fw-extrabold);
  background: var(--grad-accent);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  line-height: 1;
  margin-bottom: var(--space-1);
}

.stat-label {
  font-size: var(--fs-xs);
  color: var(--color-text-muted);
  font-weight: var(--fw-medium);
  line-height: var(--lh-snug);
}

/* About text */
.about-text {
  display: flex;
  flex-direction: column;
  gap: var(--space-6);
}

.about-bio p {
  color: var(--color-text-muted);
  line-height: var(--lh-loose);
  margin-bottom: var(--space-4);
  font-size: var(--fs-md);
}

.about-bio p:last-child { margin-bottom: 0; }

/* Strengths */
.strengths-grid {
  display: grid;
  gap: var(--space-4);
}

.strength-card {
  display: flex;
  align-items: flex-start;
  gap: var(--space-4);
  padding: var(--space-5);
  background: var(--color-surface-alt);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  transition: transform var(--transition-base), border-color var(--transition-base);
}

.strength-card:hover {
  transform: translateX(6px);
  border-color: var(--color-accent);
}

.strength-icon {
  width: 44px;
  height: 44px;
  background: var(--grad-accent);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  color: #fff;
}

.strength-title {
  font-size: var(--fs-base);
  font-weight: var(--fw-semibold);
  color: var(--color-text);
  margin-bottom: var(--space-1);
}

.strength-desc {
  font-size: var(--fs-sm);
  color: var(--color-text-muted);
  line-height: var(--lh-snug);
}

@media (min-width: 768px) {
  .about-grid {
    grid-template-columns: 1fr 1.6fr;
  }
  .about-visual { align-items: flex-start; }
}

/* ──────────────────────────────────────────────────────────
   8b. CLIENTS SECTION
   ────────────────────────────────────────────────────────── */
#clients {
  background: var(--color-bg-alt);
  padding-block: var(--space-16);
}

.clients-grid {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-4) var(--space-5);
  justify-content: center;
  align-items: center;
  margin-top: var(--space-10);
}

.client-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-5) var(--space-6);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  min-width: 140px;
  max-width: 180px;
  flex: 1 1 140px;
  transition: transform var(--transition-base), box-shadow var(--transition-base), border-color var(--transition-base);
  cursor: default;
}

.client-item:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
  border-color: var(--color-primary);
}

.client-logo {
  width: 48px;
  height: 48px;
  color: var(--color-primary);
  flex-shrink: 0;
}

.client-logo svg {
  width: 100%;
  height: 100%;
}

.client-name {
  font-size: var(--fs-sm);
  font-weight: 600;
  color: var(--color-text);
  text-align: center;
  line-height: 1.3;
}

/* ──────────────────────────────────────────────────────────
   9. SERVICES SECTION
   ────────────────────────────────────────────────────────── */
#services {
  background: var(--color-bg);
}

.services-grid {
  display: grid;
  gap: var(--space-6);
  grid-template-columns: 1fr;
}

.service-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  overflow: hidden;
  transition: transform var(--transition-base), box-shadow var(--transition-base), border-color var(--transition-base);
  cursor: pointer;
}

.service-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-xl);
  border-color: var(--color-accent);
}

.service-card-header {
  padding: var(--space-6);
  display: flex;
  align-items: flex-start;
  gap: var(--space-4);
  border-bottom: 1px solid var(--color-border);
}

.service-icon {
  width: 52px;
  height: 52px;
  border-radius: var(--radius-lg);
  background: var(--grad-accent);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  flex-shrink: 0;
  font-size: var(--fs-xl);
}

.service-title {
  font-size: var(--fs-md);
  font-weight: var(--fw-semibold);
  color: var(--color-text);
  line-height: var(--lh-snug);
}

.service-card-body {
  padding: var(--space-6);
}

.service-desc {
  font-size: var(--fs-sm);
  color: var(--color-text-muted);
  line-height: var(--lh-loose);
  margin-bottom: var(--space-5);
}

/* Service expandable details */
.service-details {
  display: none;
  flex-direction: column;
  gap: var(--space-4);
  padding-top: var(--space-4);
  border-top: 1px dashed var(--color-border);
  animation: fadeSlide 0.3s ease;
}

.service-card.expanded .service-details {
  display: flex;
}

@keyframes fadeSlide {
  from { opacity: 0; transform: translateY(-8px); }
  to   { opacity: 1; transform: translateY(0); }
}

.service-detail-row {
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
}

.service-detail-label {
  font-size: var(--fs-xs);
  font-weight: var(--fw-semibold);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-accent);
}

.service-detail-value {
  font-size: var(--fs-sm);
  color: var(--color-text-muted);
  line-height: var(--lh-snug);
}

.service-expand-btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  font-size: var(--fs-sm);
  font-weight: var(--fw-semibold);
  color: var(--color-primary);
  transition: color var(--transition-fast);
  margin-top: var(--space-3);
}

[data-theme="dark"] .service-expand-btn { color: var(--color-accent); }

.service-expand-btn .chevron {
  transition: transform var(--transition-base);
}

.service-card.expanded .service-expand-btn .chevron {
  transform: rotate(180deg);
}

@media (min-width: 640px)  { .services-grid { grid-template-columns: 1fr 1fr; } }
@media (min-width: 1024px) { .services-grid { grid-template-columns: 1fr 1fr 1fr; } }

/* ──────────────────────────────────────────────────────────
   10. VALUE CHAIN SECTION
   ────────────────────────────────────────────────────────── */
#valuechain {
  background: var(--color-surface);
}

/* Chain graphic */
.vc-chain {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  margin-bottom: var(--space-12);
}

.vc-step {
  display: flex;
  align-items: center;
  gap: var(--space-4);
  background: var(--color-surface-alt);
  border: 2px solid var(--color-border);
  border-radius: var(--radius-xl);
  padding: var(--space-5) var(--space-6);
  cursor: pointer;
  transition: all var(--transition-base);
  user-select: none;
}

.vc-step:hover,
.vc-step.active {
  border-color: var(--color-accent);
  background: var(--color-surface);
  box-shadow: var(--shadow-md), 0 0 0 3px var(--color-accent-glow);
}

.vc-step.active .vc-step-label {
  color: var(--color-accent);
}

.vc-step-number {
  width: 40px;
  height: 40px;
  background: var(--color-primary);
  color: #fff;
  font-size: var(--fs-sm);
  font-weight: var(--fw-bold);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  transition: background var(--transition-base);
}

.vc-step.active .vc-step-number {
  background: var(--color-accent);
}

.vc-step-label {
  font-size: var(--fs-md);
  font-weight: var(--fw-semibold);
  color: var(--color-text);
  transition: color var(--transition-fast);
}

.vc-step-tagline {
  font-size: var(--fs-sm);
  color: var(--color-text-muted);
}

.vc-step-arrow {
  margin-left: auto;
  color: var(--color-text-light);
  transition: transform var(--transition-base), color var(--transition-base);
}

.vc-step.active .vc-step-arrow {
  color: var(--color-accent);
  transform: rotate(90deg);
}

/* Value chain detail panel */
.vc-detail {
  background: var(--color-surface-alt);
  border: 2px solid var(--color-accent);
  border-radius: var(--radius-xl);
  padding: var(--space-8);
  animation: fadeSlide 0.35s ease;
  display: none;
}

.vc-detail.visible { display: block; }

.vc-detail-title {
  font-size: var(--fs-xl);
  font-weight: var(--fw-bold);
  color: var(--color-text);
  margin-bottom: var(--space-6);
  display: flex;
  align-items: center;
  gap: var(--space-3);
}

.vc-detail-title-badge {
  background: var(--grad-accent);
  color: #fff;
  font-size: var(--fs-xs);
  padding: var(--space-1) var(--space-3);
  border-radius: var(--radius-full);
  font-weight: var(--fw-semibold);
}

.vc-detail-grid {
  display: grid;
  gap: var(--space-5);
}

.vc-detail-item-label {
  font-size: var(--fs-xs);
  font-weight: var(--fw-semibold);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--color-accent);
  margin-bottom: var(--space-2);
}

.vc-detail-item-value {
  font-size: var(--fs-sm);
  color: var(--color-text-muted);
  line-height: var(--lh-loose);
}

.vc-hint {
  text-align: center;
  font-size: var(--fs-sm);
  color: var(--color-text-light);
  margin-bottom: var(--space-6);
  font-style: italic;
}

@media (min-width: 768px) {
  .vc-chain {
    flex-direction: row;
    flex-wrap: nowrap;
    overflow-x: auto;
    gap: 0;
    padding-bottom: var(--space-4);
  }

  .vc-step {
    flex: 1;
    min-width: 130px;
    flex-direction: column;
    align-items: center;
    text-align: center;
    padding: var(--space-5) var(--space-3);
    border-radius: var(--radius-md);
    position: relative;
  }

  .vc-step:not(:last-child)::after {
    content: '→';
    position: absolute;
    right: -16px;
    top: 50%;
    transform: translateY(-50%);
    color: var(--color-text-light);
    font-size: var(--fs-lg);
    z-index: 2;
  }

  .vc-step:not(:first-child) { margin-left: var(--space-4); }

  .vc-step-label { font-size: var(--fs-sm); }
  .vc-step-tagline { display: none; }
  .vc-step-arrow { display: none; }

  .vc-detail-grid {
    grid-template-columns: 1fr 1fr;
  }
}

@media (min-width: 1024px) {
  .vc-detail-grid {
    grid-template-columns: 1fr 1fr 1fr;
  }
}

/* ──────────────────────────────────────────────────────────
   11. EXPERTISE SECTION
   ────────────────────────────────────────────────────────── */
#expertise {
  background: var(--color-bg);
}

.expertise-domains {
  display: grid;
  gap: var(--space-5);
  margin-bottom: var(--space-20);
}

.expertise-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  padding: var(--space-6);
  transition: transform var(--transition-base), box-shadow var(--transition-base), border-color var(--transition-base);
  position: relative;
  overflow: hidden;
}

.expertise-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: var(--grad-accent);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--transition-base);
}

.expertise-card:hover::before { transform: scaleX(1); }

.expertise-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
  border-color: var(--color-primary-light);
}

.expertise-icon {
  width: 48px;
  height: 48px;
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-light) 100%);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  margin-bottom: var(--space-4);
  font-size: var(--fs-xl);
}

.expertise-title {
  font-size: var(--fs-md);
  font-weight: var(--fw-semibold);
  color: var(--color-text);
  margin-bottom: var(--space-3);
}

.expertise-desc {
  font-size: var(--fs-sm);
  color: var(--color-text-muted);
  line-height: var(--lh-loose);
}

@media (min-width: 640px)  { .expertise-domains { grid-template-columns: 1fr 1fr; } }
@media (min-width: 1024px) { .expertise-domains { grid-template-columns: 1fr 1fr 1fr 1fr; } }

/* Tech ecosystem */
.tech-ecosystem {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-2xl);
  padding: var(--space-10);
}

.tech-header {
  margin-bottom: var(--space-10);
}

.tech-categories-grid {
  display: grid;
  gap: var(--space-6);
}

.tech-category {
  background: var(--color-surface-alt);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-5);
  transition: border-color var(--transition-base);
}

.tech-category:hover { border-color: var(--color-accent); }

.tech-category-name {
  font-size: var(--fs-xs);
  font-weight: var(--fw-bold);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--color-primary);
  margin-bottom: var(--space-4);
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

[data-theme="dark"] .tech-category-name { color: var(--color-accent); }

.tech-category-name::before {
  content: '';
  width: 16px;
  height: 3px;
  background: var(--grad-accent);
  border-radius: var(--radius-full);
}

.tech-tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
}

.tech-tag {
  font-size: var(--fs-xs);
  font-weight: var(--fw-medium);
  color: var(--color-text-muted);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  padding: 4px 10px;
  border-radius: var(--radius-full);
  transition: all var(--transition-fast);
}

.tech-tag:hover {
  color: var(--color-accent);
  border-color: var(--color-accent);
  background: var(--color-accent-glow);
}

@media (min-width: 640px)  { .tech-categories-grid { grid-template-columns: 1fr 1fr; } }
@media (min-width: 1024px) { .tech-categories-grid { grid-template-columns: 1fr 1fr 1fr; } }

/* ──────────────────────────────────────────────────────────
   12. WHY SECTION
   ────────────────────────────────────────────────────────── */
#why {
  background: var(--color-surface);
  position: relative;
  overflow: hidden;
}

#why::before {
  content: '';
  position: absolute;
  top: -50%;
  right: -20%;
  width: 700px;
  height: 700px;
  background: radial-gradient(circle, var(--color-accent-glow) 0%, transparent 70%);
  pointer-events: none;
}

.why-grid {
  display: grid;
  gap: var(--space-6);
}

.why-card {
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
  padding: var(--space-7);
  background: var(--grad-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  transition: transform var(--transition-base), box-shadow var(--transition-base);
}

.why-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-xl);
}

.why-icon {
  width: 56px;
  height: 56px;
  border-radius: var(--radius-lg);
  background: var(--grad-accent);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-size: var(--fs-2xl);
}

.why-title {
  font-size: var(--fs-md);
  font-weight: var(--fw-semibold);
  color: var(--color-text);
}

.why-desc {
  font-size: var(--fs-sm);
  color: var(--color-text-muted);
  line-height: var(--lh-loose);
  flex: 1;
}

@media (min-width: 640px)  { .why-grid { grid-template-columns: 1fr 1fr; } }
@media (min-width: 1024px) { .why-grid { grid-template-columns: 1fr 1fr 1fr; } }

/* ──────────────────────────────────────────────────────────
   13. CONTACT CTA SECTION
   ────────────────────────────────────────────────────────── */
#contact-cta {
  background: var(--grad-hero);
  position: relative;
  overflow: hidden;
}

#contact-cta::before {
  content: '';
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(255,255,255,0.03) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255,255,255,0.03) 1px, transparent 1px);
  background-size: 60px 60px;
}

.cta-content {
  position: relative;
  z-index: 1;
  text-align: center;
}

.cta-title {
  font-size: clamp(var(--fs-2xl), 4vw, var(--fs-4xl));
  font-weight: var(--fw-bold);
  color: #fff;
  margin-bottom: var(--space-4);
  letter-spacing: -0.02em;
  line-height: var(--lh-tight);
}

.cta-subtitle {
  font-size: var(--fs-md);
  color: rgba(255,255,255,0.7);
  max-width: 620px;
  margin: 0 auto var(--space-10);
  line-height: var(--lh-loose);
}

.cta-items {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: var(--space-3);
  margin-bottom: var(--space-10);
}

.cta-item {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  background: rgba(255,255,255,0.08);
  border: 1px solid rgba(255,255,255,0.15);
  color: rgba(255,255,255,0.85);
  font-size: var(--fs-sm);
  font-weight: var(--fw-medium);
  padding: var(--space-2) var(--space-4);
  border-radius: var(--radius-full);
  transition: all var(--transition-fast);
}

.cta-item::before {
  content: '✓';
  color: var(--color-accent);
  font-weight: var(--fw-bold);
}

.cta-item:hover {
  background: rgba(255,255,255,0.14);
  border-color: rgba(255,255,255,0.3);
}

/* ──────────────────────────────────────────────────────────
   14. CONTACT FORM SECTION
   ────────────────────────────────────────────────────────── */
#contact {
  background: var(--color-bg);
}

.contact-grid {
  display: grid;
  gap: var(--space-12);
}

/* Contact info side */
.contact-info {
  display: flex;
  flex-direction: column;
  gap: var(--space-6);
}

.contact-info-title {
  font-size: var(--fs-xl);
  font-weight: var(--fw-bold);
  color: var(--color-text);
  margin-bottom: var(--space-2);
}

.contact-info-subtitle {
  font-size: var(--fs-base);
  color: var(--color-text-muted);
  line-height: var(--lh-loose);
  margin-bottom: var(--space-6);
}

.contact-links {
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
}

.contact-link-item {
  display: flex;
  align-items: center;
  gap: var(--space-4);
  padding: var(--space-4);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
  color: var(--color-text);
}

.contact-link-item:hover {
  border-color: var(--color-accent);
  box-shadow: var(--shadow-sm);
}

.contact-link-icon {
  width: 40px;
  height: 40px;
  background: var(--color-surface-alt);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-primary);
  flex-shrink: 0;
}

[data-theme="dark"] .contact-link-icon { color: var(--color-accent); }

.contact-link-label {
  font-size: var(--fs-xs);
  color: var(--color-text-muted);
  font-weight: var(--fw-medium);
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.contact-link-value {
  font-size: var(--fs-sm);
  font-weight: var(--fw-semibold);
  color: var(--color-text);
}

/* Contact form */
.contact-form-wrap {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-2xl);
  padding: var(--space-8);
  box-shadow: var(--shadow-lg);
}

.form-row {
  display: grid;
  gap: var(--space-4);
  margin-bottom: var(--space-4);
}

.form-group {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

.form-label {
  font-size: var(--fs-sm);
  font-weight: var(--fw-semibold);
  color: var(--color-text);
}

.form-label .required {
  color: #ef4444;
  margin-left: 2px;
}

.form-input,
.form-textarea,
.form-select {
  width: 100%;
  font-family: var(--font-sans);
  font-size: var(--fs-sm);
  color: var(--color-text);
  background: var(--color-surface-alt);
  border: 1.5px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 0.75rem 1rem;
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
  outline: none;
}

.form-input:focus,
.form-textarea:focus,
.form-select:focus {
  border-color: var(--color-accent);
  box-shadow: 0 0 0 3px var(--color-accent-glow);
}

.form-input.error,
.form-textarea.error {
  border-color: #ef4444;
  box-shadow: 0 0 0 3px rgba(239,68,68,0.1);
}

.form-textarea {
  min-height: 150px;
  resize: vertical;
  line-height: var(--lh-loose);
}

.form-error-msg {
  font-size: var(--fs-xs);
  color: #ef4444;
  display: none;
}

.form-error-msg.visible { display: block; }

.form-success-banner {
  display: none;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-4);
  background: rgba(0, 194, 168, 0.1);
  border: 1px solid var(--color-accent);
  border-radius: var(--radius-lg);
  color: var(--color-accent);
  font-size: var(--fs-sm);
  font-weight: var(--fw-semibold);
  margin-bottom: var(--space-4);
}

.form-success-banner.visible { display: flex; }

@media (min-width: 576px) {
  .form-row { grid-template-columns: 1fr 1fr; }
}

@media (min-width: 1024px) {
  .contact-grid { grid-template-columns: 1fr 1.4fr; }
}

/* ──────────────────────────────────────────────────────────
   15. FOOTER
   ────────────────────────────────────────────────────────── */
#footer {
  background: var(--color-primary-dark);
  color: rgba(255,255,255,0.7);
  padding-block: var(--space-16) var(--space-8);
}

.footer-grid {
  display: grid;
  gap: var(--space-10);
  margin-bottom: var(--space-10);
}

.footer-brand {
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
}

.footer-logo {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  color: #fff;
  font-size: var(--fs-lg);
  font-weight: var(--fw-bold);
}

.footer-tagline {
  font-size: var(--fs-sm);
  line-height: var(--lh-loose);
  color: rgba(255,255,255,0.55);
  max-width: 280px;
}

.footer-col-title {
  font-size: var(--fs-sm);
  font-weight: var(--fw-semibold);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: rgba(255,255,255,0.5);
  margin-bottom: var(--space-4);
}

.footer-links {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.footer-links a {
  font-size: var(--fs-sm);
  color: rgba(255,255,255,0.65);
  transition: color var(--transition-fast);
}

.footer-links a:hover { color: var(--color-accent); }

.footer-bottom {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  padding-top: var(--space-6);
  border-top: 1px solid rgba(255,255,255,0.1);
}

.footer-copyright {
  font-size: var(--fs-xs);
  color: rgba(255,255,255,0.4);
}

.footer-legal {
  display: flex;
  gap: var(--space-4);
}

.footer-legal a {
  font-size: var(--fs-xs);
  color: rgba(255,255,255,0.4);
  transition: color var(--transition-fast);
}

.footer-legal a:hover { color: var(--color-accent); }

@media (min-width: 640px) {
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .footer-bottom { flex-direction: row; justify-content: space-between; align-items: center; }
}

@media (min-width: 1024px) {
  .footer-grid { grid-template-columns: 2fr 1fr 1fr; }
}

/* ──────────────────────────────────────────────────────────
   16. BACK TO TOP BUTTON
   ────────────────────────────────────────────────────────── */
.back-to-top {
  position: fixed;
  bottom: var(--space-6);
  right: var(--space-6);
  width: 44px;
  height: 44px;
  background: var(--color-primary);
  color: #fff;
  border-radius: var(--radius-full);
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: var(--shadow-lg);
  opacity: 0;
  transform: translateY(20px);
  pointer-events: none;
  transition: all var(--transition-base);
  z-index: 90;
}

.back-to-top.visible {
  opacity: 1;
  transform: translateY(0);
  pointer-events: all;
}

.back-to-top:hover {
  background: var(--color-accent);
  transform: translateY(-4px);
}

/* ──────────────────────────────────────────────────────────
   17. SVG ICON SYSTEM (inline sprite helpers)
   ────────────────────────────────────────────────────────── */
.icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

/* ──────────────────────────────────────────────────────────
   18. ANIMATIONS & SCROLL REVEAL
   ────────────────────────────────────────────────────────── */
.reveal {
  opacity: 0;
  transform: translateY(28px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

.reveal-left {
  opacity: 0;
  transform: translateX(-28px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.reveal-left.visible {
  opacity: 1;
  transform: translateX(0);
}

.reveal-right {
  opacity: 0;
  transform: translateX(28px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.reveal-right.visible {
  opacity: 1;
  transform: translateX(0);
}

/* Stagger children */
.stagger-children > * {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.55s ease, transform 0.55s ease;
}

.stagger-children.visible > *:nth-child(1) { transition-delay: 0ms; }
.stagger-children.visible > *:nth-child(2) { transition-delay: 80ms; }
.stagger-children.visible > *:nth-child(3) { transition-delay: 160ms; }
.stagger-children.visible > *:nth-child(4) { transition-delay: 240ms; }
.stagger-children.visible > *:nth-child(5) { transition-delay: 320ms; }
.stagger-children.visible > *:nth-child(6) { transition-delay: 400ms; }
.stagger-children.visible > *:nth-child(7) { transition-delay: 480ms; }
.stagger-children.visible > *:nth-child(8) { transition-delay: 560ms; }
.stagger-children.visible > *:nth-child(9) { transition-delay: 640ms; }
.stagger-children.visible > *:nth-child(10){ transition-delay: 720ms; }
.stagger-children.visible > * { opacity: 1; transform: translateY(0); }

/* ──────────────────────────────────────────────────────────
   19. UTILITY CLASSES
   ────────────────────────────────────────────────────────── */
.sr-only {
  position: absolute;
  width: 1px; height: 1px;
  padding: 0; margin: -1px;
  overflow: hidden;
  clip: rect(0,0,0,0);
  white-space: nowrap;
  border: 0;
}

.hidden { display: none !important; }

/* ──────────────────────────────────────────────────────────
   20. MEDIA QUERY — LARGE DESKTOP REFINEMENTS
   ────────────────────────────────────────────────────────── */
@media (min-width: 1280px) {
  .hero-content { max-width: 900px; }
  :root { --section-py: 6rem; }
}

/* ──────────────────────────────────────────────────────────
   21. PRINT STYLES
   ────────────────────────────────────────────────────────── */
@media print {
  #header, .back-to-top, .hamburger, .nav-mobile { display: none !important; }
  body { background: #fff; color: #000; }
  section { padding-block: 2rem; }
}