/* ==========================================================================
   VoltMind AI Website - Professional B2B Design
   NO GRADIENTS | Clean | Trustworthy | Modern
   ========================================================================== */

/* ==========================================================================
   CSS VARIABLES - Color Scheme & Typography
   ========================================================================== */
:root {
  /* Colors - NO GRADIENTS */
  --color-primary: #0F172A;      /* Deep Navy Blue */
  --color-secondary: #FFFFFF;    /* Clean White */
  --color-accent: #2563EB;       /* Electric Blue - CTAs only */
  --color-neutral: #64748B;      /* Slate Gray */
  --color-success: #059669;      /* Professional Green */
  --color-background: #F8FAFC;   /* Light Gray */
  --color-border: #E2E8F0;       /* Border color */
  --color-text-primary: #0F172A;
  --color-text-secondary: #64748B;

  /* Typography */
  --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-size-base: 16px;
  --font-weight-regular: 400;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;
  --font-weight-bold: 700;

  /* Spacing */
  --spacing-xs: 8px;
  --spacing-sm: 16px;
  --spacing-md: 24px;
  --spacing-lg: 32px;
  --spacing-xl: 48px;
  --spacing-2xl: 64px;
  --spacing-3xl: 96px;

  /* Shadows */
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1);

  /* Border Radius */
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;

  /* Transitions */
  --transition-base: all 0.2s ease;
}

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

html {
  font-size: var(--font-size-base);
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-family);
  font-weight: var(--font-weight-regular);
  line-height: 1.6;
  color: var(--color-text-primary);
  background-color: var(--color-secondary);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

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

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

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

/* ==========================================================================
   TYPOGRAPHY
   ========================================================================== */
h1, h2, h3, h4, h5, h6 {
  font-weight: var(--font-weight-bold);
  line-height: 1.2;
  color: var(--color-primary);
  margin-bottom: var(--spacing-md);
}

h1 {
  font-size: 3.5rem;
  letter-spacing: -0.02em;
}

h2 {
  font-size: 2.5rem;
  letter-spacing: -0.01em;
}

h3 {
  font-size: 2rem;
}

h4 {
  font-size: 1.5rem;
}

h5 {
  font-size: 1.25rem;
}

h6 {
  font-size: 1rem;
}

p {
  margin-bottom: var(--spacing-sm);
  color: var(--color-text-secondary);
  font-size: 1.125rem;
  line-height: 1.7;
}

.text-large {
  font-size: 1.25rem;
}

.text-small {
  font-size: 0.875rem;
}

.text-primary {
  color: var(--color-primary);
}

.text-accent {
  color: var(--color-accent);
}

.text-center {
  text-align: center;
}

/* ==========================================================================
   LAYOUT & CONTAINERS
   ========================================================================== */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--spacing-lg);
}

.container-wide {
  max-width: 1400px;
  margin: 0 auto;
  padding: 0 var(--spacing-lg);
}

.section {
  padding: var(--spacing-3xl) 0;
}

.section-sm {
  padding: var(--spacing-2xl) 0;
}

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

/* ==========================================================================
   HEADER & NAVIGATION
   ========================================================================== */
.header {
  position: sticky;
  top: 0;
  background-color: var(--color-secondary);
  border-bottom: 1px solid var(--color-border);
  z-index: 1000;
  box-shadow: var(--shadow-sm);
}

.header__container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--spacing-sm) var(--spacing-lg);
  max-width: 1400px;
  margin: 0 auto;
}

.header__logo {
  font-size: 1.5rem;
  font-weight: var(--font-weight-bold);
  color: var(--color-primary);
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
}

.header__nav {
  display: flex;
  gap: var(--spacing-lg);
  align-items: center;
}

.header__nav-list {
  display: flex;
  gap: var(--spacing-lg);
  list-style: none;
  align-items: center;
}

.header__nav-link {
  color: var(--color-text-primary);
  font-weight: var(--font-weight-medium);
  font-size: 0.9375rem;
  transition: var(--transition-base);
  padding: var(--spacing-xs) 0;
}

.header__nav-link:hover {
  color: var(--color-accent);
}

.header__nav-link.active {
  color: var(--color-accent);
}

.header__mobile-toggle {
  display: none;
  flex-direction: column;
  gap: 4px;
  padding: var(--spacing-xs);
}

.header__mobile-toggle span {
  width: 24px;
  height: 2px;
  background-color: var(--color-primary);
  transition: var(--transition-base);
}

/* ==========================================================================
   BUTTONS - NO GRADIENTS
   ========================================================================== */
.btn {
  display: inline-block;
  padding: 14px 32px;
  font-weight: var(--font-weight-semibold);
  font-size: 1rem;
  text-align: center;
  border-radius: var(--radius-md);
  transition: var(--transition-base);
  cursor: pointer;
  border: 2px solid transparent;
  line-height: 1.5;
}

.btn-primary {
  background-color: var(--color-accent);
  color: var(--color-secondary);
  box-shadow: var(--shadow-md);
}

.btn-primary:hover {
  background-color: #1D4ED8;
  box-shadow: var(--shadow-lg);
  transform: translateY(-1px);
}

.btn-secondary {
  background-color: var(--color-secondary);
  color: var(--color-accent);
  border: 2px solid var(--color-accent);
}

.btn-secondary:hover {
  background-color: var(--color-accent);
  color: var(--color-secondary);
}

.btn-large {
  padding: 18px 40px;
  font-size: 1.125rem;
}

.btn-small {
  padding: 10px 24px;
  font-size: 0.875rem;
}

.btn-block {
  display: block;
  width: 100%;
}

/* ==========================================================================
   CARDS
   ========================================================================== */
.card {
  background-color: var(--color-secondary);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--spacing-lg);
  transition: var(--transition-base);
}

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

.card__icon {
  width: 48px;
  height: 48px;
  color: var(--color-accent);
  margin-bottom: var(--spacing-md);
}

.card__title {
  font-size: 1.5rem;
  font-weight: var(--font-weight-semibold);
  color: var(--color-primary);
  margin-bottom: var(--spacing-sm);
}

.card__description {
  color: var(--color-text-secondary);
  margin-bottom: var(--spacing-md);
  line-height: 1.6;
}

.card__list {
  list-style: none;
  margin-bottom: var(--spacing-md);
}

.card__list-item {
  color: var(--color-text-secondary);
  padding: var(--spacing-xs) 0;
  display: flex;
  align-items: flex-start;
  gap: var(--spacing-xs);
}

.card__list-item::before {
  content: "✓";
  color: var(--color-success);
  font-weight: var(--font-weight-bold);
  flex-shrink: 0;
}

.card__link {
  color: var(--color-accent);
  font-weight: var(--font-weight-semibold);
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-xs);
  transition: var(--transition-base);
}

.card__link:hover {
  gap: 12px;
}

/* ==========================================================================
   FORMS
   ========================================================================== */
.form {
  max-width: 600px;
}

.form__group {
  margin-bottom: var(--spacing-md);
}

.form__label {
  display: block;
  font-weight: var(--font-weight-medium);
  color: var(--color-primary);
  margin-bottom: var(--spacing-xs);
  font-size: 0.9375rem;
}

.form__input,
.form__textarea,
.form__select {
  width: 100%;
  padding: 14px 16px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  font-family: inherit;
  font-size: 1rem;
  color: var(--color-text-primary);
  background-color: var(--color-secondary);
  transition: var(--transition-base);
}

.form__input:focus,
.form__textarea:focus,
.form__select:focus {
  outline: none;
  border-color: var(--color-accent);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.form__textarea {
  min-height: 150px;
  resize: vertical;
}

.form__checkbox-group {
  display: flex;
  align-items: flex-start;
  gap: var(--spacing-xs);
}

.form__checkbox {
  margin-top: 4px;
  cursor: pointer;
}

.form__checkbox-label {
  font-size: 0.875rem;
  color: var(--color-text-secondary);
  cursor: pointer;
}

.form__error {
  color: #DC2626;
  font-size: 0.875rem;
  margin-top: var(--spacing-xs);
}

.form__success {
  color: var(--color-success);
  font-size: 0.875rem;
  margin-top: var(--spacing-xs);
}

/* ==========================================================================
   GRID LAYOUTS
   ========================================================================== */
.grid {
  display: grid;
  gap: var(--spacing-lg);
}

.grid-2 {
  grid-template-columns: repeat(2, 1fr);
}

.grid-3 {
  grid-template-columns: repeat(3, 1fr);
}

.grid-4 {
  grid-template-columns: repeat(4, 1fr);
}

/* ==========================================================================
   HERO SECTION
   ========================================================================== */
.hero {
  background-color: var(--color-secondary);
  padding: var(--spacing-3xl) 0;
  border-bottom: 1px solid var(--color-border);
}

.hero__container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--spacing-lg);
  text-align: center;
}

.hero__title {
  font-size: 3.5rem;
  font-weight: var(--font-weight-bold);
  color: var(--color-primary);
  margin-bottom: var(--spacing-md);
  line-height: 1.1;
}

.hero__subtitle {
  font-size: 1.25rem;
  color: var(--color-text-secondary);
  margin-bottom: var(--spacing-xl);
  max-width: 700px;
  margin-left: auto;
  margin-right: auto;
  line-height: 1.6;
}

.hero__cta {
  display: flex;
  gap: var(--spacing-md);
  justify-content: center;
  flex-wrap: wrap;
  margin-bottom: var(--spacing-xl);
}

.hero__trust {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-xs);
  color: var(--color-text-secondary);
  font-size: 0.9375rem;
}

.hero__trust-icon {
  color: var(--color-success);
}

/* ==========================================================================
   STATS SECTION
   ========================================================================== */
.stats {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: var(--spacing-lg);
}

.stat-card {
  text-align: center;
  padding: var(--spacing-lg);
  background-color: var(--color-secondary);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
}

.stat-card__number {
  font-size: 3rem;
  font-weight: var(--font-weight-bold);
  color: var(--color-accent);
  margin-bottom: var(--spacing-xs);
  line-height: 1;
}

.stat-card__label {
  font-size: 1rem;
  color: var(--color-text-secondary);
  font-weight: var(--font-weight-medium);
}

/* ==========================================================================
   PROCESS/TIMELINE
   ========================================================================== */
.process {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: var(--spacing-xl);
}

.process-step {
  text-align: center;
  position: relative;
}

.process-step__number {
  width: 64px;
  height: 64px;
  background-color: var(--color-accent);
  color: var(--color-secondary);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  font-weight: var(--font-weight-bold);
  margin: 0 auto var(--spacing-md);
}

.process-step__title {
  font-size: 1.25rem;
  font-weight: var(--font-weight-semibold);
  color: var(--color-primary);
  margin-bottom: var(--spacing-sm);
}

.process-step__description {
  color: var(--color-text-secondary);
  line-height: 1.6;
}

/* ==========================================================================
   TESTIMONIALS
   ========================================================================== */
.testimonial {
  background-color: var(--color-secondary);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--spacing-lg);
}

.testimonial__quote {
  font-size: 1.125rem;
  color: var(--color-text-primary);
  margin-bottom: var(--spacing-md);
  line-height: 1.7;
  font-style: italic;
}

.testimonial__author {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
}

.testimonial__author-image {
  width: 56px;
  height: 56px;
  border-radius: 50%;
  background-color: var(--color-background);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: var(--font-weight-bold);
  color: var(--color-accent);
  font-size: 1.25rem;
}

.testimonial__author-info {
  flex: 1;
}

.testimonial__author-name {
  font-weight: var(--font-weight-semibold);
  color: var(--color-primary);
  margin-bottom: 2px;
}

.testimonial__author-title {
  font-size: 0.875rem;
  color: var(--color-text-secondary);
}

/* ==========================================================================
   FOOTER
   ========================================================================== */
.footer {
  background-color: var(--color-primary);
  color: var(--color-secondary);
  padding: var(--spacing-2xl) 0 var(--spacing-lg);
}

.footer__container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--spacing-lg);
}

.footer__main {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: var(--spacing-xl);
  margin-bottom: var(--spacing-xl);
  padding-bottom: var(--spacing-xl);
  border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.footer__brand {
  max-width: 350px;
}

.footer__logo {
  font-size: 1.5rem;
  font-weight: var(--font-weight-bold);
  margin-bottom: var(--spacing-md);
}

.footer__description {
  color: rgba(255, 255, 255, 0.8);
  margin-bottom: var(--spacing-md);
  line-height: 1.6;
}

.footer__section-title {
  font-size: 1rem;
  font-weight: var(--font-weight-semibold);
  margin-bottom: var(--spacing-md);
  color: var(--color-secondary);
}

.footer__links {
  list-style: none;
}

.footer__link {
  color: rgba(255, 255, 255, 0.8);
  margin-bottom: var(--spacing-sm);
  transition: var(--transition-base);
  display: block;
}

.footer__link:hover {
  color: var(--color-secondary);
}

.footer__newsletter {
  display: flex;
  gap: var(--spacing-xs);
  margin-top: var(--spacing-md);
}

.footer__newsletter-input {
  flex: 1;
  padding: 12px 16px;
  border: 1px solid rgba(255, 255, 255, 0.2);
  border-radius: var(--radius-md);
  background-color: rgba(255, 255, 255, 0.1);
  color: var(--color-secondary);
  font-size: 0.9375rem;
}

.footer__newsletter-input::placeholder {
  color: rgba(255, 255, 255, 0.6);
}

.footer__newsletter-input:focus {
  outline: none;
  border-color: var(--color-accent);
  background-color: rgba(255, 255, 255, 0.15);
}

.footer__bottom {
  display: flex;
  justify-content: space-between;
  align-items: center;
  color: rgba(255, 255, 255, 0.6);
  font-size: 0.875rem;
}

.footer__social {
  display: flex;
  gap: var(--spacing-md);
}

.footer__social-link {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background-color: rgba(255, 255, 255, 0.1);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: var(--transition-base);
}

.footer__social-link:hover {
  background-color: var(--color-accent);
}

/* ==========================================================================
   UTILITY CLASSES
   ========================================================================== */
.mt-xs { margin-top: var(--spacing-xs); }
.mt-sm { margin-top: var(--spacing-sm); }
.mt-md { margin-top: var(--spacing-md); }
.mt-lg { margin-top: var(--spacing-lg); }
.mt-xl { margin-top: var(--spacing-xl); }
.mt-2xl { margin-top: var(--spacing-2xl); }

.mb-xs { margin-bottom: var(--spacing-xs); }
.mb-sm { margin-bottom: var(--spacing-sm); }
.mb-md { margin-bottom: var(--spacing-md); }
.mb-lg { margin-bottom: var(--spacing-lg); }
.mb-xl { margin-bottom: var(--spacing-xl); }
.mb-2xl { margin-bottom: var(--spacing-2xl); }

/* ==========================================================================
   RESPONSIVE DESIGN
   ========================================================================== */

/* Tablet (max-width: 1024px) */
@media (max-width: 1024px) {
  h1 { font-size: 2.5rem; }
  h2 { font-size: 2rem; }
  h3 { font-size: 1.75rem; }

  .hero__title { font-size: 2.5rem; }

  .footer__main {
    grid-template-columns: 1fr 1fr;
  }

  .grid-4 {
    grid-template-columns: repeat(2, 1fr);
  }
}

/* Mobile (max-width: 768px) */
@media (max-width: 768px) {
  :root {
    --spacing-lg: 24px;
    --spacing-xl: 32px;
    --spacing-2xl: 48px;
    --spacing-3xl: 64px;
  }

  h1 { font-size: 2rem; }
  h2 { font-size: 1.75rem; }
  h3 { font-size: 1.5rem; }

  .hero__title { font-size: 2rem; }
  .hero__subtitle { font-size: 1.125rem; }
  .hero__cta { flex-direction: column; }

  .header__nav-list {
    display: none;
  }

  .header__mobile-toggle {
    display: flex;
  }

  .header__nav.active .header__nav-list {
    display: flex;
    flex-direction: column;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background-color: var(--color-secondary);
    padding: var(--spacing-md);
    border-bottom: 1px solid var(--color-border);
    box-shadow: var(--shadow-lg);
  }

  .grid-2,
  .grid-3,
  .grid-4 {
    grid-template-columns: 1fr;
  }

  .footer__main {
    grid-template-columns: 1fr;
  }

  .footer__bottom {
    flex-direction: column;
    gap: var(--spacing-md);
    text-align: center;
  }

  .btn {
    width: 100%;
  }

  .stat-card__number {
    font-size: 2.5rem;
  }
}

/* Small Mobile (max-width: 480px) */
@media (max-width: 480px) {
  .container,
  .container-wide {
    padding: 0 var(--spacing-md);
  }

  .card {
    padding: var(--spacing-md);
  }

  h1 { font-size: 1.75rem; }
  .hero__title { font-size: 1.75rem; }
}