:root {
  --bg-color: #0a0a0a;
  --surface-color: #161616;
  --surface-alt: #222222;
  --text-primary: #ffffff;
  --text-secondary: #a0a0a0;
  --accent: #ffffff;
  --accent-hover: #e0e0e0;
  --border-color: #333333;
  --container-width: 1100px;
  --container-narrow: 700px;
  --spacer: 1.5rem;
  --font-main: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

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

html {
  scroll-behavior: smooth;
}

[hidden] {
  display: none !important;
}

body {
  background-color: var(--bg-color);
  color: var(--text-primary);
  font-family: var(--font-main);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

body.menu-open {
  overflow: hidden;
}

h1,
h2,
h3 {
  font-weight: 600;
  line-height: 1.2;
  letter-spacing: -0.02em;
}

a {
  color: inherit;
  text-decoration: none;
  transition: color 0.2s ease;
}

ul {
  list-style: none;
}

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

.skip-link {
  position: absolute;
  top: -100px;
  left: 1rem;
  background: var(--text-primary);
  color: var(--bg-color);
  padding: 0.5rem 1rem;
  z-index: 1000;
  transition: top 0.2s;
}

.skip-link:focus {
  top: 1rem;
}

/* Layout Utilities */
.container {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 0 1.5rem;
}

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

.section {
  padding: 6rem 0;
}

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

.section--privacy {
  padding: 3rem 0;
  border-top: 1px solid var(--border-color);
}

.section__title {
  font-size: 2.5rem;
  margin-bottom: 3rem;
  text-align: center;
}

/* Header & Nav */
.header {
  height: 80px;
  display: flex;
  align-items: center;
  border-bottom: 1px solid var(--border-color);
  position: sticky;
  top: 0;
  background: rgba(10, 10, 10, 0.8);
  backdrop-filter: blur(10px);
  z-index: 100;
}

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

.logo {
  font-size: 1.5rem;
  font-weight: 700;
  letter-spacing: -0.05em;
}

.logo span {
  font-weight: 300;
  color: var(--text-secondary);
}

.nav__list {
  display: flex;
  gap: 2rem;
  align-items: center;
}

.nav__link {
  font-size: 0.95rem;
  color: var(--text-secondary);
}

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

/* Buttons */
.btn {
  display: inline-block;
  padding: 0.8rem 1.5rem;
  background: var(--accent);
  color: var(--bg-color);
  border: none;
  font-weight: 600;
  font-size: 1rem;
  cursor: pointer;
  transition: all 0.2s ease;
  border-radius: 4px;
  text-align: center;
}

.btn:hover {
  background: var(--accent-hover);
  transform: translateY(-1px);
}

.btn--secondary {
  background: transparent;
  color: var(--text-primary);
  border: 1px solid var(--border-color);
}

.btn--secondary:hover {
  background: var(--surface-alt);
  border-color: var(--text-secondary);
}

.btn--small {
  padding: 0.5rem 1rem;
  font-size: 0.85rem;
}

.btn--full {
  width: 100%;
}

/* Hero */
.hero {
  min-height: calc(100vh - 80px);
  display: flex;
  align-items: center;
  padding: 4rem 0;
}

.hero__grid {
  display: grid;
  grid-template-columns: 1.2fr 0.8fr;
  gap: 4rem;
  align-items: center;
}

.hero__title {
  font-size: clamp(2.5rem, 5vw, 4rem);
  margin-bottom: 1.5rem;
}

.hero__subtitle {
  font-size: 1.25rem;
  color: var(--text-secondary);
  margin-bottom: 2.5rem;
  max-width: 600px;
}

.hero__actions {
  display: flex;
  gap: 1rem;
}

/* Hero Diagram - Pure CSS */
.hero__visual {
  display: flex;
  justify-content: center;
  align-items: center;
  position: relative;
}

.diagram {
  width: 300px;
  height: 300px;
  position: relative;
  display: flex;
  justify-content: center;
  align-items: center;
}

.diagram__disk {
  width: 240px;
  height: 120px;
  border: 2px solid var(--border-color);
  border-radius: 50%;
  transform: rotateX(60deg);
  position: absolute;
}

.diagram__core {
  width: 60px;
  height: 60px;
  background: var(--surface-color);
  border: 1px solid var(--text-secondary);
  transform: rotateZ(45deg);
  box-shadow: 0 0 20px rgba(255, 255, 255, 0.1);
}

.diagram__beam {
  width: 2px;
  height: 200px;
  background: linear-gradient(to top, var(--accent), transparent);
  position: absolute;
  bottom: 50%;
  transform-origin: bottom;
  animation: beam-pulse 3s infinite alternate ease-in-out;
}

@keyframes beam-pulse {
  from {
    opacity: 0.2;
    height: 180px;
  }

  to {
    opacity: 0.8;
    height: 220px;
  }
}

/* Steps */
.steps {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 3rem;
}

.step__num {
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--text-secondary);
  margin-bottom: 1rem;
  display: flex;
  align-items: center;
  gap: 10px;
}

.step__num::after {
  content: "";
  height: 1px;
  flex-grow: 1;
  background: var(--border-color);
}

.step__title {
  margin-bottom: 0.75rem;
}

.step p {
  color: var(--text-secondary);
  font-size: 1rem;
}

/* Accordion */
.accordion {
  border-top: 1px solid var(--border-color);
}

.accordion__item {
  border-bottom: 1px solid var(--border-color);
}

.accordion__header {
  width: 100%;
  padding: 1.5rem 0;
  background: none;
  border: none;
  color: var(--text-primary);
  text-align: left;
  display: flex;
  justify-content: space-between;
  align-items: center;
  cursor: pointer;
  font-size: 1.1rem;
  font-weight: 500;
}

.accordion__icon {
  width: 20px;
  height: 20px;
  position: relative;
}

.accordion__icon::before,
.accordion__icon::after {
  content: "";
  position: absolute;
  background: var(--text-secondary);
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  transition: transform 0.3s ease;
}

.accordion__icon::before {
  width: 12px;
  height: 2px;
}

.accordion__icon::after {
  width: 2px;
  height: 12px;
}

.accordion__header[aria-expanded="true"] .accordion__icon::after {
  transform: translate(-50%, -50%) rotate(90deg);
}

.accordion__body {
  padding-bottom: 1.5rem;
  color: var(--text-secondary);
}

/* Form */
.form {
  background: var(--surface-color);
  padding: 2.5rem;
  border-radius: 8px;
  border: 1px solid var(--border-color);
}

.form__group {
  margin-bottom: 1.5rem;
}

.form__label {
  display: block;
  font-size: 0.85rem;
  margin-bottom: 0.5rem;
  color: var(--text-secondary);
}

.form__input {
  width: 100%;
  background: var(--bg-color);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  padding: 0.8rem 1rem;
  border-radius: 4px;
  font-family: inherit;
  font-size: 1rem;
}

.form__input:focus {
  outline: none;
  border-color: var(--text-secondary);
}

.form__textarea {
  resize: vertical;
  min-height: 120px;
}

.form__actions {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
  margin-top: 2rem;
}

.form__status {
  margin-top: 1rem;
  font-size: 0.9rem;
  text-align: center;
}

.form__status.success {
  color: #4caf50;
}

.form__status.error {
  color: #f44336;
}

/* Footer */
.footer {
  padding: 4rem 0 2rem;
  border-top: 1px solid var(--border-color);
}

.footer__grid {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  margin-bottom: 3rem;
}

.footer__brand .logo {
  margin-bottom: 1rem;
}

.footer__brand p {
  color: var(--text-secondary);
  max-width: 250px;
}

.footer__link {
  font-size: 0.9rem;
  color: var(--text-secondary);
}

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

.footer__bottom {
  text-align: center;
  font-size: 0.85rem;
  color: var(--text-secondary);
}

.text-link {
  color: var(--text-primary);
  text-decoration: underline;
  font-size: 0.9rem;
}

/* Mobile Menu Button */
.menu-toggle {
  display: none;
  background: transparent;
  border: none;
  padding: 1rem;
  cursor: pointer;
  z-index: 200;
}

.menu-toggle__box {
  width: 24px;
  height: 18px;
  display: inline-block;
  position: relative;
}

.menu-toggle__inner,
.menu-toggle__inner::before,
.menu-toggle__inner::after {
  width: 24px;
  height: 2px;
  background-color: var(--text-primary);
  position: absolute;
  transition: transform 0.2s ease;
}

.menu-toggle__inner {
  top: 50%;
  transform: translateY(-50%);
}

.menu-toggle__inner::before {
  content: "";
  top: -8px;
}

.menu-toggle__inner::after {
  content: "";
  top: 8px;
}

.menu-toggle[aria-expanded="true"] .menu-toggle__inner {
  background-color: transparent;
}

.menu-toggle[aria-expanded="true"] .menu-toggle__inner::before {
  transform: translateY(8px) rotate(45deg);
}

.menu-toggle[aria-expanded="true"] .menu-toggle__inner::after {
  transform: translateY(-8px) rotate(-45deg);
}

/* Responsive */
@media (max-width: 900px) {
  .hero__grid {
    grid-template-columns: 1fr;
    text-align: center;
  }

  .hero__subtitle {
    margin-left: auto;
    margin-right: auto;
  }

  .hero__actions {
    justify-content: center;
  }

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

  .hero__visual {
    order: -1;
    margin-bottom: 2rem;
  }
}

@media (max-width: 768px) {
  .menu-toggle {
    display: block;
  }

  .nav {
    position: fixed;
    top: 0;
    right: -100%;
    width: 80%;
    max-width: 400px;
    height: 100vh;
    background: var(--surface-color);
    padding: 100px 2rem 2rem;
    transition: right 0.3s ease;
    box-shadow: -10px 0 30px rgba(0, 0, 0, 0.5);
  }

  .nav.is-open {
    right: 0;
  }

  .nav__list {
    flex-direction: column;
    align-items: flex-start;
    gap: 1.5rem;
  }

  .nav__link {
    font-size: 1.5rem;
    font-weight: 500;
  }

  .section__title {
    font-size: 2rem;
  }

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

@media (max-width: 480px) {
  .hero__actions {
    flex-direction: column;
  }

  .hero__title {
    font-size: 2.5rem;
  }
}