/* ============================================
   Knoito Website — Design Tokens & Styles
   Derived from iOS app design system
   ============================================ */

/* --- CSS Variables (Design Tokens) --- */
:root {
  /* Accent */
  --accent: #007AFF;
  --accent-light: #30B0FF;
  --accent-gradient: linear-gradient(135deg, #007AFF, #30B0FF);

  /* Light mode (default) */
  --bg: #F2F2F7;
  --bg-card: #FFFFFF;
  --bg-hero: #0B1A2E;
  --text-primary: #141619;
  --text-secondary: #73757F;
  --text-on-dark: #F5F5F8;
  --text-on-dark-secondary: #98989A;
  --divider: rgba(0, 0, 0, 0.08);
  --shadow: rgba(0, 0, 0, 0.08);

  /* Spacing */
  --space-xs: 4px;
  --space-sm: 8px;
  --space-md: 12px;
  --space-lg: 16px;
  --space-xl: 24px;
  --space-2xl: 32px;
  --space-3xl: 48px;
  --space-4xl: 64px;

  /* Radius */
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 24px;

  /* Typography */
  --font: -apple-system, BlinkMacSystemFont, 'SF Pro Rounded', 'SF Pro Display', 'Segoe UI', system-ui, sans-serif;
  --font-size-hero: clamp(2.5rem, 5vw, 3.5rem);
  --font-size-h2: clamp(1.75rem, 3vw, 2.25rem);
  --font-size-h3: 1.25rem;
  --font-size-body: 1.0625rem;
  --font-size-small: 0.875rem;
  --font-size-micro: 0.75rem;

  /* Layout */
  --max-width: 1120px;
  --nav-height: 64px;
}

/* --- Dark mode --- */
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #000000;
    --bg-card: #1C1C1E;
    --text-primary: #F5F5F8;
    --text-secondary: #98989A;
    --divider: rgba(255, 255, 255, 0.08);
    --shadow: rgba(0, 0, 0, 0.4);
  }
}

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

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

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

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

a {
  color: var(--accent);
  text-decoration: none;
  transition: opacity 0.2s;
}

a:hover {
  opacity: 0.8;
}

/* --- Utility --- */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space-xl);
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  border: 0;
}

/* --- Navigation --- */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--nav-height);
  background: rgba(11, 26, 46, 0.92);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  z-index: 100;
  border-bottom: 1px solid rgba(255, 255, 255, 0.06);
}

.nav__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}

.nav__logo {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-on-dark);
  text-decoration: none;
}

.nav__logo img {
  width: 36px;
  height: 36px;
  border-radius: var(--radius-sm);
}

.nav__links {
  display: flex;
  align-items: center;
  gap: var(--space-xl);
  list-style: none;
}

.nav__links a {
  color: var(--text-on-dark-secondary);
  font-size: var(--font-size-small);
  font-weight: 500;
  transition: color 0.2s;
}

.nav__links a:hover {
  color: var(--text-on-dark);
  opacity: 1;
}

.nav__toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--space-sm);
}

.nav__toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--text-on-dark);
  margin: 5px 0;
  border-radius: 2px;
  transition: transform 0.3s, opacity 0.3s;
}

/* Mobile nav */
@media (max-width: 768px) {
  .nav__toggle {
    display: block;
  }

  .nav__links {
    position: fixed;
    top: var(--nav-height);
    left: 0;
    right: 0;
    flex-direction: column;
    background: rgba(11, 26, 46, 0.98);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    padding: var(--space-xl);
    gap: var(--space-lg);
    transform: translateY(-100%);
    opacity: 0;
    pointer-events: none;
    transition: transform 0.3s, opacity 0.3s;
  }

  .nav__links.active {
    transform: translateY(0);
    opacity: 1;
    pointer-events: all;
  }

  .nav__links a {
    font-size: var(--font-size-body);
  }
}

/* --- Hero Section --- */
.hero {
  background: var(--bg-hero);
  padding: calc(var(--nav-height) + var(--space-4xl)) 0 var(--space-4xl);
  text-align: center;
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  top: -50%;
  left: -50%;
  width: 200%;
  height: 200%;
  background: radial-gradient(ellipse at 50% 80%, rgba(0, 122, 255, 0.12) 0%, transparent 60%);
  pointer-events: none;
}

.hero__content {
  position: relative;
  z-index: 1;
}

.hero__badge {
  display: inline-block;
  background: rgba(0, 122, 255, 0.15);
  color: var(--accent-light);
  font-size: var(--font-size-small);
  font-weight: 600;
  padding: var(--space-xs) var(--space-lg);
  border-radius: 100px;
  margin-bottom: var(--space-xl);
  border: 1px solid rgba(0, 122, 255, 0.2);
}

.hero__title {
  font-size: var(--font-size-hero);
  font-weight: 800;
  color: var(--text-on-dark);
  line-height: 1.15;
  letter-spacing: -0.02em;
  margin-bottom: var(--space-lg);
}

.hero__title .gradient-text {
  background: var(--accent-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero__subtitle {
  font-size: clamp(1.1rem, 2vw, 1.35rem);
  color: var(--text-on-dark-secondary);
  max-width: 580px;
  margin: 0 auto var(--space-2xl);
  line-height: 1.5;
}

/* --- Email Form --- */
.signup-form {
  display: flex;
  gap: var(--space-sm);
  max-width: 460px;
  margin: 0 auto var(--space-lg);
}

.signup-form input[type="email"] {
  flex: 1;
  padding: var(--space-md) var(--space-lg);
  border: 1px solid rgba(255, 255, 255, 0.12);
  border-radius: var(--radius-md);
  background: rgba(255, 255, 255, 0.06);
  color: var(--text-on-dark);
  font-family: var(--font);
  font-size: var(--font-size-body);
  outline: none;
  transition: border-color 0.2s, background 0.2s;
}

.signup-form input[type="email"]::placeholder {
  color: var(--text-on-dark-secondary);
}

.signup-form input[type="email"]:focus {
  border-color: var(--accent);
  background: rgba(255, 255, 255, 0.1);
}

.signup-form button {
  padding: var(--space-md) var(--space-xl);
  background: var(--accent-gradient);
  color: #FFFFFF;
  font-family: var(--font);
  font-size: var(--font-size-body);
  font-weight: 600;
  border: none;
  border-radius: var(--radius-md);
  cursor: pointer;
  white-space: nowrap;
  transition: transform 0.15s, box-shadow 0.2s;
}

.signup-form button:hover {
  transform: translateY(-1px);
  box-shadow: 0 4px 16px rgba(0, 122, 255, 0.35);
}

.signup-form button:active {
  transform: translateY(0);
}

.hero__note {
  font-size: var(--font-size-small);
  color: var(--text-on-dark-secondary);
  opacity: 0.7;
}

@media (max-width: 520px) {
  .signup-form {
    flex-direction: column;
  }

  .signup-form button {
    width: 100%;
  }
}

/* --- Features Section --- */
.features {
  padding: var(--space-4xl) 0;
}

.features__header {
  text-align: center;
  margin-bottom: var(--space-3xl);
}

.features__header h2 {
  font-size: var(--font-size-h2);
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: var(--space-sm);
}

.features__header p {
  color: var(--text-secondary);
  max-width: 520px;
  margin: 0 auto;
}

.features__grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-xl);
}

.feature-card {
  background: var(--bg-card);
  border-radius: var(--radius-xl);
  padding: var(--space-2xl);
  box-shadow: 0 1px 3px var(--shadow);
  transition: transform 0.2s, box-shadow 0.2s;
}

.feature-card:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 24px var(--shadow);
}

.feature-card__icon {
  width: 48px;
  height: 48px;
  border-radius: var(--radius-md);
  background: rgba(0, 122, 255, 0.1);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  margin-bottom: var(--space-lg);
}

.feature-card h3 {
  font-size: var(--font-size-h3);
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: var(--space-sm);
}

.feature-card p {
  color: var(--text-secondary);
  font-size: var(--font-size-small);
  line-height: 1.6;
}

@media (max-width: 768px) {
  .features__grid {
    grid-template-columns: 1fr;
    gap: var(--space-lg);
  }
}

/* --- CTA Section --- */
.cta {
  padding: var(--space-4xl) 0;
  text-align: center;
}

.cta__card {
  background: var(--bg-hero);
  border-radius: var(--radius-xl);
  padding: var(--space-3xl) var(--space-2xl);
  position: relative;
  overflow: hidden;
}

.cta__card::before {
  content: '';
  position: absolute;
  top: -50%;
  left: -50%;
  width: 200%;
  height: 200%;
  background: radial-gradient(ellipse at 50% 100%, rgba(0, 122, 255, 0.1) 0%, transparent 50%);
  pointer-events: none;
}

.cta__card h2 {
  font-size: var(--font-size-h2);
  font-weight: 700;
  color: var(--text-on-dark);
  margin-bottom: var(--space-sm);
  position: relative;
}

.cta__card p {
  color: var(--text-on-dark-secondary);
  margin-bottom: var(--space-2xl);
  position: relative;
}

.cta__card .signup-form {
  position: relative;
}

/* --- Footer --- */
.footer {
  padding: var(--space-2xl) 0;
  border-top: 1px solid var(--divider);
}

.footer__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: var(--space-lg);
}

.footer__copyright {
  color: var(--text-secondary);
  font-size: var(--font-size-small);
}

.footer__links {
  display: flex;
  gap: var(--space-xl);
  list-style: none;
}

.footer__links a {
  color: var(--text-secondary);
  font-size: var(--font-size-small);
  transition: color 0.2s;
}

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

@media (max-width: 520px) {
  .footer__inner {
    flex-direction: column;
    text-align: center;
  }
}

/* ============================================
   Legal Pages (Privacy, Terms)
   ============================================ */
.legal {
  padding: calc(var(--nav-height) + var(--space-3xl)) 0 var(--space-4xl);
}

.legal__content {
  max-width: 720px;
  margin: 0 auto;
}

.legal__content h1 {
  font-size: var(--font-size-h2);
  font-weight: 700;
  margin-bottom: var(--space-sm);
}

.legal__content .last-updated {
  color: var(--text-secondary);
  font-size: var(--font-size-small);
  margin-bottom: var(--space-3xl);
}

.legal__content h2 {
  font-size: var(--font-size-h3);
  font-weight: 600;
  margin-top: var(--space-2xl);
  margin-bottom: var(--space-md);
}

.legal__content p {
  color: var(--text-secondary);
  margin-bottom: var(--space-lg);
  line-height: 1.7;
}

.legal__content ul {
  color: var(--text-secondary);
  margin-bottom: var(--space-lg);
  padding-left: var(--space-xl);
  line-height: 1.8;
}

.legal__content li {
  margin-bottom: var(--space-xs);
}

.legal__content a {
  color: var(--accent);
}

.legal__content strong {
  color: var(--text-primary);
  font-weight: 600;
}