/* ============================================
   Karteichärtli Landing Page — Styles
   ============================================ */

/* --- Custom Properties --- */
:root {
  --color-primary: #2D7FF9;
  --color-primary-hover: #1A6DE0;
  --color-dark: #1A2B4A;
  --color-light-bg: #F7F9FC;
  --color-accent-bg: #EBF3FF;
  --color-text: #5A6578;
  --color-text-en: #8A95A8;
  --color-white: #FFFFFF;
  --color-border: #C0D0E0;
  --shadow-card: 0 2px 16px rgba(0, 0, 0, 0.06);
  --shadow-nav: 0 1px 8px rgba(0, 0, 0, 0.06);
  --radius: 14px;
  --max-width: 960px;
  --font-stack: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
}

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

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

body {
  font-family: var(--font-stack);
  color: var(--color-dark);
  background: var(--color-white);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

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

a {
  color: var(--color-primary);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

/* --- Utility --- */
.lang-en {
  font-size: 0.9em;
  color: var(--color-text-en);
  margin-top: 0.25em;
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

.section-heading {
  text-align: center;
  margin-bottom: 48px;
}

.section-heading h2 {
  font-size: 2rem;
  color: var(--color-dark);
  margin-bottom: 4px;
}

.section-heading .lang-en {
  font-size: 1.05rem;
}

/* ============================================
   Navigation
   ============================================ */
.site-nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255, 255, 255, 0.82);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  box-shadow: var(--shadow-nav);
}

.site-nav .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 60px;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--color-dark);
  text-decoration: none;
  letter-spacing: -0.02em;
}

.nav-logo:hover {
  text-decoration: none;
}

.nav-logo-img {
  width: 32px;
  height: 32px;
  border-radius: 7px;
}

.nav-links {
  display: flex;
  gap: 28px;
  list-style: none;
}

.nav-links a {
  font-size: 0.92rem;
  font-weight: 500;
  color: var(--color-text);
  text-decoration: none;
  transition: color 0.2s;
}

.nav-links a:hover {
  color: var(--color-primary);
  text-decoration: none;
}

.nav-hamburger {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
}

.nav-hamburger svg {
  width: 26px;
  height: 26px;
  stroke: var(--color-dark);
}

/* Mobile nav */
@media (max-width: 640px) {
  .nav-links {
    display: none;
    flex-direction: column;
    position: absolute;
    top: 60px;
    left: 0;
    right: 0;
    background: rgba(255, 255, 255, 0.96);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    box-shadow: var(--shadow-card);
    padding: 16px 24px;
    gap: 16px;
  }

  .nav-links.open {
    display: flex;
  }

  .nav-hamburger {
    display: block;
  }
}

/* ============================================
   Hero Section
   ============================================ */
.hero {
  padding: 80px 0 64px;
  background: var(--color-light-bg);
}

.hero .container {
  display: flex;
  align-items: center;
  gap: 48px;
}

.hero-text {
  flex: 1;
  min-width: 0;
}

.hero-text h1 {
  font-size: 3rem;
  font-weight: 800;
  color: var(--color-dark);
  letter-spacing: -0.03em;
  line-height: 1.15;
  margin-bottom: 12px;
}

.hero-tagline {
  font-size: 1.3rem;
  color: var(--color-text);
  margin-bottom: 4px;
}

.hero-description {
  font-size: 1.05rem;
  color: var(--color-text);
  margin-top: 16px;
  margin-bottom: 4px;
}

.hero-cta {
  margin-top: 28px;
}

.app-store-badge {
  display: inline-block;
  transition: opacity 0.2s;
}

.app-store-badge:hover {
  opacity: 0.8;
}

.app-store-badge img,
.app-store-badge svg {
  height: 48px;
  width: auto;
}

.hero-screenshot {
  flex-shrink: 0;
}

/* ============================================
   Screenshot Placeholder
   ============================================ */
.screenshot-placeholder {
  width: 260px;
  /* 9:19.5 aspect ratio */
  aspect-ratio: 9 / 19.5;
  border: 2px dashed var(--color-border);
  border-radius: 28px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-text-en);
  font-size: 0.95rem;
  background: var(--color-white);
  flex-shrink: 0;
}

.screenshot-placeholder.hero-phone {
  width: 280px;
}

.hero-phone-img {
  width: 280px;
  border-radius: 28px;
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.12);
}

.screenshot-img {
  width: 260px;
  border-radius: 24px;
  box-shadow: 0 4px 24px rgba(0, 0, 0, 0.1);
  flex-shrink: 0;
}

/* ============================================
   Features Section
   ============================================ */
.features {
  padding: 80px 0;
}

.features-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
}

.feature-card {
  background: var(--color-white);
  border-radius: var(--radius);
  box-shadow: var(--shadow-card);
  padding: 32px 28px;
  text-align: center;
}

.feature-icon {
  font-size: 2.2rem;
  margin-bottom: 14px;
}

.feature-card h3 {
  font-size: 1.15rem;
  color: var(--color-dark);
  margin-bottom: 2px;
}

.feature-card .lang-en {
  margin-bottom: 12px;
}

.feature-card p:not(.lang-en) {
  font-size: 0.95rem;
  color: var(--color-text);
}

@media (max-width: 640px) {
  .features-grid {
    grid-template-columns: 1fr;
  }
}

/* ============================================
   Screenshots Section
   ============================================ */
.screenshots {
  padding: 80px 0;
  background: var(--color-light-bg);
}

.screenshots-row {
  display: flex;
  gap: 24px;
  justify-content: center;
  flex-wrap: wrap;
}

.screenshot-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
}

.screenshot-caption {
  text-align: center;
  font-size: 0.9rem;
  color: var(--color-text);
}

.screenshot-caption .lang-en {
  font-size: 0.85rem;
}

@media (max-width: 640px) {
  .screenshots-row {
    flex-wrap: nowrap;
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
    scroll-snap-type: x mandatory;
    justify-content: flex-start;
    padding-bottom: 12px;
  }

  .screenshot-item {
    scroll-snap-align: center;
  }

  .screenshot-placeholder {
    width: 220px;
  }

  .screenshot-img {
    width: 220px;
  }
}

/* ============================================
   Import Section
   ============================================ */
.import-section {
  padding: 80px 0;
}

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

.import-content > p {
  text-align: center;
  font-size: 1.05rem;
  color: var(--color-text);
}

.sample-decks-heading {
  font-size: 1.15rem;
  color: var(--color-dark);
  text-align: center;
  margin-top: 36px;
  margin-bottom: 4px;
}

.sample-decks-heading + .lang-en {
  text-align: center;
  margin-bottom: 20px;
}

.sample-decks-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 14px;
  margin-bottom: 24px;
}

.sample-deck-card {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 16px 18px;
  background: var(--color-white);
  border-radius: 12px;
  box-shadow: var(--shadow-card);
  border-left: 4px solid var(--deck-color, var(--color-primary));
  color: var(--color-dark);
}

.sample-deck-flag {
  font-size: 1.6rem;
  flex-shrink: 0;
}

.sample-deck-info {
  min-width: 0;
}

.sample-deck-name {
  display: block;
  font-weight: 600;
  font-size: 0.95rem;
  line-height: 1.3;
}

.sample-deck-meta {
  display: block;
  font-size: 0.8rem;
  color: var(--color-text-en);
  margin-top: 2px;
}

.sample-deck-links {
  display: flex;
  gap: 10px;
  margin-top: 6px;
}

.sample-deck-links a {
  display: inline-block;
  padding: 3px 12px;
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--color-primary);
  background: var(--color-accent-bg);
  border-radius: 6px;
  text-decoration: none;
  transition: background 0.2s;
}

.sample-deck-links a:hover {
  background: #D6E8FF;
  text-decoration: none;
}

.import-hint {
  text-align: center;
  font-size: 0.92rem;
  color: var(--color-text);
  margin-bottom: 2px;
}

.import-details {
  margin-top: 32px;
  border: 1px solid #E5EAF0;
  border-radius: 12px;
  padding: 0;
}

.import-details summary {
  padding: 14px 20px;
  font-weight: 600;
  font-size: 0.95rem;
  color: var(--color-dark);
  cursor: pointer;
  list-style: none;
}

.import-details summary::-webkit-details-marker {
  display: none;
}

.import-details summary::before {
  content: "▸ ";
  color: var(--color-primary);
}

.import-details[open] summary::before {
  content: "▾ ";
}

.import-details[open] summary {
  border-bottom: 1px solid #E5EAF0;
}

.import-details .code-label,
.import-details .code-block,
.import-details .import-note {
  margin-left: 20px;
  margin-right: 20px;
}

.import-details .import-note {
  margin-bottom: 20px;
}

@media (max-width: 640px) {
  .sample-decks-grid {
    grid-template-columns: 1fr;
  }
}

.code-block {
  background: #1E293B;
  color: #E2E8F0;
  border-radius: 12px;
  padding: 20px 24px;
  margin: 24px 0 12px;
  overflow-x: auto;
  font-family: 'SF Mono', SFMono-Regular, Consolas, 'Liberation Mono', Menlo, monospace;
  font-size: 0.88rem;
  line-height: 1.7;
}

.code-label {
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--color-text-en);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-top: 28px;
  margin-bottom: 0;
}

.import-note {
  margin-top: 24px;
  padding: 16px 20px;
  background: var(--color-accent-bg);
  border-radius: 10px;
  font-size: 0.95rem;
  color: var(--color-dark);
}

.btn-secondary {
  display: inline-block;
  margin-top: 20px;
  padding: 10px 22px;
  background: var(--color-accent-bg);
  color: var(--color-primary);
  font-weight: 600;
  font-size: 0.95rem;
  border: none;
  border-radius: 8px;
  cursor: pointer;
  transition: background 0.2s;
  text-decoration: none;
}

.btn-secondary:hover {
  background: #D6E8FF;
  text-decoration: none;
}

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

/* ============================================
   Privacy Section
   ============================================ */
.privacy {
  padding: 80px 0;
  background: var(--color-accent-bg);
}

.privacy-list {
  max-width: 600px;
  margin: 0 auto;
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.privacy-list li {
  display: flex;
  align-items: flex-start;
  gap: 14px;
  font-size: 1.05rem;
  color: var(--color-dark);
}

.privacy-icon {
  font-size: 1.4rem;
  flex-shrink: 0;
  line-height: 1.5;
}

.privacy-text .lang-en {
  font-size: 0.88rem;
}

/* ============================================
   Feedback Section
   ============================================ */
.feedback {
  padding: 80px 0;
}

.feedback-form-wrapper {
  max-width: 560px;
  margin: 0 auto;
  background: var(--color-white);
  border-radius: var(--radius);
  box-shadow: var(--shadow-card);
  padding: 36px 32px;
}

.form-group {
  margin-bottom: 20px;
}

.form-group label {
  display: block;
  font-weight: 600;
  font-size: 0.92rem;
  color: var(--color-dark);
  margin-bottom: 6px;
}

.form-group label .lang-en {
  font-weight: 400;
  font-size: 0.82rem;
}

.form-group input,
.form-group textarea {
  width: 100%;
  padding: 10px 14px;
  border: 1.5px solid #D0D9E6;
  border-radius: 8px;
  font-family: var(--font-stack);
  font-size: 0.95rem;
  color: var(--color-dark);
  background: var(--color-white);
  transition: border-color 0.2s;
}

.form-group input:focus,
.form-group textarea:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(45, 127, 249, 0.12);
}

.form-group textarea {
  resize: vertical;
  min-height: 120px;
}

.captcha-wrapper {
  margin-bottom: 20px;
}

.btn-submit {
  width: 100%;
  padding: 12px;
  background: var(--color-primary);
  color: var(--color-white);
  font-family: var(--font-stack);
  font-size: 1rem;
  font-weight: 600;
  border: none;
  border-radius: 8px;
  cursor: pointer;
  transition: background 0.2s, opacity 0.2s;
}

.btn-submit:hover:not(:disabled) {
  background: var(--color-primary-hover);
}

.btn-submit:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.form-message {
  margin-top: 16px;
  padding: 12px 16px;
  border-radius: 8px;
  font-size: 0.95rem;
  display: none;
}

.form-message.success {
  display: block;
  background: #E6F9ED;
  color: #1A7A3A;
}

.form-message.error {
  display: block;
  background: #FDE8E8;
  color: #B91C1C;
}

/* ============================================
   CTA Section
   ============================================ */
.cta {
  padding: 80px 0;
  background: var(--color-light-bg);
  text-align: center;
}

.cta h2 {
  font-size: 2rem;
  color: var(--color-dark);
  margin-bottom: 4px;
}

.cta .lang-en {
  font-size: 1.05rem;
  margin-bottom: 28px;
}

.cta-availability {
  margin-top: 16px;
  font-size: 0.92rem;
  color: var(--color-text);
}

/* ============================================
   Footer
   ============================================ */
.site-footer {
  padding: 32px 0;
  border-top: 1px solid #E5EAF0;
}

.site-footer .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
}

.footer-copy {
  font-size: 0.88rem;
  color: var(--color-text-en);
}

.footer-links {
  display: flex;
  gap: 20px;
  list-style: none;
}

.footer-links a {
  font-size: 0.88rem;
  color: var(--color-text);
}

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

.footer-love {
  width: 100%;
  text-align: center;
  margin-top: 8px;
  font-size: 0.82rem;
  color: var(--color-text-en);
}

/* ============================================
   Scroll Fade-in Animation
   ============================================ */
.fade-in {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ============================================
   Responsive: Hero
   ============================================ */
@media (max-width: 768px) {
  .hero .container {
    flex-direction: column;
    text-align: center;
  }

  .hero-text h1 {
    font-size: 2.2rem;
  }

  .hero-tagline {
    font-size: 1.1rem;
  }

  .hero-screenshot {
    margin-top: 16px;
  }

  .screenshot-placeholder.hero-phone {
    width: 220px;
  }

  .hero-phone-img {
    width: 220px;
  }
}

@media (max-width: 640px) {
  .site-footer .container {
    flex-direction: column;
    text-align: center;
  }

  .footer-links {
    justify-content: center;
  }

  .feedback-form-wrapper {
    padding: 28px 20px;
  }
}