/* ==========================================================================
   LearnDeck Website – Stylesheet
   Light/Dark-Theme über CSS Custom Properties ([data-theme="dark"])
   ========================================================================== */

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: 90px;
}

/* ---------- Theme Tokens ---------- */
:root {
  --font-sans: -apple-system, BlinkMacSystemFont, "SF Pro Display", "Segoe UI",
    Roboto, Helvetica, Arial, sans-serif;

  /* Markenfarbe aus dem App-Logo (icon.json: srgb 0 / 0.533 / 1.0) */
  --accent: #0088ff;
  --accent-2: #6a5cf5;
  --accent-3: #2dd4bf;
  --gradient: linear-gradient(120deg, var(--accent), var(--accent-2));
  --gradient-text: linear-gradient(
    100deg,
    var(--accent) 0%,
    var(--accent-2) 50%,
    var(--accent-3) 100%
  );

  --bg: #f4f8fd;
  --bg-elevated: #ffffff;
  --bg-soft: #e9f1fb;
  --text: #0f1726;
  --text-muted: #54607a;
  --border: rgba(15, 23, 38, 0.08);
  --shadow: 0 8px 32px rgba(0, 90, 170, 0.08);
  --shadow-lg: 0 24px 64px rgba(0, 90, 170, 0.14);
  --nav-bg: rgba(255, 255, 255, 0.72);
  --glow-1: rgba(0, 136, 255, 0.18);
  --glow-2: rgba(106, 92, 245, 0.13);
  --glow-3: rgba(45, 212, 191, 0.12);
  --card-hover-border: rgba(0, 136, 255, 0.38);
}

[data-theme="dark"] {
  --bg: #0a0f18;
  --bg-elevated: #111a28;
  --bg-soft: #152133;
  --text: #ecf3fc;
  --text-muted: #93a3bd;
  --border: rgba(236, 243, 252, 0.09);
  --shadow: 0 8px 32px rgba(0, 0, 0, 0.35);
  --shadow-lg: 0 24px 64px rgba(0, 0, 0, 0.5);
  --nav-bg: rgba(10, 15, 24, 0.72);
  --glow-1: rgba(0, 136, 255, 0.22);
  --glow-2: rgba(106, 92, 245, 0.15);
  --glow-3: rgba(45, 212, 191, 0.1);
  --card-hover-border: rgba(64, 165, 255, 0.45);
}

body {
  font-family: var(--font-sans);
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  transition: background 0.3s ease, color 0.3s ease;
  overflow-x: hidden;
}

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

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

ul {
  list-style: none;
}

button {
  font-family: inherit;
  cursor: pointer;
}

.container {
  width: min(1140px, 92%);
  margin: 0 auto;
}

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

/* ---------- Navigation ---------- */
.site-nav {
  position: fixed;
  inset: 0 0 auto 0;
  z-index: 100;
  backdrop-filter: blur(18px);
  -webkit-backdrop-filter: blur(18px);
  background: var(--nav-bg);
  border-bottom: 1px solid var(--border);
}

.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  height: 68px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  font-weight: 700;
  font-size: 1.15rem;
  letter-spacing: -0.02em;
}

.brand-logo {
  width: 34px;
  height: 34px;
  border-radius: 9px;
  flex-shrink: 0;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 1.6rem;
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--text-muted);
}

.nav-links a {
  transition: color 0.2s ease;
}

.nav-links a:hover {
  color: var(--text);
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 0.6rem;
}

.lang-select {
  appearance: none;
  -webkit-appearance: none;
  background: var(--bg-soft);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 0.45rem 1.9rem 0.45rem 0.75rem;
  font-size: 0.88rem;
  font-weight: 600;
  cursor: pointer;
  background-image: url("data:image/svg+xml;charset=utf-8,%3Csvg xmlns='http://www.w3.org/2000/svg' width='10' height='6' viewBox='0 0 10 6'%3E%3Cpath d='M1 1l4 4 4-4' fill='none' stroke='%23888da8' stroke-width='1.6' stroke-linecap='round'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 0.7rem center;
  transition: border-color 0.2s ease;
}

.lang-select:hover {
  border-color: var(--card-hover-border);
}

.theme-toggle {
  display: grid;
  place-items: center;
  width: 38px;
  height: 38px;
  border-radius: 10px;
  border: 1px solid var(--border);
  background: var(--bg-soft);
  color: var(--text);
  transition: border-color 0.2s ease, transform 0.2s ease;
}

.theme-toggle:hover {
  border-color: var(--card-hover-border);
  transform: translateY(-1px);
}

.theme-toggle .icon-sun,
.theme-toggle .icon-moon {
  width: 18px;
  height: 18px;
}

[data-theme="dark"] .theme-toggle .icon-moon,
:root:not([data-theme="dark"]) .theme-toggle .icon-sun {
  display: none;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.55rem;
  border: none;
  border-radius: 12px;
  font-weight: 600;
  font-size: 0.95rem;
  padding: 0.7rem 1.3rem;
  transition: transform 0.2s ease, box-shadow 0.2s ease, opacity 0.2s ease;
}

.btn-primary {
  background: var(--gradient);
  color: #fff;
  box-shadow: 0 8px 24px rgba(0, 136, 255, 0.35);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 12px 32px rgba(0, 136, 255, 0.45);
}

.btn-nav {
  padding: 0.55rem 1.05rem;
  font-size: 0.88rem;
}

/* ---------- App-Store-Badge ---------- */
.appstore-badge {
  display: inline-flex;
  align-items: center;
  transition: transform 0.2s ease, opacity 0.2s ease;
}

.appstore-badge:hover {
  transform: translateY(-2px);
  opacity: 0.9;
}

.appstore-badge img {
  height: 52px;
  width: auto;
}

.appstore-badge-nav img {
  height: 38px;
}

/* ---------- Hero ---------- */
.hero {
  position: relative;
  padding: 11rem 0 7rem;
  text-align: center;
  overflow: hidden;
}

.hero-glow {
  position: absolute;
  border-radius: 50%;
  filter: blur(90px);
  pointer-events: none;
}

.hero-glow.g1 {
  width: 520px;
  height: 520px;
  background: var(--glow-1);
  top: -120px;
  left: -120px;
}

.hero-glow.g2 {
  width: 460px;
  height: 460px;
  background: var(--glow-2);
  top: 40px;
  right: -140px;
}

.hero-glow.g3 {
  width: 380px;
  height: 380px;
  background: var(--glow-3);
  bottom: -160px;
  left: 35%;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.4rem 1rem;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: var(--bg-elevated);
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-muted);
  box-shadow: var(--shadow);
  margin-bottom: 1.8rem;
}

.hero-badge .dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--accent-3);
}

.hero-badge .badge-highlight {
  background: var(--gradient-text);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero h1 {
  font-size: clamp(2.6rem, 7vw, 4.8rem);
  line-height: 1.08;
  letter-spacing: -0.035em;
  font-weight: 800;
}

.hero-subtitle {
  max-width: 640px;
  margin: 1.6rem auto 2.4rem;
  font-size: clamp(1.02rem, 2vw, 1.2rem);
  color: var(--text-muted);
}

.hero-actions {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 1rem;
  flex-wrap: wrap;
}

.hero-meta {
  display: flex;
  justify-content: center;
  gap: 1.6rem;
  flex-wrap: wrap;
  margin-top: 2.4rem;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-muted);
}

.hero-meta span {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
}

.hero-meta svg {
  width: 15px;
  height: 15px;
  color: var(--accent);
}

/* ---------- Sections ---------- */
section {
  padding: 5.5rem 0;
}

.section-head {
  text-align: center;
  max-width: 640px;
  margin: 0 auto 3.5rem;
}

.section-kicker {
  display: inline-block;
  font-size: 0.82rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--accent);
  margin-bottom: 0.8rem;
}

.section-head h2 {
  font-size: clamp(1.8rem, 4vw, 2.6rem);
  letter-spacing: -0.025em;
  line-height: 1.15;
}

.section-head p {
  margin-top: 1rem;
  color: var(--text-muted);
  font-size: 1.05rem;
}

/* ---------- Feature Grid ---------- */
.feature-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.4rem;
}

.feature-card {
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: 20px;
  padding: 1.8rem;
  box-shadow: var(--shadow);
  transition: transform 0.25s ease, border-color 0.25s ease,
    box-shadow 0.25s ease;
}

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

.feature-icon {
  display: grid;
  place-items: center;
  width: 48px;
  height: 48px;
  border-radius: 14px;
  background: var(--gradient);
  color: #fff;
  margin-bottom: 1.2rem;
}

.feature-icon svg {
  width: 24px;
  height: 24px;
}

.feature-card h3 {
  font-size: 1.12rem;
  margin-bottom: 0.5rem;
  letter-spacing: -0.01em;
}

.feature-card p {
  font-size: 0.93rem;
  color: var(--text-muted);
}

/* ---------- Screens / Showcase ---------- */
.showcase {
  background: var(--bg-soft);
  border-block: 1px solid var(--border);
}

.showcase-item {
  display: grid;
  grid-template-columns: 1fr 1fr;
  align-items: center;
  gap: 4rem;
  padding: 3.5rem 0;
}

.showcase-item:nth-child(even) .showcase-media {
  order: -1;
}

.showcase-num {
  font-size: 0.95rem;
  font-weight: 800;
  color: var(--accent);
  letter-spacing: 0.08em;
}

.showcase-copy h3 {
  font-size: clamp(1.4rem, 3vw, 1.9rem);
  letter-spacing: -0.02em;
  margin: 0.6rem 0 1rem;
  line-height: 1.2;
}

.showcase-copy p {
  color: var(--text-muted);
  margin-bottom: 1.4rem;
}

.showcase-list li {
  display: flex;
  align-items: flex-start;
  gap: 0.65rem;
  font-size: 0.95rem;
  font-weight: 500;
  padding: 0.35rem 0;
}

.showcase-list svg {
  width: 18px;
  height: 18px;
  color: var(--accent-3);
  flex-shrink: 0;
  margin-top: 0.2rem;
}

/* Phone-Mockup (Platzhalter, bis echte Screenshots vorliegen) */
.showcase-media {
  display: flex;
  justify-content: center;
}

.phone-frame {
  width: min(290px, 80%);
  aspect-ratio: 9 / 19;
  border-radius: 42px;
  border: 10px solid var(--text);
  background: var(--bg-elevated);
  box-shadow: var(--shadow-lg);
  position: relative;
  overflow: hidden;
}

[data-theme="dark"] .phone-frame {
  border-color: #2a2e45;
}

.phone-notch {
  position: absolute;
  top: 10px;
  left: 50%;
  transform: translateX(-50%);
  width: 38%;
  height: 24px;
  border-radius: 999px;
  background: var(--text);
  z-index: 2;
}

[data-theme="dark"] .phone-notch {
  background: #2a2e45;
}

.phone-screen {
  position: absolute;
  inset: 0;
  display: grid;
  place-items: center;
  text-align: center;
  padding: 1.5rem;
  background: linear-gradient(160deg, var(--glow-1), var(--glow-2) 55%, var(--glow-3));
  color: var(--text-muted);
  font-size: 0.85rem;
  font-weight: 600;
}

/* ---------- Privacy Banner ---------- */
.privacy-banner .privacy-card {
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: 28px;
  box-shadow: var(--shadow);
  text-align: center;
  padding: 3.5rem 2rem;
  position: relative;
  overflow: hidden;
}

.privacy-card::before {
  content: "";
  position: absolute;
  inset: 0 0 auto 0;
  height: 4px;
  background: var(--gradient-text);
}

.privacy-card h2 {
  font-size: clamp(1.6rem, 3.5vw, 2.2rem);
  letter-spacing: -0.02em;
}

.privacy-card > p {
  max-width: 620px;
  margin: 1rem auto 1.8rem;
  color: var(--text-muted);
}

.privacy-badges {
  display: flex;
  justify-content: center;
  gap: 0.8rem;
  flex-wrap: wrap;
  margin-bottom: 1.8rem;
}

.privacy-badges span {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  padding: 0.45rem 1rem;
  border-radius: 999px;
  background: var(--bg-soft);
  border: 1px solid var(--border);
  font-size: 0.85rem;
  font-weight: 600;
}

.privacy-badges svg {
  width: 14px;
  height: 14px;
  color: var(--accent-3);
}

.privacy-link {
  font-weight: 600;
  color: var(--accent);
  transition: opacity 0.2s ease;
}

.privacy-link:hover {
  opacity: 0.75;
}

/* ---------- CTA ---------- */
.cta-section {
  text-align: center;
  position: relative;
  overflow: hidden;
}

.cta-section h2 {
  font-size: clamp(1.8rem, 4vw, 2.6rem);
  letter-spacing: -0.025em;
}

.cta-section p {
  max-width: 540px;
  margin: 1rem auto 2rem;
  color: var(--text-muted);
}

/* ---------- Footer ---------- */
.site-footer {
  border-top: 1px solid var(--border);
  background: var(--bg-elevated);
  padding: 3.5rem 0 2rem;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 2.5rem;
  margin-bottom: 2.5rem;
}

.footer-brand p {
  margin-top: 0.8rem;
  font-size: 0.92rem;
  color: var(--text-muted);
  max-width: 280px;
}

.footer-col h4 {
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-muted);
  margin-bottom: 1rem;
}

.footer-col li {
  margin-bottom: 0.6rem;
}

.footer-col a {
  font-size: 0.93rem;
  color: var(--text-muted);
  transition: color 0.2s ease;
}

.footer-col a:hover {
  color: var(--text);
}

.footer-bottom {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  flex-wrap: wrap;
  padding-top: 1.8rem;
  border-top: 1px solid var(--border);
  font-size: 0.85rem;
  color: var(--text-muted);
}

.footer-lang {
  display: flex;
  align-items: center;
  gap: 0.6rem;
}

/* ---------- Support Page ---------- */
.page-hero {
  position: relative;
  padding: 10rem 0 4rem;
  text-align: center;
  overflow: hidden;
}

.page-hero h1 {
  font-size: clamp(2.2rem, 5vw, 3.4rem);
  letter-spacing: -0.03em;
  line-height: 1.1;
}

.page-hero p {
  max-width: 600px;
  margin: 1.2rem auto 0;
  color: var(--text-muted);
  font-size: 1.08rem;
}

.topic-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1.4rem;
}

.topic-card {
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: 20px;
  padding: 1.6rem;
  box-shadow: var(--shadow);
  transition: transform 0.25s ease, border-color 0.25s ease;
}

.topic-card:hover {
  transform: translateY(-4px);
  border-color: var(--card-hover-border);
}

.topic-card .feature-icon {
  width: 44px;
  height: 44px;
  margin-bottom: 1rem;
}

.topic-card h3 {
  font-size: 1.02rem;
  margin-bottom: 0.4rem;
}

.topic-card p {
  font-size: 0.88rem;
  color: var(--text-muted);
}

/* FAQ Accordion */
.faq-list {
  max-width: 760px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 0.9rem;
}

.faq-item {
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: 16px;
  overflow: hidden;
  transition: border-color 0.25s ease;
}

.faq-item[open] {
  border-color: var(--card-hover-border);
}

.faq-item summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 1.15rem 1.4rem;
  font-weight: 600;
  font-size: 1rem;
  cursor: pointer;
  list-style: none;
}

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

.faq-chevron {
  width: 18px;
  height: 18px;
  flex-shrink: 0;
  color: var(--text-muted);
  transition: transform 0.25s ease;
}

.faq-item[open] .faq-chevron {
  transform: rotate(180deg);
}

.faq-answer {
  padding: 0 1.4rem 1.3rem;
  color: var(--text-muted);
  font-size: 0.95rem;
}

/* Support Form */
.support-form-wrap {
  display: grid;
  grid-template-columns: 1.4fr 1fr;
  gap: 2.5rem;
  align-items: start;
}

.form-card,
.contact-card {
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: 24px;
  padding: 2.2rem;
  box-shadow: var(--shadow);
}

.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.2rem;
}

.form-group {
  margin-bottom: 1.2rem;
}

.form-group label {
  display: block;
  font-size: 0.88rem;
  font-weight: 600;
  margin-bottom: 0.45rem;
}

.form-group input,
.form-group select,
.form-group textarea {
  width: 100%;
  font-family: inherit;
  font-size: 0.95rem;
  color: var(--text);
  background: var(--bg-soft);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 0.75rem 1rem;
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.form-group textarea {
  min-height: 140px;
  resize: vertical;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(0, 136, 255, 0.18);
}

.form-success {
  display: none;
  margin-top: 1.2rem;
  padding: 1rem 1.2rem;
  border-radius: 12px;
  background: rgba(45, 212, 191, 0.12);
  border: 1px solid rgba(45, 212, 191, 0.4);
  color: var(--text);
  font-size: 0.92rem;
  font-weight: 500;
}

.form-success.visible {
  display: block;
}

.contact-card h3 {
  font-size: 1.15rem;
  margin-bottom: 0.6rem;
}

.contact-card p {
  font-size: 0.93rem;
  color: var(--text-muted);
  margin-bottom: 1.2rem;
}

.contact-email {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-weight: 600;
  color: var(--accent);
}

.contact-email svg {
  width: 18px;
  height: 18px;
}

/* ---------- Legal Pages ---------- */
.legal-content {
  max-width: 760px;
  margin: 0 auto;
  padding-bottom: 4rem;
}

.legal-content h1 {
  font-size: clamp(2rem, 4vw, 2.8rem);
  letter-spacing: -0.025em;
  margin-bottom: 1.2rem;
}

.legal-content h2 {
  font-size: 1.3rem;
  margin: 2.2rem 0 0.7rem;
}

.legal-content h3 {
  font-size: 1.05rem;
  margin: 1.6rem 0 0.5rem;
}

.legal-content p {
  color: var(--text-muted);
  margin-bottom: 1rem;
}

.legal-content ul {
  list-style: disc;
  padding-left: 1.5rem;
  margin-bottom: 1rem;
  color: var(--text-muted);
}

.legal-content li {
  margin-bottom: 0.4rem;
}

.legal-content strong {
  color: var(--text);
}

/* Hinweis für nicht-deutsche Sprachen auf den Rechtsseiten */
.legal-en-note {
  margin: 1rem 0;
  padding: 0.9rem 1.2rem;
  border-radius: 12px;
  background: var(--bg-soft);
  border: 1px solid var(--border);
  font-size: 0.9rem;
  color: var(--text-muted);
}

/* Sprachabhängige Inhaltsblöcke (Umschaltung in main.js) */
[data-lang-block] {
  display: none;
}

[data-lang-block].lang-visible {
  display: block;
}

.back-link {
  display: inline-block;
  margin-top: 2.5rem;
  font-weight: 600;
  color: var(--accent);
}

/* ---------- Mobile Navigation ---------- */
.nav-burger {
  display: none;
  width: 38px;
  height: 38px;
  border-radius: 10px;
  border: 1px solid var(--border);
  background: var(--bg-soft);
  color: var(--text);
  place-items: center;
}

.nav-burger svg {
  width: 20px;
  height: 20px;
}

/* ---------- Responsive ---------- */
@media (max-width: 960px) {
  .feature-grid {
    grid-template-columns: repeat(2, 1fr);
  }

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

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

  .showcase-item {
    grid-template-columns: 1fr;
    gap: 2.5rem;
    text-align: center;
  }

  .showcase-item:nth-child(even) .showcase-media {
    order: 0;
  }

  .showcase-list {
    display: inline-block;
    text-align: left;
  }

  .support-form-wrap {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 720px) {
  .nav-links {
    position: fixed;
    top: 68px;
    left: 0;
    right: 0;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    background: var(--bg-elevated);
    border-bottom: 1px solid var(--border);
    padding: 0.6rem 1.2rem;
    display: none;
    box-shadow: var(--shadow-lg);
  }

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

  .nav-links a {
    padding: 0.85rem 0.4rem;
    border-bottom: 1px solid var(--border);
  }

  .nav-links a:last-child {
    border-bottom: none;
  }

  .nav-burger {
    display: grid;
  }

  .btn-nav,
  .appstore-badge-nav {
    display: none;
  }

  .hero {
    padding: 9rem 0 5rem;
  }

  section {
    padding: 4rem 0;
  }

  .feature-grid,
  .topic-grid {
    grid-template-columns: 1fr;
  }

  .footer-grid {
    grid-template-columns: 1fr;
    gap: 1.8rem;
  }

  .form-row {
    grid-template-columns: 1fr;
  }
}

/* ---------- Reduced Motion ---------- */
@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    transition: none !important;
    animation: none !important;
  }
}