/* =========================================================
   KI-Newsletter — Dark Theme (fullstack.de Style)
   ahead GmbH | Akzentfarbe ahead-Orange #ff4800
   ========================================================= */

/* --- Reset & Base ---------------------------------------- */
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; background: #0a0a0a; }
body, h1, h2, h3, h4, h5, h6, p, ul, ol, figure, blockquote { margin: 0; }
ul, ol { padding: 0; list-style: none; }
img, picture, svg, video { display: block; max-width: 100%; height: auto; }
button, input, textarea, select { font: inherit; color: inherit; }
a { color: inherit; text-decoration: none; }

/* --- Design Tokens --------------------------------------- */
:root {
  /* Brand accent (ahead-Orange) */
  --accent:           #ff4800;
  --accent-hover:     #ff6a30;
  --accent-soft:      rgba(255, 72, 0, 0.12);
  --accent-glow:      rgba(255, 72, 0, 0.35);
  --accent-ring:      rgba(255, 72, 0, 0.30);

  /* Dark base palette */
  --bg:               #0a0a0a;        /* page background */
  --bg-elevated:      #141414;        /* cards / surfaces */
  --bg-subtle:        #1a1a1a;        /* hover states */
  --bg-deep:          #050505;        /* CTA bands / footer */
  --line:             rgba(255, 255, 255, 0.08);
  --line-strong:      rgba(255, 255, 255, 0.16);

  /* Text */
  --text:             #ffffff;
  --text-muted:       rgba(255, 255, 255, 0.65);
  --text-subtle:      rgba(255, 255, 255, 0.45);
  --text-faint:       rgba(255, 255, 255, 0.30);

  /* Typography */
  --font-display: "Instrument Serif", "Cormorant Garamond", "Times New Roman", Georgia, serif;
  --font-sans:    "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
  --font-mono:    "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, monospace;

  /* Type scale (fluid) */
  --fs-xs:   0.8125rem;
  --fs-sm:   0.9375rem;
  --fs-base: 1.0625rem;
  --fs-lg:   1.1875rem;
  --fs-xl:   1.375rem;
  --fs-2xl:  1.75rem;
  --fs-3xl:  clamp(1.875rem, 1.4rem + 1.8vw, 2.625rem);
  --fs-4xl:  clamp(2.25rem, 1.6rem + 2.6vw, 3.5rem);
  --fs-5xl:  clamp(2.75rem, 1.6rem + 4.2vw, 5rem);
  --fs-6xl:  clamp(3.5rem, 2.2rem + 5.5vw, 6.75rem);

  /* Spacing */
  --sp-1: 0.25rem;
  --sp-2: 0.5rem;
  --sp-3: 0.75rem;
  --sp-4: 1rem;
  --sp-5: 1.5rem;
  --sp-6: 2rem;
  --sp-7: 3rem;
  --sp-8: 4rem;
  --sp-9: 6rem;
  --sp-10: 8rem;

  /* Layout */
  --container:     min(1240px, 100% - 2.5rem);
  --container-md:  min(900px,  100% - 2.5rem);
  --container-sm:  min(680px,  100% - 2.5rem);

  /* Radii & shadows */
  --radius-sm:  6px;
  --radius:     12px;
  --radius-lg:  20px;
  --radius-xl:  28px;
  --radius-pill: 999px;

  --shadow-md: 0 8px 24px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 32px 64px -16px rgba(0, 0, 0, 0.6);
  --shadow-glow: 0 16px 48px -8px var(--accent-glow);

  --transition: 220ms cubic-bezier(0.4, 0.0, 0.2, 1);
}

/* --- Body ------------------------------------------------ */
body {
  font-family: var(--font-sans);
  font-size: var(--fs-base);
  line-height: 1.55;
  color: var(--text);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  font-feature-settings: "ss01", "cv11";
}

/* --- Typography ------------------------------------------ */
h1, h2, h3, h4 {
  font-family: var(--font-display);
  font-weight: 400;
  letter-spacing: -0.01em;
  line-height: 1.05;
  color: var(--text);
}
h1 { font-size: var(--fs-6xl); letter-spacing: -0.035em; line-height: 0.95; }
h2 { font-size: var(--fs-5xl); letter-spacing: -0.025em; line-height: 1.0; }
h3 { font-size: var(--fs-2xl); letter-spacing: -0.01em; line-height: 1.15; }
h4 { font-size: var(--fs-xl); line-height: 1.25; }

h1 em, h2 em, h3 em {
  font-style: italic;
  color: var(--accent);
  font-weight: 400;
}

.eyebrow {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.18em;
  color: var(--accent);
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
}
.eyebrow::before {
  content: "";
  width: 18px;
  height: 1px;
  background: var(--accent);
}

p { color: var(--text-muted); }
.lead {
  font-size: var(--fs-lg);
  line-height: 1.55;
  color: var(--text-muted);
  max-width: 56ch;
}

a.text-link {
  color: var(--accent);
  border-bottom: 1px solid var(--accent-ring);
  transition: border-color var(--transition);
}
a.text-link:hover { border-bottom-color: var(--accent); }

/* --- Layout ---------------------------------------------- */
.container     { width: var(--container);     margin-inline: auto; }
.container-md  { width: var(--container-md);  margin-inline: auto; }
.container-sm  { width: var(--container-sm);  margin-inline: auto; }

section { padding: var(--sp-9) 0; position: relative; }
@media (max-width: 720px) { section { padding: var(--sp-8) 0; } }

.section-divider {
  height: 1px;
  background: var(--line);
  margin: 0;
}

/* --- Header / Navigation --------------------------------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(10, 10, 10, 0.7);
  backdrop-filter: saturate(180%) blur(18px);
  -webkit-backdrop-filter: saturate(180%) blur(18px);
  border-bottom: 1px solid transparent;
  transition: border-color var(--transition), background var(--transition);
}
.site-header.scrolled {
  border-bottom-color: var(--line);
  background: rgba(10, 10, 10, 0.92);
}
.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--sp-4) 0;
  gap: var(--sp-5);
}
.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.625rem;
  font-family: var(--font-sans);
  font-weight: 600;
  font-size: 1.0625rem;
  letter-spacing: -0.015em;
  color: var(--text);
}
.brand-mark {
  width: 32px; height: 32px;
  border-radius: 8px;
  background: var(--accent);
  display: grid; place-items: center;
  color: #0a0a0a;
  font-family: var(--font-display);
  font-size: 1.15rem;
  line-height: 1;
  font-weight: 600;
}
.brand-mark span { display: inline-block; transform: translateY(1px); }

.nav-links {
  display: flex;
  align-items: center;
  gap: var(--sp-5);
  font-size: var(--fs-sm);
  color: var(--text-muted);
}
.nav-links a { transition: color var(--transition); }
.nav-links a:hover { color: var(--text); }
.nav-links a.is-active { color: var(--text); }

.nav-cta { display: inline-flex; }
@media (max-width: 880px) {
  .nav-links { display: none; }
}

/* --- Buttons --------------------------------------------- */
.btn {
  --btn-bg: var(--text);
  --btn-fg: var(--bg);
  --btn-border: transparent;
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.875rem 1.5rem;
  border-radius: var(--radius-pill);
  background: var(--btn-bg);
  color: var(--btn-fg);
  border: 1px solid var(--btn-border);
  font-size: var(--fs-sm);
  font-weight: 500;
  letter-spacing: -0.005em;
  cursor: pointer;
  transition: transform var(--transition), background var(--transition), color var(--transition), box-shadow var(--transition), border-color var(--transition);
  white-space: nowrap;
  text-decoration: none;
}
.btn:hover { transform: translateY(-1px); }
.btn .arrow { transition: transform var(--transition); }
.btn:hover .arrow { transform: translateX(3px); }

.btn-primary {
  --btn-bg: var(--accent);
  --btn-fg: #ffffff;
  box-shadow: 0 8px 24px -8px var(--accent-glow);
}
.btn-primary:hover {
  --btn-bg: var(--accent-hover);
  box-shadow: 0 16px 36px -8px var(--accent-glow);
}
.btn-light {
  --btn-bg: var(--text);
  --btn-fg: var(--bg);
}
.btn-light:hover { --btn-bg: rgba(255,255,255,0.92); }
.btn-ghost {
  --btn-bg: transparent;
  --btn-fg: var(--text);
  --btn-border: var(--line-strong);
}
.btn-ghost:hover {
  --btn-bg: var(--bg-elevated);
  --btn-border: rgba(255,255,255,0.32);
}

.btn-lg { padding: 1.125rem 1.875rem; font-size: var(--fs-base); }

/* --- Hero ------------------------------------------------- */
.hero {
  padding: var(--sp-9) 0 var(--sp-9);
  position: relative;
  overflow: hidden;
  background: var(--bg);
}
.hero::before {
  content: "";
  position: absolute;
  inset: -20% -20% auto auto;
  width: 75vw;
  height: 75vw;
  max-width: 900px;
  max-height: 900px;
  background: radial-gradient(closest-side, var(--accent-soft), transparent 70%);
  pointer-events: none;
  z-index: 0;
}
.hero::after {
  content: "";
  position: absolute;
  inset: auto 0 -50% 0;
  height: 60%;
  background: radial-gradient(ellipse at center bottom, rgba(255, 72, 0, 0.08), transparent 60%);
  pointer-events: none;
  z-index: 0;
}
.hero-inner {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: 1.15fr 1fr;
  gap: var(--sp-8);
  align-items: center;
}
@media (max-width: 960px) {
  .hero-inner { grid-template-columns: 1fr; gap: var(--sp-7); }
}
.hero h1 { margin-bottom: var(--sp-5); }
.hero .eyebrow { margin-bottom: var(--sp-5); }
.hero .lead { margin-bottom: var(--sp-6); font-size: var(--fs-xl); }
.hero-actions { display: flex; flex-wrap: wrap; gap: var(--sp-3); }
.hero-meta {
  margin-top: var(--sp-7);
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--sp-5);
  font-size: var(--fs-sm);
  color: var(--text-subtle);
}
.hero-meta strong { color: var(--text); font-weight: 600; }
.hero-meta > div { display: flex; align-items: center; gap: 0.5rem; }
.hero-meta .star { color: var(--accent); }

/* Form card (HubSpot embed wrapper) ---------------------- */
.form-card {
  background: var(--bg-elevated);
  border: 1px solid var(--line-strong);
  border-radius: var(--radius-xl);
  padding: var(--sp-6);
  position: relative;
  box-shadow: var(--shadow-lg);
}
.form-card::before {
  content: "";
  position: absolute;
  inset: -1px;
  border-radius: inherit;
  pointer-events: none;
  background: linear-gradient(135deg, var(--accent-soft) 0%, transparent 50%);
  opacity: 0.7;
  z-index: -1;
}
.form-card .eyebrow { margin-bottom: var(--sp-4); }
.form-card h3 { margin-bottom: var(--sp-3); font-size: var(--fs-2xl); }
.form-card > p { margin-bottom: var(--sp-5); font-size: var(--fs-sm); color: var(--text-muted); }

/* HubSpot iframe styling — leichtes Theming des Embeds */
.form-card .hs-form-frame {
  min-height: 200px;
}
.form-card .hs-form-frame iframe {
  width: 100% !important;
}
.form-card .form-foot {
  margin-top: var(--sp-4);
  font-size: 0.8125rem;
  color: var(--text-subtle);
}
.form-card .form-foot a { color: var(--text-muted); border-bottom: 1px solid var(--line-strong); }
.form-card .form-foot a:hover { color: var(--accent); border-color: var(--accent); }

/* --- Section heads --------------------------------------- */
.section-head {
  max-width: 760px;
  margin-bottom: var(--sp-8);
}
.section-head .eyebrow { margin-bottom: var(--sp-4); }
.section-head h2 { margin-bottom: var(--sp-4); }
.section-head p { font-size: var(--fs-lg); color: var(--text-muted); }
.section-head.center { margin-inline: auto; text-align: center; }
.section-head.center .eyebrow { justify-content: center; }

/* --- Feature grid (3-up cards) -------------------------- */
.feature-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--sp-5);
}
@media (max-width: 900px) { .feature-grid { grid-template-columns: 1fr; } }

.feature-card {
  background: var(--bg-elevated);
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  padding: var(--sp-6);
  display: flex;
  flex-direction: column;
  gap: var(--sp-3);
  transition: transform var(--transition), border-color var(--transition), background var(--transition);
  position: relative;
  overflow: hidden;
}
.feature-card::after {
  content: "";
  position: absolute;
  inset: auto auto 0 0;
  width: 100%;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--accent), transparent);
  opacity: 0;
  transition: opacity var(--transition);
}
.feature-card:hover {
  transform: translateY(-4px);
  border-color: var(--line-strong);
  background: var(--bg-subtle);
}
.feature-card:hover::after { opacity: 1; }
.feature-card .icon {
  width: 48px; height: 48px;
  border-radius: 12px;
  background: var(--accent-soft);
  display: grid; place-items: center;
  color: var(--accent);
  margin-bottom: var(--sp-3);
}
.feature-card h3 { font-size: var(--fs-xl); line-height: 1.25; color: var(--text); }
.feature-card p { font-size: var(--fs-sm); color: var(--text-muted); }
.feature-card a.more {
  margin-top: auto;
  font-family: var(--font-mono);
  font-size: var(--fs-xs);
  text-transform: uppercase;
  letter-spacing: 0.14em;
  color: var(--accent);
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding-top: var(--sp-4);
}
.feature-card a.more:hover { color: var(--accent-hover); }
.feature-card a.more span { transition: transform var(--transition); }
.feature-card a.more:hover span { transform: translateX(4px); }

/* --- Topics grid (audience cards) ----------------------- */
.topics-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--sp-5);
}
@media (max-width: 760px) { .topics-grid { grid-template-columns: 1fr; } }
.topic-card {
  background: var(--bg-elevated);
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  padding: var(--sp-6);
  position: relative;
  display: block;
  transition: transform var(--transition), border-color var(--transition), background var(--transition);
}
.topic-card:hover {
  transform: translateY(-3px);
  border-color: var(--accent);
  background: var(--bg-subtle);
}
.topic-card .pill {
  display: inline-block;
  padding: 4px 10px;
  border-radius: 999px;
  background: var(--accent-soft);
  color: var(--accent);
  font-family: var(--font-mono);
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.14em;
  margin-bottom: var(--sp-4);
  font-weight: 500;
}
.topic-card h3 { margin-bottom: var(--sp-3); font-size: var(--fs-xl); color: var(--text); }
.topic-card p { font-size: var(--fs-sm); color: var(--text-muted); }
.topic-card .arrow-link {
  display: inline-flex;
  margin-top: var(--sp-4);
  font-size: var(--fs-sm);
  color: var(--text);
  font-weight: 500;
  align-items: center;
  gap: 0.375rem;
}
.topic-card .arrow-link span { transition: transform var(--transition); }
.topic-card:hover .arrow-link { color: var(--accent); }
.topic-card:hover .arrow-link span { transform: translateX(4px); }

/* --- Issue rows (archive) ------------------------------- */
.issues {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--sp-3);
}
.issue-row {
  background: var(--bg-elevated);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: var(--sp-5) var(--sp-6);
  display: grid;
  grid-template-columns: 100px 1fr auto;
  gap: var(--sp-5);
  align-items: center;
  transition: border-color var(--transition), background var(--transition);
}
.issue-row:hover { border-color: var(--accent); background: var(--bg-subtle); }
.issue-num {
  font-family: var(--font-display);
  font-size: 2.75rem;
  line-height: 1;
  color: var(--accent);
  letter-spacing: -0.025em;
  font-style: italic;
}
.issue-row h3 { font-size: var(--fs-lg); margin-bottom: 0.25rem; line-height: 1.3; color: var(--text); }
.issue-row p { font-size: var(--fs-sm); margin: 0; color: var(--text-muted); }
@media (max-width: 720px) {
  .issue-row { grid-template-columns: 60px 1fr; }
  .issue-row .issue-cta { grid-column: 1 / -1; justify-self: start; }
  .issue-num { font-size: 2rem; }
}

/* --- FAQ -------------------------------------------------- */
.faq {
  display: grid;
  gap: var(--sp-3);
  max-width: 820px;
  margin-inline: auto;
}
.faq details {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--bg-elevated);
  padding: 0;
  transition: border-color var(--transition), background var(--transition);
}
.faq details[open] {
  border-color: var(--accent);
  background: var(--bg-subtle);
}
.faq summary {
  list-style: none;
  cursor: pointer;
  padding: 1.25rem 1.5rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: var(--sp-4);
  font-weight: 500;
  font-size: var(--fs-base);
  color: var(--text);
}
.faq summary::-webkit-details-marker { display: none; }
.faq summary .plus {
  flex-shrink: 0;
  width: 28px; height: 28px;
  border: 1px solid var(--line-strong);
  border-radius: 50%;
  display: grid; place-items: center;
  font-size: 16px;
  color: var(--text-muted);
  transition: transform var(--transition), background var(--transition), color var(--transition), border-color var(--transition);
}
.faq details[open] .plus {
  transform: rotate(45deg);
  background: var(--accent);
  color: #fff;
  border-color: var(--accent);
}
.faq .answer {
  padding: 0 1.5rem 1.5rem;
  color: var(--text-muted);
  font-size: var(--fs-base);
  line-height: 1.65;
}

/* --- CTA band -------------------------------------------- */
.cta-band {
  background: var(--bg-deep);
  border: 1px solid var(--line);
  color: var(--text);
  border-radius: var(--radius-xl);
  padding: var(--sp-9) var(--sp-7);
  text-align: center;
  position: relative;
  overflow: hidden;
}
.cta-band::before {
  content: "";
  position: absolute;
  inset: -50% -20% auto -20%;
  height: 130%;
  background: radial-gradient(ellipse at center, rgba(255, 72, 0, 0.20), transparent 55%);
  pointer-events: none;
}
.cta-band > * { position: relative; z-index: 1; }
.cta-band .eyebrow { color: var(--accent); justify-content: center; margin-bottom: var(--sp-4); }
.cta-band h2 { color: var(--text); margin-bottom: var(--sp-3); }
.cta-band p { color: var(--text-muted); max-width: 56ch; margin: 0 auto var(--sp-6); font-size: var(--fs-lg); }

/* --- Legal pages (Impressum, Datenschutz) --------------- */
.legal {
  max-width: 760px;
  margin-inline: auto;
}
.legal h1 { margin-bottom: var(--sp-5); font-size: var(--fs-5xl); }
.legal h2 {
  font-size: var(--fs-2xl);
  margin: var(--sp-7) 0 var(--sp-3);
  padding-top: var(--sp-5);
  border-top: 1px solid var(--line);
  color: var(--text);
}
.legal h3 { font-size: var(--fs-xl); margin: var(--sp-5) 0 var(--sp-2); color: var(--text); }
.legal p, .legal li { color: var(--text-muted); margin-bottom: 0.875rem; line-height: 1.7; font-size: var(--fs-base); }
.legal ul { padding-left: 1.25rem; list-style: disc; }
.legal a { color: var(--accent); text-decoration: underline; text-decoration-thickness: 1px; text-underline-offset: 3px; }
.legal strong { color: var(--text); font-weight: 600; }

/* --- Footer ---------------------------------------------- */
.site-footer {
  background: var(--bg-deep);
  color: var(--text);
  padding: var(--sp-8) 0 var(--sp-5);
  margin-top: var(--sp-9);
  border-top: 1px solid var(--line);
}
.site-footer .footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: var(--sp-7);
  padding-bottom: var(--sp-7);
  border-bottom: 1px solid var(--line);
}
@media (max-width: 760px) {
  .site-footer .footer-grid { grid-template-columns: 1fr 1fr; gap: var(--sp-5); }
}
.site-footer h4 {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  font-weight: 500;
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: 0.16em;
  margin-bottom: var(--sp-4);
}
.site-footer .brand { color: var(--text); margin-bottom: var(--sp-3); }
.site-footer .footer-tagline { color: var(--text-subtle); font-size: var(--fs-sm); max-width: 32ch; }
.site-footer ul { display: grid; gap: 0.625rem; }
.site-footer ul a {
  color: var(--text-muted);
  font-size: var(--fs-sm);
  transition: color var(--transition);
}
.site-footer ul a:hover { color: var(--accent); }
.footer-bottom {
  padding-top: var(--sp-4);
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: var(--sp-3);
  font-size: var(--fs-xs);
  color: var(--text-faint);
  font-family: var(--font-mono);
  letter-spacing: 0.05em;
}

/* --- Reveal animations (CSS only) ----------------------- */
@media (prefers-reduced-motion: no-preference) {
  .reveal {
    opacity: 0;
    transform: translateY(16px);
    animation: reveal-up 700ms cubic-bezier(0.2, 0.7, 0.2, 1) forwards;
  }
  .reveal.d1 { animation-delay: 90ms; }
  .reveal.d2 { animation-delay: 180ms; }
  .reveal.d3 { animation-delay: 270ms; }
  .reveal.d4 { animation-delay: 360ms; }
  .reveal.d5 { animation-delay: 450ms; }
  @keyframes reveal-up {
    to { opacity: 1; transform: translateY(0); }
  }
}

/* --- Utilities ------------------------------------------- */
.text-center { text-align: center; }
.mt-0 { margin-top: 0; } .mt-2 { margin-top: var(--sp-3); } .mt-4 { margin-top: var(--sp-5); } .mt-6 { margin-top: var(--sp-7); }
.mb-0 { margin-bottom: 0; }

/* Skip link for a11y */
.skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
  background: var(--accent);
  color: #fff;
  padding: 0.75rem 1rem;
  border-radius: 0 0 var(--radius) 0;
  z-index: 100;
}
.skip-link:focus { left: 0; }

/* Selection */
::selection { background: var(--accent); color: #fff; }

/* Scrollbar (dark theme) */
::-webkit-scrollbar { width: 10px; height: 10px; }
::-webkit-scrollbar-track { background: var(--bg); }
::-webkit-scrollbar-thumb { background: var(--bg-elevated); border-radius: 10px; border: 2px solid var(--bg); }
::-webkit-scrollbar-thumb:hover { background: var(--bg-subtle); }

/* Print */
@media print {
  .site-header, .site-footer, .nav-cta, .cta-band { display: none; }
  body { background: white; color: black; }
}