/* ============================================================
   Gebäudeakte Pro – styles.css
   Professional, minimal administrative style
   ============================================================ */

/* ---------- Design Tokens ---------- */
:root {
  --color-navy: #1a2b4a;
  --color-navy-dark: #111e36;
  --color-navy-light: #2d4270;
  --color-anthracite: #2d3748;
  --color-text: #1f2937;
  --color-text-muted: #6b7280;
  --color-text-faint: #9ca3af;
  --color-bg: #ffffff;
  --color-bg-alt: #f8f9fa;
  --color-border: #e5e7eb;
  --color-border-strong: #d1d5db;
  --color-accent: #1a2b4a;

  --font-sans: 'Inter', system-ui, -apple-system, sans-serif;

  --radius-sm: 4px;
  --radius-md: 6px;

  --max-w: 1120px;
  --section-py: 80px;
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.7;
  color: var(--color-text);
  background: var(--color-bg);
  -webkit-font-smoothing: antialiased;
}

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

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

ul {
  list-style: none;
}

/* ---------- Utilities ---------- */
.container {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 32px;
}

.section {
  padding: var(--section-py) 0;
}

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

/* ---------- Buttons ---------- */
.btn {
  display: inline-block;
  font-family: var(--font-sans);
  font-size: 15px;
  font-weight: 500;
  padding: 12px 24px;
  border-radius: var(--radius-md);
  cursor: pointer;
  border: none;
  letter-spacing: 0.01em;
}

.btn-primary {
  background: var(--color-navy);
  color: #ffffff;
  border: 1.5px solid var(--color-navy);
}

.btn-primary:hover {
  background: var(--color-navy-dark);
  border-color: var(--color-navy-dark);
}

.btn-sm {
  padding: 8px 16px;
  font-size: 14px;
}

.link-secondary {
  font-size: 15px;
  font-weight: 500;
  color: var(--color-text-muted);
  border-bottom: 1px solid var(--color-border-strong);
  padding-bottom: 1px;
}

.link-secondary:hover {
  color: var(--color-text);
}

/* ---------- Navigation ---------- */
.nav-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255, 255, 255, 0.97);
  border-bottom: 1px solid var(--color-border);
}

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

.logo {
  font-size: 15px;
  font-weight: 700;
  color: var(--color-navy);
  letter-spacing: -0.01em;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 28px;
}

.nav-links a:not(.btn) {
  font-size: 14px;
  color: var(--color-text-muted);
  font-weight: 500;
}

.nav-links a:not(.btn):hover {
  color: var(--color-text);
}

/* ---------- Hero ---------- */
.hero {
  padding: 80px 0 72px;
  border-bottom: 1px solid var(--color-border);
}

.hero-inner {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 64px;
  align-items: center;
}

.hero-claim {
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--color-text-muted);
  margin-bottom: 20px;
}

.hero-text h1 {
  font-size: clamp(28px, 3.5vw, 40px);
  font-weight: 700;
  line-height: 1.2;
  color: var(--color-navy-dark);
  letter-spacing: -0.02em;
  margin-bottom: 20px;
}

.hero-sub {
  font-size: 17px;
  line-height: 1.65;
  color: var(--color-text-muted);
  margin-bottom: 36px;
  max-width: 480px;
}

.hero-actions {
  display: flex;
  align-items: center;
  gap: 24px;
  flex-wrap: wrap;
}

.hero-mockup img {
  width: 100%;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  box-shadow: 0 8px 32px rgba(26, 43, 74, 0.08), 0 2px 8px rgba(0, 0, 0, 0.04);
}

.hero-centered {
  grid-template-columns: 1fr;
  max-width: 700px;
}

.hero-centered .hero-text h1 {
  font-size: clamp(28px, 4vw, 44px);
}

.hero-centered .hero-sub {
  max-width: 100%;
}

/* ---------- Problem Section ---------- */
.problem-list {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0;
  margin-top: 40px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  overflow: hidden;
}

.problem-item {
  display: flex;
  gap: 16px;
  padding: 28px 28px;
  border-right: 1px solid var(--color-border);
  border-bottom: 1px solid var(--color-border);
}

.problem-item:nth-child(2),
.problem-item:nth-child(4) {
  border-right: none;
}

.problem-item:nth-child(3),
.problem-item:nth-child(4) {
  border-bottom: none;
}

.problem-icon {
  flex-shrink: 0;
  margin-top: 2px;
  opacity: 0.6;
}

.problem-item strong {
  display: block;
  font-size: 15px;
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: 6px;
}

.problem-item p {
  font-size: 14px;
  color: var(--color-text-muted);
  line-height: 1.6;
}

/* ---------- Solution Section ---------- */
.section h2 {
  font-size: clamp(22px, 3vw, 30px);
  font-weight: 700;
  color: var(--color-navy-dark);
  letter-spacing: -0.02em;
  line-height: 1.25;
  margin-bottom: 16px;
}

.solution-inner {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 64px;
  align-items: start;
}

.solution-text p {
  font-size: 16px;
  color: var(--color-text-muted);
  line-height: 1.7;
  margin-top: 8px;
}

.solution-diagram {
  display: flex;
  flex-direction: column;
  gap: 0;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  overflow: hidden;
  font-size: 14px;
}

.diagram-building {
  background: var(--color-navy);
  color: #fff;
  padding: 14px 20px;
  font-weight: 600;
  font-size: 13px;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

.diagram-rooms {
  display: flex;
  flex-direction: column;
}

.diagram-room {
  padding: 16px 20px;
  border-top: 1px solid var(--color-border);
  display: flex;
  flex-direction: column;
  gap: 3px;
}

.diagram-room:hover {
  background: var(--color-bg-alt);
}

.room-name {
  font-weight: 600;
  color: var(--color-text);
  font-size: 14px;
}

.room-circuits {
  font-size: 13px;
  color: var(--color-text-muted);
  font-family: 'Inter', monospace;
}

.room-note {
  font-size: 12px;
  color: var(--color-text-faint);
  font-style: italic;
}

/* ---------- Features Section ---------- */
.features-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 0;
  margin-top: 40px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  overflow: hidden;
}

.feature-item {
  padding: 32px 28px;
  border-right: 1px solid var(--color-border);
}

.feature-item:last-child {
  border-right: none;
}

.feature-number {
  display: block;
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.1em;
  color: var(--color-text-faint);
  margin-bottom: 14px;
  font-variant-numeric: tabular-nums;
}

.feature-item h3 {
  font-size: 15px;
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: 10px;
  line-height: 1.35;
}

.feature-item p {
  font-size: 14px;
  color: var(--color-text-muted);
  line-height: 1.65;
}

/* ---------- Waitlist Section ---------- */
.waitlist-box {
  max-width: 600px;
  margin: 0 auto;
  text-align: center;
}

.waitlist-sub {
  font-size: 17px;
  color: var(--color-text-muted);
  margin-top: 12px;
  margin-bottom: 36px;
}

.waitlist-form {
  text-align: left;
}

.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  margin-bottom: 20px;
}

.form-group {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.form-group label {
  font-size: 13px;
  font-weight: 500;
  color: var(--color-text);
}

.optional {
  font-weight: 400;
  color: var(--color-text-faint);
  font-size: 12px;
}

.required {
  color: var(--color-navy);
}

.form-group input {
  font-family: var(--font-sans);
  font-size: 15px;
  padding: 10px 14px;
  border: 1.5px solid var(--color-border-strong);
  border-radius: var(--radius-sm);
  color: var(--color-text);
  background: #fff;
  outline: none;
  width: 100%;
}

.form-group input:focus {
  border-color: var(--color-navy);
}

.form-group input::placeholder {
  color: var(--color-text-faint);
}

.waitlist-form .btn-primary {
  width: 100%;
  text-align: center;
  padding: 13px;
  font-size: 15px;
  font-weight: 600;
}

.form-note {
  text-align: center;
  margin-top: 14px;
  font-size: 13px;
  color: var(--color-text-faint);
}

.form-success {
  padding: 24px;
  background: var(--color-bg-alt);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  text-align: center;
  color: var(--color-text-muted);
  font-size: 15px;
}

/* ---------- Footer ---------- */
.footer {
  border-top: 1px solid var(--color-border);
  padding: 28px 0;
  background: var(--color-bg);
}

.footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  flex-wrap: wrap;
}

.footer-logo {
  font-size: 13px;
  font-weight: 700;
  color: var(--color-navy);
}

.footer-nav {
  display: flex;
  gap: 24px;
}

.footer-nav a {
  font-size: 13px;
  color: var(--color-text-muted);
}

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

.footer-copy {
  font-size: 13px;
  color: var(--color-text-faint);
}

/* ---------- Responsive ---------- */
@media (max-width: 900px) {
  :root {
    --section-py: 56px;
  }

  .hero-inner {
    grid-template-columns: 1fr;
    gap: 40px;
  }

  .hero-mockup {
    order: -1;
  }

  .solution-inner {
    grid-template-columns: 1fr;
    gap: 40px;
  }

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

  .feature-item:nth-child(2) {
    border-right: none;
  }

  .feature-item:nth-child(1),
  .feature-item:nth-child(2) {
    border-bottom: 1px solid var(--color-border);
  }

  .problem-list {
    grid-template-columns: 1fr;
  }

  .problem-item {
    border-right: none !important;
  }

  .problem-item:nth-child(3) {
    border-bottom: 1px solid var(--color-border) !important;
  }
}

@media (max-width: 600px) {
  .container {
    padding: 0 20px;
  }

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

  .feature-item {
    border-right: none;
    border-bottom: 1px solid var(--color-border);
  }

  .feature-item:last-child {
    border-bottom: none;
  }

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

  .footer-inner {
    flex-direction: column;
    align-items: flex-start;
    gap: 12px;
  }

  .nav-links a:not(.btn) {
    display: none;
  }
}