/* =====================================================
   Stripe-inspired Design System for Rechnungsgenerator
   ===================================================== */

/* CSS Variables */
:root {
  --color-primary: #533afd;
  --color-primary-hover: #4434d4;
  --color-heading: #061b31;
  --color-body: #64748d;
  --color-label: #273951;
  --color-bg: #ffffff;
  --color-surface: #f6f9fc;
  --color-border: #e5edf5;
  --color-border-focus: #533afd;
  --color-success: #15be53;
  --color-error: #e25950;
  --color-warning: #f5a623;
  --shadow-card: 0 15px 35px rgba(23, 23, 23, 0.08);
  --shadow-elevated: rgba(50, 50, 93, 0.25) 0px 30px 45px -30px, rgba(0, 0, 0, 0.1) 0px 18px 36px -18px;
  --font-primary: 'Source Sans 3', system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --radius-sm: 4px;
  --radius-md: 6px;
  --radius-lg: 8px;
  --spacing-xs: 4px;
  --spacing-sm: 8px;
  --spacing-md: 16px;
  --spacing-lg: 24px;
  --spacing-xl: 32px;
  --spacing-2xl: 48px;
  --transition-fast: 150ms ease;
  --transition-base: 200ms ease;
}

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

html {
  -webkit-text-size-adjust: 100%;
  -moz-tab-size: 4;
  tab-size: 4;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-primary);
  font-size: 16px;
  line-height: 1.5;
  color: var(--color-body);
  background-color: var(--color-surface);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

img, picture, video, canvas, svg {
  display: block;
  max-width: 100%;
}

input, button, textarea, select {
  font: inherit;
  color: inherit;
}

p, h1, h2, h3, h4, h5, h6 {
  overflow-wrap: break-word;
}

/* Typografie */
h1, h2, h3, h4, h5, h6 {
  color: var(--color-heading);
  font-weight: 600;
  line-height: 1.25;
  letter-spacing: 0;
}

h1 { font-size: 28px; }
h2 { font-size: 22px; }
h3 { font-size: 18px; }
h4 { font-size: 16px; }

p {
  margin-bottom: var(--spacing-md);
}

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

a:hover {
  color: var(--color-primary-hover);
  text-decoration: underline;
}

small {
  font-size: 14px;
  line-height: 1.4;
}

/* Layout Utilities */
.container {
  width: 100%;
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
  padding-left: var(--spacing-md);
  padding-right: var(--spacing-md);
}

@media (min-width: 768px) {
  .container {
    padding-left: var(--spacing-xl);
    padding-right: var(--spacing-xl);
  }
}

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

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-sm);
  font-family: var(--font-primary);
  font-size: 15px;
  font-weight: 600;
  line-height: 1;
  padding: 10px 16px;
  min-height: 44px;
  border: 1px solid transparent;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: background-color var(--transition-fast), border-color var(--transition-fast), box-shadow var(--transition-fast), transform var(--transition-fast);
  text-decoration: none;
  white-space: nowrap;
  touch-action: manipulation;
  user-select: none;
}

.btn:focus-visible {
  outline: 2px solid var(--color-border-focus);
  outline-offset: 2px;
}

.btn:active {
  transform: translateY(1px);
}

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

.btn--primary:hover {
  background-color: var(--color-primary-hover);
  border-color: var(--color-primary-hover);
  color: #ffffff;
  text-decoration: none;
}

.btn--ghost {
  background-color: transparent;
  color: var(--color-primary);
  border-color: var(--color-border);
}

.btn--ghost:hover {
  background-color: var(--color-surface);
  border-color: var(--color-primary);
  color: var(--color-primary-hover);
  text-decoration: none;
}

.btn--success {
  background-color: var(--color-success);
  color: #ffffff;
  border-color: var(--color-success);
}

.btn--success:hover {
  filter: brightness(0.95);
  text-decoration: none;
}

.btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  pointer-events: none;
}

.btn[aria-disabled="true"] {
  cursor: pointer;
}

.btn--small {
  font-size: 14px;
  padding: 6px 12px;
  min-height: 36px;
}

.btn--hero {
  min-height: 48px;
  padding: 14px 20px;
}

.btn--attention[aria-disabled="true"] {
  box-shadow: 0 0 0 3px rgba(226, 89, 80, 0.12);
}

.btn--full {
  width: 100%;
}

/* Inputs & Forms */
.form-group {
  margin-bottom: var(--spacing-lg);
}

.form-label {
  display: block;
  font-size: 14px;
  font-weight: 600;
  color: var(--color-label);
  margin-bottom: var(--spacing-sm);
}

.form-label .required {
  color: var(--color-error);
  margin-left: 2px;
}

.form-hint {
  font-size: 13px;
  color: var(--color-body);
  margin-top: var(--spacing-xs);
}

.form-input,
.form-select,
.form-textarea {
  display: block;
  width: 100%;
  font-family: var(--font-primary);
  font-size: 15px;
  font-weight: 400;
  color: var(--color-heading);
  background-color: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 10px 12px;
  min-height: 44px;
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
  outline: none;
}

.form-textarea {
  min-height: 88px;
  resize: vertical;
}

.form-input::placeholder,
.form-textarea::placeholder {
  color: #9aa5b8;
}

.form-input:focus,
.form-select:focus,
.form-textarea:focus {
  border-color: var(--color-border-focus);
  box-shadow: 0 0 0 3px rgba(83, 58, 253, 0.12);
}

.form-input[aria-invalid="true"],
.form-select[aria-invalid="true"],
.form-textarea[aria-invalid="true"] {
  border-color: var(--color-error);
  background-color: #fffafa;
}

.form-input[aria-invalid="true"]:focus,
.form-select[aria-invalid="true"]:focus,
.form-textarea[aria-invalid="true"]:focus {
  box-shadow: 0 0 0 3px rgba(226, 89, 80, 0.12);
}

.form-select {
  appearance: none;
  background-image: url("data:image/svg+xml,%3csvg xmlns='http://www.w3.org/2000/svg' fill='none' viewBox='0 0 20 20'%3e%3cpath stroke='%2364748d' stroke-linecap='round' stroke-linejoin='round' stroke-width='1.5' d='M6 8l4 4 4-4'/%3e%3c/svg%3e");
  background-position: right 10px center;
  background-repeat: no-repeat;
  background-size: 20px;
  padding-right: 40px;
}

/* Cards */
.card {
  background-color: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-card);
  padding: var(--spacing-lg);
}

@media (min-width: 768px) {
  .card {
    padding: var(--spacing-xl);
  }
}

.card--flat {
  box-shadow: none;
}

/* Radio Cards */
.radio-card {
  position: relative;
  display: flex;
  align-items: flex-start;
  gap: var(--spacing-md);
  padding: var(--spacing-md);
  background-color: var(--color-bg);
  border: 2px solid var(--color-border);
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.radio-card:hover {
  border-color: #c8d4e4;
}

.radio-card__input {
  position: absolute;
  opacity: 0;
  width: 0;
  height: 0;
}

.radio-card__indicator {
  flex-shrink: 0;
  width: 22px;
  height: 22px;
  border: 2px solid var(--color-border);
  border-radius: 50%;
  margin-top: 2px;
  transition: border-color var(--transition-fast), background-color var(--transition-fast);
  display: flex;
  align-items: center;
  justify-content: center;
}

.radio-card__indicator::after {
  content: '';
  width: 10px;
  height: 10px;
  background-color: var(--color-primary);
  border-radius: 50%;
  transform: scale(0);
  transition: transform var(--transition-fast);
}

.radio-card__content {
  flex: 1;
  display: flex;
  min-width: 0;
  flex-direction: column;
  gap: 2px;
}

.radio-card__title {
  display: block;
  font-size: 15px;
  font-weight: 600;
  color: var(--color-heading);
}

.radio-card__desc {
  display: block;
  font-size: 13px;
  color: var(--color-body);
  line-height: 1.4;
}

.radio-card__input:checked + .radio-card__indicator {
  border-color: var(--color-primary);
}

.radio-card__input:checked + .radio-card__indicator::after {
  transform: scale(1);
}

.radio-card__input:focus-visible + .radio-card__indicator {
  outline: 2px solid var(--color-border-focus);
  outline-offset: 2px;
}

.radio-card__input:checked ~ .radio-card__content .radio-card__title {
  color: var(--color-primary);
}

.radio-card:has(.radio-card__input:checked) {
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(83, 58, 253, 0.08);
}

/* Tooltip */
.tooltip {
  position: relative;
  display: inline-block;
  cursor: help;
}

.tooltip__icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 18px;
  height: 18px;
  font-size: 12px;
  font-weight: 600;
  color: var(--color-primary);
  background-color: rgba(83, 58, 253, 0.08);
  border-radius: 50%;
  margin-left: var(--spacing-xs);
}

.tooltip__text {
  visibility: hidden;
  opacity: 0;
  position: absolute;
  bottom: calc(100% + 8px);
  left: 50%;
  transform: translateX(-50%);
  width: max-content;
  max-width: 260px;
  background-color: var(--color-heading);
  color: #ffffff;
  font-size: 13px;
  font-weight: 400;
  line-height: 1.4;
  padding: 8px 12px;
  border-radius: var(--radius-sm);
  box-shadow: var(--shadow-elevated);
  transition: opacity var(--transition-fast), visibility var(--transition-fast);
  z-index: 100;
  pointer-events: none;
}

.tooltip__text::after {
  content: '';
  position: absolute;
  top: 100%;
  left: 50%;
  transform: translateX(-50%);
  border-width: 5px;
  border-style: solid;
  border-color: var(--color-heading) transparent transparent transparent;
}

.tooltip:hover .tooltip__text,
.tooltip:focus-within .tooltip__text {
  visibility: visible;
  opacity: 1;
}

/* Banner */
.banner {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-md);
  border-radius: var(--radius-md);
  font-size: 14px;
  line-height: 1.4;
}

.banner--info {
  background-color: rgba(83, 58, 253, 0.06);
  color: var(--color-primary);
  border: 1px solid rgba(83, 58, 253, 0.15);
}

.banner--success {
  background-color: rgba(21, 190, 83, 0.08);
  color: var(--color-success);
  border: 1px solid rgba(21, 190, 83, 0.2);
}

.banner--warning {
  background-color: rgba(245, 166, 35, 0.08);
  color: #b37a0e;
  border: 1px solid rgba(245, 166, 35, 0.2);
}

/* Spacing Utilities */
.mt-0 { margin-top: 0; }
.mt-1 { margin-top: var(--spacing-xs); }
.mt-2 { margin-top: var(--spacing-sm); }
.mt-3 { margin-top: var(--spacing-md); }
.mt-4 { margin-top: var(--spacing-lg); }
.mt-5 { margin-top: var(--spacing-xl); }

.mb-0 { margin-bottom: 0; }
.mb-1 { margin-bottom: var(--spacing-xs); }
.mb-2 { margin-bottom: var(--spacing-sm); }
.mb-3 { margin-bottom: var(--spacing-md); }
.mb-4 { margin-bottom: var(--spacing-lg); }
.mb-5 { margin-bottom: var(--spacing-xl); }

/* Grid */
.grid-2 {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--spacing-md);
}

@media (min-width: 768px) {
  .grid-2 {
    grid-template-columns: 1fr 1fr;
  }
}

/* Animations */
@keyframes fadeIn {
  from { opacity: 0; transform: translateY(8px); }
  to { opacity: 1; transform: translateY(0); }
}

.animate-fade-in {
  animation: fadeIn 250ms ease forwards;
}

/* Landing Page */
.landing-header,
.landing-footer {
  background-color: var(--color-bg);
}

.landing-container {
  max-width: 1120px;
}

.landing-nav,
.landing-footer__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--spacing-md);
}

.landing-nav {
  min-height: 72px;
}

.landing-brand {
  color: var(--color-heading);
  font-size: 18px;
  font-weight: 600;
}

.landing-main {
  background-color: var(--color-bg);
}

.landing-hero {
  background: linear-gradient(180deg, #ffffff 0%, #f6f9fc 100%);
  border-top: 1px solid var(--color-border);
  border-bottom: 1px solid var(--color-border);
}

.landing-hero__inner {
  padding-top: var(--spacing-lg);
  padding-bottom: var(--spacing-2xl);
}

.breadcrumb {
  font-size: 14px;
  margin-bottom: var(--spacing-xl);
}

.landing-hero__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--spacing-xl);
  align-items: center;
}

.landing-kicker {
  color: var(--color-primary);
  font-size: 14px;
  font-weight: 600;
  margin-bottom: var(--spacing-sm);
}

.landing-hero h1 {
  max-width: 760px;
  font-size: 38px;
  line-height: 1.08;
  margin-bottom: var(--spacing-lg);
}

.landing-hero__copy {
  max-width: 680px;
  color: var(--color-label);
  font-size: 18px;
  margin-bottom: var(--spacing-xl);
}

.landing-hero__actions {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: var(--spacing-md);
}

.landing-proof {
  color: var(--color-body);
  font-size: 15px;
}

.landing-proof strong {
  color: var(--color-heading);
  font-weight: 600;
}

.fact-box,
.landing-card {
  background-color: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-card);
  padding: var(--spacing-lg);
}

.fact-box {
  border-top: 4px solid var(--color-primary);
  width: 100%;
}

.invoice-preview {
  display: flex;
  justify-content: center;
  padding: var(--spacing-md);
  max-width: 600px;
}

.fact-box h2,
.landing-card h3,
.type-list h3,
.how-list h3 {
  font-size: 18px;
  margin-bottom: var(--spacing-sm);
}

.fact-box p,
.landing-card p,
.type-list p,
.how-list p,
.landing-cta p {
  margin-bottom: 0;
}

.fact-box ul {
  display: grid;
  gap: var(--spacing-sm);
  margin-top: var(--spacing-md);
  padding-left: var(--spacing-lg);
}

.sample-invoice {
  width: min(100%, 380px);
  color: var(--color-label);
  background-color: #ffffff;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  box-shadow: 0 18px 36px rgba(6, 27, 49, 0.12);
  padding: 28px;
  font-size: 13px;
  line-height: 1.5;
}

.sample-invoice strong {
  color: var(--color-heading);
  font-weight: 700;
}

.sample-invoice p {
  margin: 4px 0 0;
}

.sample-invoice__header,
.sample-invoice__addresses,
.sample-invoice__table > div,
.sample-invoice__totals > div {
  display: flex;
  justify-content: space-between;
  gap: var(--spacing-md);
}

.sample-invoice__header {
  align-items: flex-start;
  padding-bottom: 20px;
  border-bottom: 1px solid var(--color-border);
}

.sample-invoice__header strong {
  display: block;
  font-size: 22px;
  letter-spacing: 0.04em;
}

.sample-invoice__header > span {
  min-width: 88px;
  text-align: right;
}

.sample-invoice__header span,
.sample-invoice__addresses span,
.sample-invoice__table span,
.sample-invoice__totals span {
  color: var(--color-body);
}

.sample-invoice__addresses {
  margin-top: 20px;
  gap: 20px;
}

.sample-invoice__addresses > div {
  min-width: 0;
  flex: 1;
}

.sample-invoice__addresses span {
  display: block;
  margin-bottom: 4px;
  font-size: 13px;
  font-weight: 700;
}

.sample-invoice__addresses strong {
  display: block;
  font-size: 14px;
}

.sample-invoice__table {
  margin-top: 20px;
  overflow: hidden;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
}

.sample-invoice__table > div {
  align-items: center;
  padding: 10px 12px;
}

.sample-invoice__table > div:first-child {
  background-color: var(--color-surface);
  min-height: 38px;
  font-size: 13px;
  font-weight: 700;
}

.sample-invoice__totals {
  display: grid;
  gap: 8px;
  margin-top: 16px;
  margin-left: auto;
  max-width: 190px;
}

.sample-invoice__totals > div {
  align-items: baseline;
}

.sample-invoice__totals strong {
  min-width: 74px;
  text-align: right;
}

.sample-invoice__totals > div:last-child {
  padding-top: 8px;
  border-top: 1px solid var(--color-border);
  font-size: 14px;
}

.landing-section {
  padding: var(--spacing-2xl) 0;
}

.landing-section--soft {
  background-color: var(--color-surface);
}

.section-heading {
  max-width: 720px;
  margin-bottom: var(--spacing-xl);
}

.section-heading h2,
.landing-cta h2 {
  font-size: 28px;
}

.feature-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--spacing-md);
}

.landing-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  margin-bottom: var(--spacing-md);
  color: var(--color-primary);
}

.landing-icon svg {
  width: 24px;
  height: 24px;
  flex: 0 0 auto;
}

.type-list {
  display: grid;
  gap: var(--spacing-md);
}

.type-list > div {
  padding: var(--spacing-lg);
  background-color: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
}

.how-list {
  display: grid;
  gap: var(--spacing-md);
  list-style: none;
}

.how-list li {
  display: flex;
  gap: var(--spacing-md);
  padding: var(--spacing-lg);
  background-color: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
}

.how-list li > span {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  flex: 0 0 36px;
  width: 36px;
  height: 36px;
  color: var(--color-primary);
  background-color: rgba(83, 58, 253, 0.08);
  border-radius: 50%;
  font-weight: 700;
}

.faq-list {
  display: grid;
  gap: var(--spacing-sm);
}

.faq-list details {
  background-color: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--spacing-md) var(--spacing-lg);
}

.faq-list summary {
  color: var(--color-heading);
  cursor: pointer;
  font-weight: 600;
}

.faq-list p {
  margin-top: var(--spacing-md);
  margin-bottom: 0;
}

.landing-cta {
  padding: var(--spacing-2xl) 0;
  color: #ffffff;
  background-color: var(--color-heading);
}

.landing-cta h2,
.landing-cta p {
  color: #ffffff;
}

.landing-cta p {
  max-width: 620px;
  margin-top: var(--spacing-sm);
  margin-bottom: var(--spacing-lg);
}

.landing-footer {
  border-top: 1px solid var(--color-border);
}

.landing-footer__inner {
  flex-wrap: wrap;
  padding-top: var(--spacing-lg);
  padding-bottom: var(--spacing-lg);
}

.landing-footer p {
  margin-bottom: 0;
}

.landing-footer nav {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-md);
}

.landing-footer__note {
  flex: 0 0 100%;
  font-size: 13px;
}

.legal-page {
  background-color: var(--color-bg);
  border-top: 1px solid var(--color-border);
  padding: var(--spacing-xl) 0 var(--spacing-2xl);
}

.legal-container {
  max-width: 760px;
}

.legal-back {
  display: inline-flex;
  margin-bottom: var(--spacing-lg);
  font-weight: 600;
}

.legal-container h1 {
  margin-bottom: var(--spacing-xl);
}

.legal-container section {
  padding: var(--spacing-lg) 0;
  border-top: 1px solid var(--color-border);
}

.legal-container h2 {
  margin-bottom: var(--spacing-md);
  font-size: 28px;
}

.legal-container h3 {
  margin-top: var(--spacing-lg);
  margin-bottom: var(--spacing-sm);
  font-size: 20px;
}

.legal-container p,
.legal-container li {
  color: var(--color-text);
  line-height: 1.7;
}

.legal-container ul {
  margin-top: 0;
  margin-bottom: var(--spacing-md);
  padding-left: 1.2rem;
}

@media (min-width: 720px) {
  .landing-hero h1 {
    font-size: 56px;
  }

  .landing-hero__grid {
    grid-template-columns: minmax(0, 1fr) minmax(380px, 0.8fr);
  }

  .landing-hero__actions {
    flex-direction: row;
    align-items: center;
  }

  .feature-grid {
    grid-template-columns: repeat(4, 1fr);
  }

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

@media (max-width: 719px) {
  .landing-nav {
    min-height: 64px;
  }

  .landing-hero h1 {
    font-size: 34px;
  }

  .landing-card,
  .fact-box,
  .type-list > div,
  .how-list li {
    padding: var(--spacing-md);
  }
}