.akku-calculator {
    --color-primary: #2f8f3e;
    --color-primary-foreground: #ffffff;
    --color-primary-soft: #e6f3e4;
    --color-ink: #0f2417;
    --color-muted-foreground: #5b6b60;
    --color-border: #e2ebe4;
    --color-card: #ffffff;
    --color-warn: #fff8ec;
    --color-warn-border: #f5d99a;
    --color-warn-foreground: #7a4a10;
    --gradient-primary: linear-gradient(135deg, #34a04a 0%, #1f7233 100%);
    --gradient-section: linear-gradient(180deg, #f4faf5 0%, #e9f4ea 100%);
    --shadow-card: 0 10px 30px -12px rgba(20, 60, 30, 0.15);
    --shadow-cta: 0 12px 24px -10px rgba(31, 114, 51, 0.5);
    --shadow-lift: 0 6px 18px -8px rgba(31, 114, 51, 0.35);
  }
  .akku-calculator,
  .akku-calculator * { box-sizing: border-box; }
  .akku-calculator { margin: 0; padding: 0; }
  .akku-calculator {
    font-family: 'DM Sans', system-ui, -apple-system, sans-serif;
    color: var(--color-ink);
    background: var(--gradient-section);
    min-height: 100vh;
    -webkit-font-smoothing: antialiased;
    line-height: 1.5;
  }
  .akku-calculator h1,
  .akku-calculator h2,
  .akku-calculator h3 { font-family: 'Montserrat', 'DM Sans', sans-serif; letter-spacing: -0.02em; }
  .akku-calculator button { font-family: inherit; cursor: pointer; }

  .akku-container { max-width: 42rem; margin: 0 auto; padding: 0 1rem; }
  header.akku-hero { padding: 2rem 1rem 1.5rem; text-align: center; }
  @media (min-width: 640px) { header.akku-hero { padding: 3.5rem 1rem 2.5rem; } }
  .akku-badge {
    display: inline-flex; align-items: center; gap: 0.5rem;
    background: rgba(255,255,255,0.7); backdrop-filter: blur(8px);
    border: 1px solid rgba(47,143,62,0.2);
    color: var(--color-primary);
    padding: 0.375rem 1rem;
    border-radius: 999px;
    font-size: 0.75rem; font-weight: 700; text-transform: uppercase; letter-spacing: 0.08em;
  }
  h1.akku-title {
    margin: 1rem 0 0; font-size: 1.875rem; font-weight: 700; line-height: 1.1;
  }
  @media (min-width: 640px) { h1.akku-title { font-size: 2.5rem; } }
  h1.akku-title .akku-accent { color: var(--color-primary); position: relative; display: inline-block; }
  h1.akku-title .akku-accent::after {
    content: ''; position: absolute; left: 0; right: 0; bottom: 4px; height: 12px;
    background: var(--color-primary-soft); border-radius: 999px; z-index: -1;
  }
  .akku-lead { max-width: 32rem; margin: 1rem auto 0; color: var(--color-muted-foreground); font-size: 1rem; }
  @media (min-width: 640px) { .akku-lead { font-size: 1.125rem; } }
  .akku-calculator main { padding: 0 1rem 6rem; }

  .akku-progress-row {
    display: flex; align-items: center; justify-content: space-between;
    font-size: 0.875rem; font-weight: 600; color: var(--color-muted-foreground);
    margin-bottom: 1rem;
  }
  .akku-reset-btn {
    display: inline-flex; align-items: center; gap: 0.375rem;
    padding: 0.375rem 0.75rem; border-radius: 999px; border: 0; background: transparent;
    color: var(--color-muted-foreground); font-size: 0.75rem; font-weight: 600;
    transition: all 0.2s;
  }
  .akku-reset-btn:hover { background: #fff; color: var(--color-primary); }

  .akku-progress-bar { height: 0.5rem; width: 100%; background: var(--color-primary-soft); border-radius: 999px; overflow: hidden; margin-bottom: 1.5rem; }
  .akku-progress-fill { height: 100%; background: var(--gradient-primary); border-radius: 999px; transition: width 0.5s ease-out; }

  .akku-card {
    background: var(--color-card);
    border: 1px solid var(--color-border);
    border-radius: 1.5rem;
    padding: 1.25rem;
    box-shadow: var(--shadow-card);
  }
  @media (min-width: 640px) { .akku-card { padding: 2rem; } }

  .akku-step-head { display: flex; align-items: flex-start; gap: 1rem; }
  .akku-step-icon {
    display: grid; place-items: center; flex-shrink: 0;
    width: 3.5rem; height: 3.5rem; border-radius: 1rem;
    background: var(--gradient-primary); color: #fff;
  }
  .akku-step-icon svg { width: 1.75rem; height: 1.75rem; }
  .akku-step-title { font-size: 1.25rem; font-weight: 700; margin: 0; line-height: 1.2; }
  @media (min-width: 640px) { .akku-step-title { font-size: 1.5rem; } }
  .akku-step-help { margin: 0.5rem 0 0; color: var(--color-muted-foreground); font-size: 0.875rem; }
  @media (min-width: 640px) { .akku-step-help { font-size: 1rem; } }

  .akku-options { display: grid; gap: 0.75rem; margin-top: 1.5rem; }
  @media (min-width: 640px) {
    .akku-options.akku-cols-2 { grid-template-columns: repeat(2, 1fr); }
    .akku-options.akku-cols-3 { grid-template-columns: repeat(3, 1fr); }
  }
  .akku-option {
    position: relative; display: flex; flex-direction: column; align-items: center; justify-content: center;
    gap: 0.25rem;
    min-height: 4rem; padding: 1rem;
    background: #fff; border: 2px solid var(--color-border); border-radius: 1rem;
    color: var(--color-ink); text-align: center;
    transition: all 0.2s;
  }
  .akku-option:hover { border-color: rgba(47,143,62,0.4); background: rgba(230,243,228,0.4); }
  .akku-option.akku-active { border-color: var(--color-primary); background: var(--color-primary-soft); color: var(--color-primary); box-shadow: var(--shadow-lift); }
  .akku-option .akku-lbl { font-size: 1rem; font-weight: 700; line-height: 1.2; }
  @media (min-width: 640px) { .akku-option .akku-lbl { font-size: 1.125rem; } }
  .akku-option .akku-sub { font-size: 0.75rem; color: var(--color-muted-foreground); line-height: 1.2; }
  .akku-option.akku-active .akku-sub { color: rgba(47,143,62,0.8); }
  .akku-option .akku-check { position: absolute; top: 0.5rem; right: 0.5rem; width: 1rem; height: 1rem; color: var(--color-primary); display: none; }
  .akku-option.akku-active .akku-check { display: block; }

  .akku-nav-row { margin-top: 2rem; display: grid; grid-template-columns: 1fr 1fr; gap: 0.75rem; }
  .akku-btn {
    display: inline-flex; align-items: center; justify-content: center; gap: 0.5rem;
    min-height: 3.5rem; padding: 0 1.25rem;
    border-radius: 1rem; border: 0; font-weight: 700; font-size: 1rem;
    transition: all 0.2s;
  }
  .akku-btn svg { width: 1.25rem; height: 1.25rem; }
  .akku-btn-secondary { background: #fff; border: 1px solid var(--color-border); color: var(--color-ink); font-weight: 600; }
  .akku-btn-secondary:hover:not(:disabled) { background: var(--color-primary-soft); }
  .akku-btn-secondary:disabled { opacity: 0.4; cursor: not-allowed; }
  .akku-btn-primary { background: var(--gradient-primary); color: #fff; box-shadow: var(--shadow-cta); }
  .akku-btn-primary:hover { transform: translateY(-2px); }

  .akku-disclaimer { text-align: center; color: var(--color-muted-foreground); font-size: 0.875rem; margin-top: 1.5rem; }

  /* Sliders */
  .akku-slider-card { border: 1px solid var(--color-border); border-radius: 1rem; padding: 1rem; background: #fff; }
  @media (min-width: 640px) { .akku-slider-card { padding: 1.25rem; } }
  .akku-slider-head { display: flex; align-items: center; gap: 0.75rem; }
  .akku-slider-icon {
    display: grid; place-items: center; width: 2.5rem; height: 2.5rem; border-radius: 0.75rem;
    background: var(--color-primary-soft); color: var(--color-primary); flex-shrink: 0;
  }
  .akku-slider-icon svg { width: 1.25rem; height: 1.25rem; }
  .akku-slider-label { font-size: 0.875rem; font-weight: 600; color: var(--color-muted-foreground); }
  .akku-slider-value { font-size: 1.125rem; font-weight: 700; font-variant-numeric: tabular-nums; }
  .akku-slider-help { font-size: 0.75rem; color: var(--color-muted-foreground); margin-top: 0.5rem; }
  .akku-calculator input[type=range] {
    -webkit-appearance: none; appearance: none;
    width: 100%; height: 0.75rem; margin-top: 0.75rem;
    border-radius: 999px; outline: none; cursor: pointer;
  }
  .akku-calculator input[type=range]::-webkit-slider-thumb {
    -webkit-appearance: none; appearance: none;
    width: 1.5rem; height: 1.5rem; border-radius: 50%;
    background: #fff; border: 3px solid var(--color-primary); box-shadow: var(--shadow-lift);
    cursor: pointer;
  }
  .akku-calculator input[type=range]::-moz-range-thumb {
    width: 1.5rem; height: 1.5rem; border-radius: 50%;
    background: #fff; border: 3px solid var(--color-primary); box-shadow: var(--shadow-lift); cursor: pointer;
  }
  .akku-stack { display: grid; gap: 0.75rem; margin-top: 1.5rem; }

  /* Result */
  .akku-kicker { font-size: 0.75rem; font-weight: 700; text-transform: uppercase; letter-spacing: 0.08em; color: var(--color-primary); }
  .akku-big-num { font-size: 3.75rem; font-weight: 700; line-height: 1; font-variant-numeric: tabular-nums; letter-spacing: -0.03em; }
  @media (min-width: 640px) { .akku-big-num { font-size: 4.5rem; } }
  .akku-big-unit { font-size: 1.5rem; font-weight: 700; color: var(--color-muted-foreground); }
  @media (min-width: 640px) { .akku-big-unit { font-size: 1.875rem; } }
  .akku-tier-badge {
    display: inline-flex; align-items: center; gap: 0.5rem;
    background: var(--color-primary-soft); color: var(--color-primary);
    padding: 0.375rem 0.75rem; border-radius: 999px;
    font-size: 0.875rem; font-weight: 700;
  }
  .akku-tier-badge svg { width: 1rem; height: 1rem; }
  .akku-summary-box {
    background: rgba(230,243,228,0.5); border: 1px solid var(--color-border); border-radius: 1rem;
    padding: 1rem;
  }
  @media (min-width: 640px) { .akku-summary-box { padding: 1.25rem; } }
  .akku-summary-box p { margin: 0; }
  .akku-summary-title { font-size: 1rem; font-weight: 700; color: var(--color-ink); }
  .akku-summary-text { color: var(--color-muted-foreground); font-size: 0.875rem; margin-top: 0.375rem; }
  @media (min-width: 640px) { .akku-summary-text { font-size: 1rem; } }

  .akku-stats { display: grid; grid-template-columns: repeat(2, 1fr); gap: 0.75rem; margin-top: 1rem; }
  .akku-stat { background: #fff; border: 1px solid var(--color-border); border-radius: 1rem; padding: 0.875rem; }
  @media (min-width: 640px) { .akku-stat { padding: 1rem; } }
  .akku-stat-value { font-size: 1.125rem; font-weight: 700; font-variant-numeric: tabular-nums; }
  @media (min-width: 640px) { .akku-stat-value { font-size: 1.25rem; } }
  .akku-stat-label { font-size: 0.75rem; font-weight: 500; color: var(--color-muted-foreground); margin-top: 0.25rem; }
  @media (min-width: 640px) { .akku-stat-label { font-size: 0.875rem; } }
  .akku-good { color: #059669; }
  .akku-mid { color: #d97706; }
  .akku-bad { color: #ea580c; }
  .akku-stat-value.akku-needs-refinement { font-size: 1rem; line-height: 1.25; }

  .akku-precision-note {
    margin-top: 1.5rem; padding: 1rem;
    background: #f4f8ff; border: 1px solid #cfdcf4; border-radius: 1rem;
    color: #344054; font-size: 0.875rem; line-height: 1.55;
  }
  .akku-precision-note-title { display: flex; align-items: center; gap: 0.5rem; color: #274c77; font-weight: 800; }
  .akku-precision-note-title svg { width: 1rem; height: 1rem; flex-shrink: 0; }
  .akku-precision-note p { margin: 0.5rem 0 0; }
  @media (min-width: 640px) {
    .akku-precision-note { padding: 1.125rem 1.25rem; font-size: 0.9375rem; }
  }

  .akku-reasons-head { display: flex; align-items: center; gap: 0.5rem; font-size: 0.875rem; font-weight: 700; margin-top: 1.5rem; }
  .akku-reasons-head svg { width: 1rem; height: 1rem; color: var(--color-primary); }
  .akku-reasons { list-style: none; padding: 0; margin: 0.75rem 0 0; display: grid; gap: 0.5rem; }
  .akku-reasons li { display: flex; gap: 0.625rem; font-size: 0.875rem; color: var(--color-muted-foreground); line-height: 1.5; }
  @media (min-width: 640px) { .akku-reasons li { font-size: 1rem; } }
  .akku-reasons li::before {
    content: ''; flex-shrink: 0; margin-top: 0.5rem; width: 0.375rem; height: 0.375rem; border-radius: 50%; background: var(--color-primary);
  }
  .akku-warn {
    margin-top: 1.5rem; margin-bottom: 1.5rem; display: flex; gap: 0.75rem; align-items: flex-start;
    background: var(--color-warn); border: 1px solid var(--color-warn-border);
    border-radius: 1rem; padding: 1rem; color: var(--color-warn-foreground);
    font-size: 0.875rem; line-height: 1.5;
  }
  @media (min-width: 640px) { .akku-warn { padding: 1.25rem; } }
  .akku-warn svg { width: 1.25rem; height: 1.25rem; flex-shrink: 0; margin-top: 0.125rem; }

  /* Contact gate */
  .akku-contact-intro { display: flex; align-items: flex-start; gap: 1rem; }
  .akku-contact-promise {
    margin-top: 1.5rem; padding: 1rem 1.125rem;
    background: rgba(230,243,228,0.5); border: 1px solid var(--color-border); border-radius: 1rem;
    color: var(--color-muted-foreground); font-size: 0.9375rem;
  }
  .akku-contact-promise p { margin: 0; color: var(--color-ink); font-weight: 700; }
  .akku-contact-promise ul { margin: 0.75rem 0 0; padding-left: 1.25rem; display: grid; gap: 0.375rem; }
  .akku-contact-form { display: grid; gap: 1rem; margin-top: 1.5rem; }
  .akku-form-group { display: grid; gap: 0.375rem; }
  .akku-form-group label { color: var(--color-ink); font-size: 0.875rem; font-weight: 700; }
  .akku-form-group input {
    width: 100%; min-height: 3.25rem; padding: 0.75rem 0.875rem;
    border: 1px solid var(--color-border); border-radius: 0.875rem;
    background: #fff; color: var(--color-ink); font: inherit; outline: none;
    transition: border-color 0.2s, box-shadow 0.2s;
  }
  .akku-form-group input:focus { border-color: var(--color-primary); box-shadow: 0 0 0 3px rgba(47,143,62,0.14); }
  .akku-field-error { display: none; color: #b42318; font-size: 0.8125rem; font-weight: 600; }
  .akku-form-group.akku-invalid input { border-color: #d92d20; box-shadow: 0 0 0 3px rgba(217,45,32,0.1); }
  .akku-invalid > .akku-field-error { display: block; }
  .akku-consent-wrap {
    display: grid; grid-template-columns: 1.25rem 1fr; column-gap: 0.625rem; align-items: start;
    padding: 0.875rem; border: 1px solid var(--color-border); border-radius: 0.875rem; background: #fff;
  }
  .akku-consent-wrap input { width: 1.125rem; height: 1.125rem; margin: 0.15rem 0 0; accent-color: var(--color-primary); }
  .akku-consent-wrap label { color: var(--color-muted-foreground); font-size: 0.8125rem; line-height: 1.5; }
  .akku-consent-wrap a { color: var(--color-primary); font-weight: 700; text-decoration: underline; }
  .akku-consent-wrap .akku-field-error { grid-column: 2; margin-top: 0.375rem; }
  .akku-consent-wrap.akku-invalid { border-color: #d92d20; background: #fff6f5; }
  .akku-form-note { margin: 0; color: var(--color-muted-foreground); font-size: 0.8125rem; line-height: 1.55; }
  .akku-form-alert {
    margin-top: 1rem; padding: 0.875rem 1rem; border: 1px solid #f5b5ad; border-radius: 0.875rem;
    background: #fff1f0; color: #912018; font-size: 0.875rem; font-weight: 700; line-height: 1.5;
  }
  .akku-honeypot { position: absolute !important; left: -10000px !important; width: 1px !important; height: 1px !important; overflow: hidden !important; }
  .akku-result-ref { margin-top: 0.375rem; color: var(--color-muted-foreground); font-size: 0.75rem; }
  .akku-btn:disabled { opacity: 0.65; cursor: wait; transform: none; }

  /* Icons - use inline SVG symbols */
  .akku-i { width: 100%; height: 100%; }

  /* screen switch */
  .akku-hidden { display: none !important; }