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

    :root {
      --sky:      #3ba7de;
      --sky-mid:  #1f7fbb;
      --navy:     #001d4d;
      --navy-mid: #07316f;
      --reed:     #76871e;
      --reed-mid: #667519;
      --soft-blue:#eef8fd;
      --soft-green:#f4f7ea;
      --border:   #d7e7ef;
      --text:     #001d4d;
      --muted:    #4c5a70;
      --warn-bg:  #fff7e6;
      --warn-bdr: #d89000;

      --font-head: 'Inter', Georgia, serif;
      --font-body: 'Inter', system-ui, sans-serif;

      --radius-lg: 24px;
      --radius-md: 18px;
      --radius-sm: 14px;
      --radius-pill: 999px;

      --shadow-card: 0 12px 32px rgba(0,29,77,0.10);
      --shadow-hero: 0 16px 42px rgba(0,29,77,0.18);
    }

    html { scroll-behavior: smooth; }

    body {
      font-family: var(--font-body);
      color: var(--text);
      background: #f0f6fb;
      min-height: 100vh;
      line-height: 1.6;
      -webkit-font-smoothing: antialiased;
    }

    /* ─── PAGE WRAPPER ─── */
    .page-wrapper {
      max-width: 1100px;
      margin: 0 auto;
      padding: clamp(24px, 5vw, 48px) clamp(16px, 4vw, 24px);
    }

    /* ─── LOGO BOX ─── */
    .logo-box {
      background: #0059aa;
      border: 6px solid #fff;
      border-radius: 28px;
      padding: clamp(20px, 4vw, 32px);
      margin-bottom: 24px;
      box-shadow: var(--shadow-hero);
      display: flex;
      align-items: center;
      justify-content: center;
      animation: fadeUp 0.55s ease both;
    }

    .logo-box svg {
      display: block;
      width: min(100%, 480px);
      height: auto;
    }

    /* ─── HERO ─── */
    .hero {
      background: linear-gradient(140deg, var(--navy) 0%, var(--navy-mid) 60%, #0d4480 100%);
      color: #fff;
      border-radius: var(--radius-lg);
      padding: clamp(24px, 5vw, 40px);
      margin-bottom: 28px;
      box-shadow: var(--shadow-hero);
      position: relative;
      overflow: hidden;
      animation: fadeUp 0.6s 0.1s ease both;
    }

    .hero::before {
      content: '';
      position: absolute;
      inset: 0;
      background:
        radial-gradient(ellipse 60% 60% at 90% -10%, rgba(59,167,222,0.18) 0%, transparent 70%),
        radial-gradient(ellipse 40% 40% at -10% 110%, rgba(0,89,170,0.25) 0%, transparent 70%);
      pointer-events: none;
    }

    .hero__eyebrow {
      font-family: var(--font-body);
      font-size: 0.78rem;
      font-weight: 900;
      letter-spacing: 0.1em;
      text-transform: uppercase;
      color: var(--sky);
      margin-bottom: 12px;
    }

    .hero h1 {
      font-family: var(--font-head);
      font-size: clamp(2rem, 4.5vw, 3.2rem);
      line-height: 1.06;
      margin-bottom: 14px;
      position: relative;
    }

    .hero p {
      font-size: clamp(0.97rem, 1.5vw, 1.08rem);
      max-width: 700px;
      line-height: 1.65;
      color: rgba(255,255,255,0.85);
      position: relative;
    }

    .hero p strong { color: #fff; }

    /* ─── TABS ─── */
    .tab-nav {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 12px;
      margin-bottom: 0;
      animation: fadeUp 0.6s 0.15s ease both;
    }

    .tab-nav__btn {
      background: #fff;
      border: 2px solid var(--border);
      color: var(--navy);
      border-radius: var(--radius-md);
      padding: 14px 12px;
      font-family: var(--font-body);
      font-size: 0.95rem;
      font-weight: 700;
      cursor: pointer;
      transition: all 0.2s;
      text-align: center;
    }

    .tab-nav__btn:hover,
    .tab-nav__btn.is-active {
      background: var(--sky);
      border-color: var(--sky);
      color: #fff;
      transform: translateY(-2px);
      box-shadow: 0 8px 22px rgba(59,167,222,0.28);
    }

    @media (max-width: 600px) {
      .tab-nav { grid-template-columns: 1fr; }
    }

    /* ─── CALCULATOR ─── */
    .calc-wrapper {
      margin: 28px 0 34px;
      animation: fadeUp 0.6s 0.2s ease both;
    }

    .calc-shell {
      background: linear-gradient(135deg, var(--sky), var(--sky-mid));
      border-radius: var(--radius-lg);
      padding: clamp(22px, 4vw, 36px);
      box-shadow: 0 16px 40px rgba(59,167,222,0.24);
    }

    .calc-shell__header {
      display: flex;
      flex-wrap: wrap;
      align-items: flex-start;
      justify-content: space-between;
      gap: 16px;
      margin-bottom: 18px;
    }

    .calc-shell__eyebrow {
      font-size: 0.78rem;
      font-weight: 900;
      letter-spacing: 0.1em;
      text-transform: uppercase;
      color: rgba(255,255,255,0.85);
      margin-bottom: 8px;
    }

    .calc-shell h2 {
      font-family: var(--font-head);
      font-size: clamp(1.5rem, 3vw, 2.1rem);
      color: #fff;
      line-height: 1.1;
    }

    .calc-shell__badge {
      background: rgba(255,255,255,0.16);
      border: 1px solid rgba(255,255,255,0.22);
      border-radius: var(--radius-md);
      padding: 11px 16px;
      font-weight: 900;
      font-size: 0.95rem;
      color: #fff;
      white-space: nowrap;
      backdrop-filter: blur(4px);
    }

    .calc-shell__desc {
      color: rgba(255,255,255,0.88);
      line-height: 1.6;
      margin-bottom: 22px;
      font-size: 0.98rem;
    }

    .calc-body {
      background: #fff;
      border-radius: var(--radius-md);
      padding: clamp(18px, 4vw, 28px);
    }

    .calc-mode-note {
      background: var(--soft-green);
      border-left: 5px solid var(--reed);
      border-radius: var(--radius-sm);
      padding: 12px 16px;
      font-size: 0.92rem;
      line-height: 1.5;
      margin-bottom: 20px;
      color: var(--text);
    }

    .calc-saltwater-extra { display: none; margin-bottom: 18px; }
    .calc-saltwater-extra.is-visible { display: block; }

    .calc-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 18px;
      margin-bottom: 20px;
    }

    @media (max-width: 600px) {
      .calc-grid { grid-template-columns: 1fr; }
    }

    .calc-field { display: flex; flex-direction: column; gap: 6px; }

    .calc-field label {
      font-weight: 800;
      font-size: 0.92rem;
      color: var(--navy);
    }

    .calc-field small {
      font-size: 0.83rem;
      color: var(--muted);
      line-height: 1.4;
    }

    .calc-field input,
    .calc-field select {
      width: 100%;
      border: 2px solid var(--border);
      border-radius: var(--radius-sm);
      padding: 13px 14px;
      font-family: var(--font-body);
      font-size: 1rem;
      color: var(--navy);
      background: #fff;
      transition: border-color 0.18s, box-shadow 0.18s;
    }

    .calc-field input:focus,
    .calc-field select:focus {
      outline: none;
      border-color: var(--sky);
      box-shadow: 0 0 0 4px rgba(59,167,222,0.14);
    }

    .volume-helper-btn {
      margin-top: 10px;
      width: 100%;
      border: 2px solid var(--reed);
      background: var(--soft-green);
      color: var(--reed);
      border-radius: var(--radius-sm);
      padding: 11px 14px;
      font-family: var(--font-body);
      font-weight: 900;
      font-size: 0.88rem;
      cursor: pointer;
      text-align: left;
      transition: all 0.18s;
      line-height: 1.4;
    }

    .volume-helper-btn:hover {
      background: var(--reed);
      color: #fff;
    }

    .volume-helper-panel {
      display: none;
      margin-top: 12px;
      background: #f8fbfd;
      border: 1px solid var(--border);
      border-radius: var(--radius-md);
      padding: 18px;
    }

    .volume-helper-panel.is-visible { display: block; }

    .volume-helper-result {
      margin-top: 14px;
      background: var(--soft-blue);
      border-radius: var(--radius-sm);
      padding: 12px 14px;
      font-weight: 800;
      font-size: 0.9rem;
      color: var(--navy);
    }

    .calc-results {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 12px;
      margin-bottom: 18px;
    }

    @media (max-width: 600px) {
      .calc-results { grid-template-columns: 1fr; }
    }

    .calc-card {
      background: var(--soft-blue);
      border-radius: var(--radius-md);
      padding: 16px 18px;
      border-top: 5px solid var(--sky);
    }

    .calc-card__label {
      font-size: 0.82rem;
      font-weight: 700;
      color: var(--muted);
    }

    .calc-card__value {
      display: block;
      font-family: var(--font-head);
      font-size: 1.6rem;
      color: var(--navy);
      margin-top: 4px;
      line-height: 1.1;
    }

    .calc-buy-btn {
      display: inline-flex;
      align-items: center;
      gap: 8px;
      margin-top: 10px;
      background: var(--reed);
      color: #fff;
      text-decoration: none;
      border-radius: var(--radius-pill);
      padding: 10px 16px;
      font-weight: 900;
      font-size: 0.88rem;
      transition: all 0.18s;
      box-shadow: 0 6px 16px rgba(118,135,30,0.26);
    }

    .calc-buy-btn:hover {
      background: var(--reed-mid);
      transform: translateY(-1px);
    }

    .calc-advice {
      background: var(--soft-green);
      border-left: 5px solid var(--reed);
      border-radius: var(--radius-sm);
      padding: 14px 16px;
      font-size: 0.92rem;
      line-height: 1.55;
      color: var(--navy);
    }

    .calc-reef-warning {
      margin-top: 14px;
      background: var(--warn-bg);
      border-left: 5px solid var(--warn-bdr);
      border-radius: var(--radius-sm);
      padding: 14px 16px;
      font-size: 0.92rem;
      line-height: 1.55;
    }

    /* ─── PANELS ─── */
    .panel {
      display: none;
      background: #fff;
      border: 1px solid var(--border);
      border-radius: var(--radius-lg);
      padding: clamp(22px, 5vw, 36px);
      box-shadow: var(--shadow-card);
      animation: panelIn 0.3s ease both;
    }

    .panel.is-active { display: block; }

    @keyframes panelIn {
      from { opacity: 0; transform: translateY(8px); }
      to   { opacity: 1; transform: translateY(0); }
    }

    .panel h2 {
      font-family: var(--font-head);
      font-size: clamp(1.6rem, 3vw, 2.2rem);
      margin-bottom: 22px;
      color: var(--navy);
    }

    /* ─── STEPS ─── */
    .steps {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 18px;
      margin-bottom: 24px;
    }

    @media (max-width: 700px) {
      .steps { grid-template-columns: 1fr; }
    }

    .step {
      background: var(--soft-blue);
      border-radius: var(--radius-md);
      padding: 20px;
      border-top: 5px solid var(--sky);
      position: relative;
      display: flex;
      flex-direction: column;
    }

    .step__num {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      width: 36px;
      height: 36px;
      border-radius: var(--radius-pill);
      background: var(--navy);
      color: #fff;
      font-weight: 900;
      font-size: 1rem;
      margin-bottom: 12px;
    }

    .step h3 {
      font-family: var(--font-head);
      font-size: 1.2rem;
      margin-bottom: 8px;
      color: var(--navy);
    }

    .step p {
      font-size: 0.93rem;
      line-height: 1.6;
      color: var(--muted);
      padding-bottom: 1rem;
    }
 
    .step__pack.p1, .step__pack.p2, .step__pack.p3 {
        background-size: contain;
        background-repeat: no-repeat;
        background-position: center;
        height: 10rem; 
        margin-top: auto;
    }
    .step__pack.p3 {
        background-image: url('../assets/Settle.svg');
    }

    
     .step__pack.p1  {
        background-image: url('../assets/Mix2.svg');
    }
    .step__pack.p2  {
        background-image: url('../assets/Apply2.svg');
    }
    .step__pack.pond.p1  {
        background-image: url('../assets/Mix1.svg');
    }
    .step__pack.pond.p2  {
        background-image: url('../assets/Apply1.svg');
    }
    /* ─── BADGES ─── */
    .badge-row {
      display: flex;
      flex-wrap: wrap;
      gap: 10px;
      margin: 20px 0;
    }

    .badge {
      display: inline-flex;
      align-items: center;
      gap: 8px;
      background: var(--soft-green);
      color: var(--reed);
      border: 1px solid rgba(118,135,30,0.2);
      border-radius: var(--radius-pill);
      padding: 8px 14px;
      font-weight: 800;
      font-size: 0.88rem;
    }

    /* ─── NOTE / WARNING ─── */
    .note {
      background: var(--soft-green);
      border-left: 5px solid var(--reed);
      border-radius: var(--radius-sm);
      padding: 14px 18px;
      margin: 18px 0;
      font-size: 0.93rem;
      line-height: 1.6;
    }

    .warning {
      background: var(--warn-bg);
      border-left: 5px solid var(--warn-bdr);
      border-radius: var(--radius-sm);
      padding: 14px 18px;
      margin: 18px 0;
      font-size: 0.93rem;
      line-height: 1.6;
    }

    /* ─── FAQ ─── */
    .faq {
      margin-top: 28px;
      border-top: 1px solid var(--border);
      padding-top: 18px;
    }

    .faq h3 {
      font-family: var(--font-head);
      font-size: 1.4rem;
      margin-bottom: 14px;
    }

    .faq details {
      border-bottom: 1px solid var(--border);
      padding: 14px 0;
    }

    .faq details p,
    .faq details ol,
    .faq details ul {
      margin-top: 10px;
      font-size: 0.93rem;
      line-height: 1.65;
      color: var(--muted);
    }

    .faq details ol,
    .faq details ul {
      padding-left: 1.4rem;
    }

    .faq details li { margin-bottom: 4px; }

    .faq summary {
      cursor: pointer;
      font-weight: 800;
      font-size: 0.97rem;
      color: var(--navy);
      list-style: none;
      display: flex;
      align-items: center;
      justify-content: space-between;
      gap: 12px;
    }

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

    .faq summary::after {
      content: '+';
      flex-shrink: 0;
      width: 26px;
      height: 26px;
      border-radius: var(--radius-pill);
      background: var(--soft-blue);
      display: inline-flex;
      align-items: center;
      justify-content: center;
      font-size: 1.2rem;
      color: var(--sky);
      font-weight: 700;
      transition: transform 0.2s;
    }

    .faq details[open] summary::after {
      content: '−';
      transform: rotate(180deg);
    }

    .faq__subhead {
      font-family: var(--font-head);
      font-size: 1.25rem;
      margin: 24px 0 10px;
      color: var(--navy);
    }

    /* ─── FOOTER ─── */
    .site-footer {
      background: var(--navy);
      color: rgba(255,255,255,0.65);
      text-align: center;
      padding: 28px 24px;
      font-size: 0.85rem;
      margin-top: 48px;
    }

    .site-footer a { color: var(--sky); text-decoration: none; }
    .site-footer a:hover { text-decoration: underline; }

    /* ─── ANIMATIONS ─── */
    @keyframes fadeUp {
      from { opacity: 0; transform: translateY(18px); }
      to   { opacity: 1; transform: translateY(0); }
    }