:root{
    --bg: #04120b;
    --bg-2: #1a1c1f;
    --wood: #6b4a30;
    --wood-dark: #503522;
    --logo-color: #ffce54;
    --board: #0f2018;
    --board-line: rgba(220,250,230,0.10);
    --chalk: #eef0f2;
    --chalk-dim: rgba(238,240,242,0.74);
    --chalk-faint: rgba(238,240,242,0.44);
    --accent: #3ddc97;
    --accent-dim: rgba(61,220,151,0.16);
    --accent-2: #ff8fa3;
    --accent-2-dim: rgba(255,143,163,0.16);
    --accent-3: #7fd8c4;
    --key-num: #202226;
    --key-func: #2c2f34;
    --key-op: #27292e;
    --key-border: rgba(238,240,242,0.14);
    --radius: 10px;
    --mono: 'JetBrains Mono', ui-monospace, Menlo, Consolas, monospace;
    --hand: 'Caveat', cursive;
  }

  /* ---------- TEMA CLARO (azul e branco) ---------- */
  :root[data-theme="light"]{
    --bg: #eef4fc;
    --bg-2: #ffffff;
    --wood: #c9a876;
    --wood-dark: #a9875a;
    --logo-color: #c98a12;
    --board: #17253d;
    --board-line: rgba(230,240,255,0.09);
    --chalk: #eaf2fb;
    --chalk-dim: rgba(234,242,251,0.7);
    --chalk-faint: rgba(234,242,251,0.42);
    --accent: #2f6fed;
    --accent-dim: rgba(47,111,237,0.14);
    --accent-2: #d1425f;
    --accent-2-dim: rgba(209,66,95,0.12);
    --accent-3: #1f9ac2;
    --key-num: #ffffff;
    --key-func: #e3edfb;
    --key-op: #e9f1fd;
    --key-border: rgba(20,45,90,0.14);
    --text-strong: #10233f;
  }

  :root[data-theme="light"] body{
    color: #10233f;
  }

  :root[data-theme="light"] .site-header h1{ color: #10233f; }
  :root[data-theme="light"] .tagline{ color: #3b5a86; }
  :root[data-theme="light"] .tab{ color: #3b5a86; }
  :root[data-theme="light"] .tab-note{ color: #6d89ac; }
  :root[data-theme="light"] .display-expr{ color: #6d89ac; }
  :root[data-theme="light"] .display-result:not(.err){ color: #10233f; }
  :root[data-theme="light"] .key{ color: #10233f; }
  :root[data-theme="light"] .key.func{ color: #3b5a86; }
  :root[data-theme="light"] .key.clear{ color: var(--accent-2); }
  :root[data-theme="light"] .key.equals{ color: #f4f9ff; }
  :root[data-theme="light"] .formula-solve{ color: #f4f9ff; }
  :root[data-theme="light"] .formula-btn{ color: #10233f; }
  :root[data-theme="light"] .formula-field label{ color: #3b5a86; }
  :root[data-theme="light"] .formula-field input{ color: #10233f; }
  :root[data-theme="light"] .board-sub{ color: rgba(234,242,251,0.55); }
  :root[data-theme="light"] .site-footer{ color: #6d89ac; }
  :root[data-theme="light"] .site-footer a{ color: var(--accent); }
  :root[data-theme="light"] .rules{ }

  /* Textos sobre fundos claros (painel de fórmulas, painel de foto, tabs) */
  :root[data-theme="light"] .formula-btn .fdesc{ color: #6d89ac; }
  :root[data-theme="light"] .formula-back{ color: #3b5a86; }
  :root[data-theme="light"] .formula-form-desc{ color: #6d89ac; }
  :root[data-theme="light"] .photo-intro p{ color: #3b5a86; }
  :root[data-theme="light"] .photo-warning{ color: #6d89ac !important; }
  :root[data-theme="light"] .photo-btn{ color: #f4f9ff; }
  :root[data-theme="light"] .photo-btn-ghost{ color: #3b5a86; }
  :root[data-theme="light"] .photo-loading{ color: #3b5a86; }
  :root[data-theme="light"] .photo-result label{ color: #3b5a86; }
  :root[data-theme="light"] .photo-result input{ color: #10233f; }
  :root[data-theme="light"] .study-link{ color: #3b5a86; }

  :root[data-theme="light"] body{
    background:
      radial-gradient(ellipse at 20% -10%, rgba(47,111,237,0.07), transparent 55%),
      radial-gradient(ellipse at 100% 10%, rgba(31,154,194,0.06), transparent 45%),
      var(--bg);
  }

  *{ box-sizing: border-box; }
  *,*::before,*::after{ min-width: 0; }

  html{ -webkit-text-size-adjust: 100%; }

  html,body{
    margin:0;
    padding:0;
    background: var(--bg);
    color: var(--chalk);
    font-family: var(--mono);
    -webkit-font-smoothing: antialiased;
    overflow-x: hidden;
    width: 100%;
  }

  body{
    background:
      radial-gradient(ellipse at 20% -10%, rgba(61,220,151,0.06), transparent 55%),
      radial-gradient(ellipse at 100% 10%, rgba(127,216,196,0.05), transparent 45%),
      var(--bg);
    min-height: 100vh;
  }

  a{ color: var(--accent); }

  button{ font: inherit; }

  .page{
    max-width: 1180px;
    margin: 0 auto;
    padding: 24px 20px 60px;
    width: 100%;
  }

  .site-header{
    text-align: center;
    margin-bottom: 26px;
    position: relative;
  }

  .theme-toggle{
    position: absolute;
    top: 2px;
    right: 6px;
    appearance: none;
    border: 1px solid var(--key-border);
    background: var(--key-func);
    color: var(--accent);
    width: 40px;
    height: 40px;
    border-radius: 50%;
    font-size: 1.1rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: border-color 0.15s ease, transform 0.15s ease;
    -webkit-tap-highlight-color: transparent;
  }
  .theme-toggle:hover{ border-color: color-mix(in srgb, var(--accent) 50%, transparent); transform: scale(1.05); }
  .theme-toggle:active{ transform: scale(0.94); }

  .site-header h1{
    font-family: var(--hand);
    font-weight: 700;
    font-size: clamp(2.1rem, 8vw, 3.6rem);
    margin: 0 0 6px;
    letter-spacing: 0.5px;
    line-height: 1;
  }

  .site-header h1 span{ color: var(--logo-color); }

  .site-logo-inline{
    width: 38px;
    height: 38px;
    vertical-align: middle;
    margin-right: 10px;
    object-fit: contain;
    position: relative;
    top: -3px;
  }

  .tagline{
    font-size: 0.9rem;
    color: var(--chalk-dim);
    margin: 0;
    max-width: 46ch;
    margin-inline: auto;
    padding: 0 6px;
  }

  .layout{
    display: grid;
    grid-template-columns: 360px 1fr;
    gap: 26px;
    align-items: start;
  }

  /* ---------- CALCULATOR ---------- */

  .calculator{
    background: linear-gradient(180deg, #3a3d42, #232529);
    border: 1px solid rgba(246,243,234,0.10);
    border-radius: 18px;
    padding: 16px;
    box-shadow: 0 24px 50px rgba(0,0,0,0.55), inset 0 1px 0 rgba(255,255,255,0.04);
  }

  .display{
    background: var(--bg-2);
    border-radius: 12px;
    padding: 18px 16px 14px;
    margin-bottom: 14px;
    text-align: right;
    min-height: 92px;
    display: flex;
    flex-direction: column;
    justify-content: flex-end;
    gap: 4px;
    border: 1px solid rgba(244,241,230,0.06);
  }

  .display-expr{
    font-size: 0.95rem;
    color: var(--chalk-faint);
    min-height: 1.2em;
    overflow-x: auto;
    white-space: nowrap;
    scrollbar-width: none;
  }
  .display-expr::-webkit-scrollbar{ display:none; }

  .display-result{
    font-size: clamp(1.7rem, 6vw, 2.3rem);
    font-weight: 600;
    letter-spacing: 0.5px;
    overflow-x: auto;
    white-space: nowrap;
    scrollbar-width: none;
  }
  .display-result::-webkit-scrollbar{ display:none; }
  .display-result.err{ color: var(--accent-2); font-size: 1.4rem; }

  /* ---------- TABS ---------- */

  .tabbar{
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 6px;
    margin-bottom: 12px;
    background: var(--bg-2);
    border-radius: 10px;
    padding: 4px;
    border: 1px solid rgba(244,241,230,0.06);
  }

  .tab{
    appearance: none;
    border: none;
    background: transparent;
    color: var(--chalk-dim);
    padding: 10px 2px;
    border-radius: 8px;
    font-family: var(--mono);
    font-size: 0.72rem;
    font-weight: 600;
    cursor: pointer;
    white-space: nowrap;
    -webkit-tap-highlight-color: transparent;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 3px;
  }

  .tab i{ font-size: 1rem; }

  .tab.active{
    background: var(--key-func);
    color: var(--accent);
    box-shadow: inset 0 0 0 1.5px color-mix(in srgb, var(--accent) 45%, transparent), 0 2px 10px color-mix(in srgb, var(--accent) 12%, transparent);
  }

  .tab-note{
    font-family: var(--hand);
    font-size: 1.05rem;
    color: var(--chalk-faint);
    margin: 10px 4px 0;
    text-align: center;
  }

  .keys{
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 7px;
  }

  .key{
    appearance: none;
    border: 1px solid var(--key-border);
    background: var(--key-num);
    color: var(--chalk);
    font-family: var(--mono);
    font-size: 1.05rem;
    font-weight: 500;
    padding: 14px 0;
    min-height: 48px;
    border-radius: 10px;
    cursor: pointer;
    transition: transform 0.06s ease, background 0.15s ease, border-color 0.15s ease;
    -webkit-tap-highlight-color: transparent;
  }
  .key:active{ transform: scale(0.94); }

  .key.func{ background: var(--key-func); color: var(--chalk-dim); font-size: 0.95rem; }
  .key.op{ background: var(--key-op); color: var(--accent); font-size: 1.1rem; }
  .key.const{ background: var(--key-op); color: var(--accent-3); font-size: 1.05rem; }
  .key.clear{ background: var(--key-func); color: var(--accent-2); }
  .key.equals{
    background: var(--accent);
    color: #062015;
    font-weight: 700;
    border-color: transparent;
  }
  .key:hover{ border-color: rgba(244,241,230,0.28); }
  .key.equals:hover{ filter: brightness(1.05); }
  .key.op:hover{ border-color: color-mix(in srgb, var(--accent) 50%, transparent); }
  .key.const:hover{ border-color: rgba(127,216,196,0.5); }
  .key.clear:hover{ border-color: rgba(255,143,163,0.5); }

  .key.wide{ grid-column: span 1; }

  /* ---------- FORMULAS PANEL ---------- */

  .formula-grid{
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 8px;
  }
  .formula-grid[hidden]{ display: none; }

  .formula-btn{
    appearance: none;
    text-align: left;
    border: 1px solid var(--key-border);
    background: var(--key-func);
    color: var(--chalk);
    border-radius: 10px;
    padding: 10px 11px;
    cursor: pointer;
    -webkit-tap-highlight-color: transparent;
    transition: border-color 0.15s ease;
  }
  .formula-btn:hover{ border-color: color-mix(in srgb, var(--accent) 40%, transparent); }
  .formula-btn .fname{
    display:block;
    font-weight: 700;
    font-size: 0.82rem;
    color: var(--accent);
    margin-bottom: 3px;
  }
  .formula-btn .fdesc{
    display:block;
    font-size: 0.72rem;
    color: var(--chalk-faint);
    line-height: 1.3;
  }

  .formula-form{
    background: var(--bg-2);
    border: 1px solid rgba(244,241,230,0.08);
    border-radius: 12px;
    padding: 14px;
  }

  .formula-form-head{
    display:flex;
    align-items:center;
    justify-content: space-between;
    gap: 8px;
    margin-bottom: 10px;
  }

  .formula-form-title{
    font-family: var(--hand);
    font-size: 1.3rem;
    color: var(--accent);
    margin: 0;
  }

  .formula-back{
    appearance:none;
    border: 1px solid var(--key-border);
    background: var(--key-func);
    color: var(--chalk-dim);
    border-radius: 8px;
    padding: 6px 10px;
    font-size: 0.75rem;
    cursor: pointer;
    -webkit-tap-highlight-color: transparent;
    flex-shrink: 0;
  }

  .formula-form-desc{
    font-size: 0.78rem;
    color: var(--chalk-faint);
    margin: 0 0 12px;
    line-height: 1.4;
  }

  .formula-fields{
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 10px;
    margin-bottom: 12px;
  }

  .formula-fields.single{ grid-template-columns: 1fr; }

  .formula-field label{
    display:block;
    font-size: 0.72rem;
    color: var(--chalk-dim);
    margin-bottom: 4px;
  }

  .formula-field input{
    width: 100%;
    background: var(--bg);
    border: 1px solid var(--key-border);
    color: var(--chalk);
    font-family: var(--mono);
    font-size: 0.95rem;
    border-radius: 8px;
    padding: 9px 10px;
    -webkit-appearance: none;
  }
  .formula-field input:focus{
    outline: none;
    border-color: color-mix(in srgb, var(--accent) 50%, transparent);
  }

  .formula-solve{
    width: 100%;
    appearance: none;
    border: none;
    background: var(--accent);
    color: #062015;
    font-weight: 700;
    font-family: var(--mono);
    font-size: 0.95rem;
    padding: 12px 0;
    border-radius: 10px;
    cursor: pointer;
    -webkit-tap-highlight-color: transparent;
  }
  .formula-solve:hover{ filter: brightness(1.05); }

  .formula-error{
    color: var(--accent-2);
    font-size: 0.8rem;
    margin: -4px 0 12px;
  }

  /* ---------- PHOTO / CAMERA PANEL ---------- */

  .photo-panel{
    display: flex;
    flex-direction: column;
    gap: 14px;
    border-radius: 12px;
    transition: box-shadow 0.15s ease;
  }

  .photo-panel.drag-over{
    box-shadow: 0 0 0 2px var(--accent);
  }

  .photo-panel.drag-over .photo-intro{
    background: var(--bg-2);
    border-color: var(--accent);
    border-style: dashed;
  }

  .photo-intro{
    text-align: center;
    background: var(--bg-2);
    border: 1px solid rgba(244,241,230,0.08);
    border-radius: 12px;
    padding: 20px 16px;
    transition: border-color 0.15s ease;
  }
  .photo-intro > i{ font-size: 2rem; color: var(--accent); }
  .photo-intro p{
    font-size: 0.85rem;
    color: var(--chalk-dim);
    margin: 10px 0;
  }
  .photo-warning{
    font-size: 0.72rem !important;
    color: var(--chalk-faint) !important;
    line-height: 1.4;
  }

  .photo-actions{
    display: flex;
    gap: 8px;
    justify-content: center;
    flex-wrap: wrap;
    margin-top: 10px;
  }

  .photo-btn{
    appearance: none;
    border: none;
    background: var(--accent);
    color: #062015;
    font-weight: 700;
    font-family: var(--mono);
    font-size: 0.85rem;
    padding: 10px 16px;
    border-radius: 10px;
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    gap: 7px;
    -webkit-tap-highlight-color: transparent;
  }
  .photo-btn:hover{ filter: brightness(1.05); }
  .photo-btn-ghost{
    background: var(--key-func);
    color: var(--chalk-dim);
    border: 1px solid var(--key-border);
    font-weight: 600;
  }
  .photo-upload{ position: relative; }

  .photo-camera{
    background: #000;
    border-radius: 12px;
    overflow: hidden;
    padding: 10px;
  }
  .photo-camera video{
    width: 100%;
    max-height: 320px;
    border-radius: 8px;
    display: block;
    background: #000;
  }

  .photo-preview{
    border-radius: 12px;
    overflow: hidden;
    border: 1px solid rgba(244,241,230,0.08);
  }
  .photo-preview img{
    width: 100%;
    display: block;
    max-height: 260px;
    object-fit: contain;
    background: var(--bg-2);
  }

  .photo-loading{
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    padding: 20px;
    color: var(--chalk-dim);
    font-size: 0.85rem;
  }
  .photo-loading[hidden]{ display: none; }

  .spinner{
    width: 20px;
    height: 20px;
    border-radius: 50%;
    border: 3px solid var(--key-border);
    border-top-color: var(--accent);
    animation: spin 0.8s linear infinite;
  }
  @keyframes spin{ to{ transform: rotate(360deg); } }

  .photo-result{
    background: var(--bg-2);
    border: 1px solid rgba(244,241,230,0.08);
    border-radius: 12px;
    padding: 14px;
  }
  .photo-result label{
    display: flex;
    align-items: center;
    gap: 6px;
    font-size: 0.75rem;
    color: var(--chalk-dim);
    margin-bottom: 8px;
  }
  .photo-result input{
    width: 100%;
    background: var(--bg);
    border: 1px solid var(--key-border);
    color: var(--chalk);
    font-family: var(--mono);
    font-size: 1rem;
    border-radius: 8px;
    padding: 10px;
    margin-bottom: 10px;
    -webkit-appearance: none;
  }
  .photo-result input:focus{ outline: none; border-color: color-mix(in srgb, var(--accent) 50%, transparent); }
  .photo-error{
    color: var(--accent-2);
    font-size: 0.8rem;
    margin: 8px 0 0;
  }

  #photoCanvas{ display: none; }

  /* ---------- STUDY / RECOMMENDATIONS BOX ---------- */

  .study-box{
    margin-top: 22px;
    padding-top: 16px;
    border-top: 1px dashed rgba(244,241,230,0.18);
  }
  .study-box h3{
    font-family: var(--hand);
    font-size: 1.3rem;
    margin: 0 0 10px;
    color: var(--chalk-dim);
    display: flex;
    align-items: center;
    gap: 8px;
  }
  .study-links{
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
  }
  .study-link{
    display: inline-flex;
    align-items: center;
    gap: 7px;
    text-decoration: none;
    background: var(--key-func);
    border: 1px solid var(--key-border);
    color: var(--chalk-dim);
    font-size: 0.78rem;
    padding: 8px 12px;
    border-radius: 20px;
    transition: border-color 0.15s ease, color 0.15s ease;
  }
  .study-link:hover{ border-color: color-mix(in srgb, var(--accent) 50%, transparent); color: var(--accent); }
  .study-link i{ font-size: 0.95rem; }

  /* ---------- BOARD (chalkboard explanation panel) ---------- */

  .board{
    background: var(--board);
    color: var(--chalk);
    border: 10px solid var(--wood);
    border-radius: 4px;
    box-shadow: 0 26px 46px rgba(0,0,0,0.4), 0 0 0 1px var(--wood-dark) inset;
    padding: 22px 24px 20px;
    min-height: 420px;
    position: relative;
    background-image:
      repeating-linear-gradient(0deg, var(--board-line) 0px, transparent 1px, transparent 34px),
      var(--board);
  }

  .board-head{
    display: flex;
    align-items: baseline;
    justify-content: space-between;
    gap: 12px;
    border-bottom: 1px dashed rgba(244,241,230,0.18);
    padding-bottom: 10px;
    margin-bottom: 14px;
    flex-wrap: wrap;
  }

  .board-head h2{
    font-family: var(--hand);
    font-weight: 600;
    font-size: 1.9rem;
    margin: 0;
  }

  .board-sub{
    font-size: 0.8rem;
    color: var(--chalk-faint);
  }

  .steps-empty{
    font-family: var(--hand);
    font-size: 1.25rem;
    color: var(--chalk-faint);
    margin: 30px 4px;
  }

  .steps{ min-height: 60px; }

  .step-line{
    display: flex;
    align-items: baseline;
    gap: 12px;
    padding: 9px 0;
    border-bottom: 1px solid rgba(244,241,230,0.05);
    animation: chalk-in 0.35s ease both;
    flex-wrap: wrap;
  }
  .step-line:last-child{ border-bottom: none; }

  .step-tag{
    font-family: var(--hand);
    font-size: 1rem;
    color: var(--accent);
    min-width: 22px;
    flex-shrink: 0;
  }

  .step-math{
    font-size: 1rem;
    color: var(--chalk);
    white-space: nowrap;
    overflow-x: auto;
    max-width: 100%;
    scrollbar-width: none;
  }
  .step-math::-webkit-scrollbar{ display:none; }
  .step-math .arrow{ color: var(--chalk-faint); margin: 0 6px; }
  .step-math .out{ color: var(--accent); font-weight: 600; }

  .step-rule{
    font-family: var(--hand);
    font-size: 1.02rem;
    color: var(--chalk-dim);
    margin-left: auto;
    text-align: right;
    white-space: normal;
    padding-left: 10px;
  }

  .step-final{
    margin-top: 14px;
    padding-top: 14px;
    border-top: 2px solid color-mix(in srgb, var(--accent) 35%, transparent);
    display: flex;
    align-items: baseline;
    gap: 10px;
    flex-wrap: wrap;
    animation: chalk-in 0.4s ease both;
  }
  .step-final .label{ font-family: var(--hand); font-size: 1.25rem; color: var(--chalk-dim); }
  .step-final .value{ font-size: 1.5rem; font-weight: 700; color: var(--accent); }

  .step-error{
    font-family: var(--hand);
    font-size: 1.25rem;
    color: var(--accent-2);
    margin: 20px 4px;
  }

  @keyframes chalk-in{
    from{ opacity: 0; transform: translateY(4px); }
    to{ opacity: 1; transform: translateY(0); }
  }

  .rules{
    margin-top: 22px;
    padding-top: 16px;
    border-top: 1px dashed rgba(244,241,230,0.18);
  }
  .rules h3{
    font-family: var(--hand);
    font-size: 1.3rem;
    margin: 0 0 8px;
    color: var(--chalk-dim);
  }
  .rules ol{
    margin: 0;
    padding-left: 20px;
    font-size: 0.85rem;
    color: var(--chalk-faint);
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 4px 18px;
  }
  .rules li::marker{ color: var(--accent); }

  .site-footer{
    text-align: center;
    margin-top: 32px;
    font-size: 0.78rem;
    color: var(--chalk-faint);
    line-height: 1.6;
    padding: 0 8px;
  }

  /* ---------- RESPONSIVE / MOBILE ---------- */

  @media (max-width: 900px){
    .layout{ grid-template-columns: 1fr; gap: 18px; }
    .calculator{ max-width: 480px; margin: 0 auto; width: 100%; }
    .board{ min-height: 0; max-width: 480px; margin: 0 auto; width: 100%; }
    .rules ol{ grid-template-columns: 1fr; }
  }

  @media (max-width: 480px){
    .page{ padding: 16px 12px 40px; }
    .site-header{ margin-bottom: 18px; }
    .tagline{ font-size: 0.85rem; }
    .calculator{ padding: 12px; border-radius: 14px; }
    .display{ padding: 14px 12px 10px; min-height: 78px; }
    .key{ padding: 12px 0; min-height: 46px; font-size: 1rem; }
    .tab{ font-size: 0.62rem; padding: 8px 1px; }
    .tab i{ font-size: 0.9rem; }
    .theme-toggle{ width: 34px; height: 34px; top: 0; right: 0; }
    .photo-intro{ padding: 16px 10px; }
    .board{ padding: 14px 12px 14px; border-width: 8px; }
    .board-head h2{ font-size: 1.6rem; }
    .formula-grid{ grid-template-columns: 1fr; }
    .formula-fields{ grid-template-columns: 1fr; }
    .step-rule{ margin-left: 0; text-align: left; padding-left: 0; width: 100%; }
    .step-final .value{ font-size: 1.3rem; }
  }

  @media (prefers-reduced-motion: reduce){
    .step-line, .step-final{ animation: none; }
    .key{ transition: none; }
  }

  /* =========================================================
     TEMA "MULTÍMETRO" — aplicado à calculadora só quando a
     aba Eletrônica está ativa. Visual inspirado em um
     multímetro digital: carcaça laranja/preta e tela LCD
     verde-acinzentada com dígitos escuros.
  ========================================================= */

  .calculator.theme-multimetro{
    background: linear-gradient(180deg, #ff9d1f, #e07d00);
    border: 1px solid #a85c00;
    box-shadow: 0 24px 50px rgba(0,0,0,0.55), inset 0 1px 0 rgba(255,255,255,0.25);
  }

  .calculator.theme-multimetro .display{
    background: #aebf9c;
    border: 3px solid #23241f;
    border-radius: 8px;
    box-shadow: inset 0 2px 6px rgba(0,0,0,0.35);
  }
  .calculator.theme-multimetro .display-expr{
    color: #3c4a34;
    font-family: var(--mono);
  }
  .calculator.theme-multimetro .display-result{
    color: #1c2418;
    font-family: var(--mono);
    text-shadow: 0 0 1px rgba(28,36,24,0.35);
  }
  .calculator.theme-multimetro .display-result.err{ color: #7a1f1f; }

  .calculator.theme-multimetro .tabbar{
    background: #23241f;
    border: 1px solid #141510;
  }
  .calculator.theme-multimetro .tab{ color: #d8d4c8; }
  .calculator.theme-multimetro .tab.active{
    background: #141510;
    color: #ff9d1f;
    box-shadow: inset 0 0 0 1.5px rgba(255,157,31,0.55);
  }
  .calculator.theme-multimetro .tab-note{ color: #3a2a05; }

  .calculator.theme-multimetro .formula-btn{
    background: #23241f;
    border: 1px solid #141510;
    color: #efe9d8;
  }
  .calculator.theme-multimetro .formula-btn:hover{ border-color: #ff9d1f; }
  .calculator.theme-multimetro .formula-btn .fname{ color: #ff9d1f; }
  .calculator.theme-multimetro .formula-btn .fdesc{ color: #b8b2a0; }

  .calculator.theme-multimetro .formula-form{
    background: #23241f;
    border: 1px solid #141510;
  }
  .calculator.theme-multimetro .formula-form-title{ color: #ff9d1f; }
  .calculator.theme-multimetro .formula-form-desc{ color: #b8b2a0; }
  .calculator.theme-multimetro .formula-back{
    background: #141510;
    border: 1px solid #3a3b34;
    color: #efe9d8;
  }
  .calculator.theme-multimetro .formula-field label{ color: #d8d4c8; }
  .calculator.theme-multimetro .formula-field input{
    background: #aebf9c;
    border: 2px solid #141510;
    color: #1c2418;
    font-family: var(--mono);
  }
  .calculator.theme-multimetro .formula-field input:focus{ border-color: #ff9d1f; }
  .calculator.theme-multimetro .formula-solve{
    background: #cc2222;
    color: #fff2ea;
  }
  .calculator.theme-multimetro .formula-solve:hover{ filter: brightness(1.08); }
  .calculator.theme-multimetro .formula-error{ color: #3a0d0d; font-weight: 700; }

  /* =========================================================
     TEMA "CADERNO" — aplicado à calculadora só quando a
     aba Fórmulas está ativa. Visual inspirado numa folha de
     caderno pautado com espiral, anotações em tinta azul e
     fórmulas coladas como post-its tortos na página.
  ========================================================= */

  .calculator.theme-formulas{
    position: relative;
    padding-top: 40px;
    background:
      repeating-linear-gradient(180deg, transparent 0 27px, rgba(43,76,140,0.10) 27px 28px),
      linear-gradient(180deg, #fbf7ea, #f3ecd6);
    border: 1px solid #d9cba3;
    border-radius: 6px;
    box-shadow: 0 24px 50px rgba(80,60,20,0.22), inset 0 1px 0 rgba(255,255,255,0.6);
  }

  .calculator.theme-formulas::before{
    content: '';
    position: absolute;
    top: 8px; left: 24px; right: 24px; height: 14px;
    background-image: radial-gradient(circle, #8f8264 0 4px, transparent 5px);
    background-size: 26px 14px;
    background-repeat: repeat-x;
    background-position: center;
    opacity: 0.6;
  }

  .calculator.theme-formulas::after{
    content: 'anotações';
    position: absolute;
    top: 10px; right: 20px;
    font-family: var(--hand);
    font-size: 1rem;
    color: #1a3c8f;
    opacity: 0.5;
    transform: rotate(-4deg);
  }

  .calculator.theme-formulas .display{
    background:
      repeating-linear-gradient(180deg, transparent 0 26px, rgba(43,76,140,0.14) 26px 27px),
      #fffdf6;
    border: 1px solid #d9cba3;
    border-radius: 4px;
    box-shadow: inset 0 1px 4px rgba(80,60,20,0.15);
    position: relative;
  }
  .calculator.theme-formulas .display::before{
    content: '';
    position: absolute;
    top: 0; bottom: 0; left: 26px;
    width: 1px;
    background: rgba(196,64,64,0.35);
  }
  .calculator.theme-formulas .display-expr{ color: rgba(26,60,143,0.55); font-family: var(--hand); font-size: 1.1rem; }
  .calculator.theme-formulas .display-result{ color: #1a3c8f; font-family: var(--hand); font-weight: 700; }
  .calculator.theme-formulas .display-result.err{ color: #b23a3a; }

  .calculator.theme-formulas .tabbar{
    background: #f3ecd6;
    border: 1px solid #d9cba3;
    border-radius: 6px;
  }
  .calculator.theme-formulas .tab{ color: #7a6a45; }
  .calculator.theme-formulas .tab.active{
    background: #fffdf6;
    color: #1a3c8f;
    box-shadow: inset 0 0 0 1.5px rgba(26,60,143,0.4);
  }

  .calculator.theme-formulas .formula-grid{ gap: 12px; padding: 4px 2px; }
  .calculator.theme-formulas .formula-btn{
    background: #fff8c4;
    border: 1px solid rgba(0,0,0,0.06);
    border-radius: 2px;
    color: #1a3c8f;
    box-shadow: 2px 3px 6px rgba(80,60,20,0.25);
    transform: rotate(-1.2deg);
  }
  .calculator.theme-formulas .formula-btn:nth-child(even){
    background: #d9ecff;
    transform: rotate(1.2deg);
  }
  .calculator.theme-formulas .formula-btn:nth-child(3n){
    background: #ffd9e6;
    transform: rotate(-0.8deg);
  }
  .calculator.theme-formulas .formula-btn:hover{ transform: rotate(0deg) scale(1.02); border-color: #1a3c8f; }
  .calculator.theme-formulas .formula-btn .fname{
    color: #1a3c8f;
    font-family: var(--hand);
    font-size: 1.15rem;
    font-weight: 700;
  }
  .calculator.theme-formulas .formula-btn .fdesc{ color: #4a4530; }

  .calculator.theme-formulas .formula-form{
    background: #fffdf6;
    border: 1px solid #d9cba3;
    border-radius: 4px;
    box-shadow: 0 4px 10px rgba(80,60,20,0.12);
  }
  .calculator.theme-formulas .formula-form-title{ color: #1a3c8f; }
  .calculator.theme-formulas .formula-form-desc{ color: #7a6a45; }
  .calculator.theme-formulas .formula-back{
    background: #f3ecd6;
    border: 1px solid #d9cba3;
    color: #1a3c8f;
  }
  .calculator.theme-formulas .formula-field label{ color: #7a6a45; font-family: var(--hand); font-size: 0.95rem; }
  .calculator.theme-formulas .formula-field input{
    background: #fffdf6;
    border: 1px solid #c9a876;
    border-radius: 3px;
    color: #1a3c8f;
    font-family: var(--hand);
    font-size: 1.15rem;
  }
  .calculator.theme-formulas .formula-field input:focus{ border-color: #1a3c8f; }
  .calculator.theme-formulas .formula-solve{
    background: #1a3c8f;
    color: #fffdf6;
    border-radius: 4px;
  }
  .calculator.theme-formulas .formula-solve:hover{ filter: brightness(1.1); }
  .calculator.theme-formulas .formula-error{ color: #b23a3a; font-weight: 700; }

  @media (max-width: 480px){
    .calculator.theme-foto{ padding-top: 34px; }
    .calculator.theme-foto .camera-lens{ width: 56px; height: 56px; top: 10px; }
    .calculator.theme-foto .camera-hump{ width: 62px; height: 16px; top: -12px; }
    .calculator.theme-foto .camera-flash{ top: 14px; left: calc(50% - 76px); width: 20px; height: 13px; }
    .calculator.theme-foto .camera-shutter{ top: 12px; right: 14px; width: 16px; height: 16px; }
  }

  /* =========================================================
     TEMA "CÂMERA" — aplicado à calculadora só quando a
     aba Foto está ativa. O corpo da calculadora ganha uma
     "carcaça" com formato de câmera de verdade: corcova de
     visor, lente com anéis, flash, botão obturador e grip
     emborrachado na lateral.
  ========================================================= */

  .camera-deco{ display: none; }
  .calculator.theme-foto .camera-deco{ display: block; }

  .calculator.theme-foto{
    position: relative;
    padding-top: 96px;
    border-radius: 26px 26px 14px 14px;
    background:
      repeating-linear-gradient(135deg, rgba(255,255,255,0.02) 0 2px, transparent 2px 6px),
      linear-gradient(180deg, #2c2c2c, #131313);
    border: 1px solid rgba(255,255,255,0.10);
    box-shadow: 0 24px 50px rgba(0,0,0,0.6), inset 0 1px 0 rgba(255,255,255,0.05);
  }

  .camera-hump{
    position: absolute;
    top: -16px; left: 50%;
    transform: translateX(-50%);
    width: 84px; height: 22px;
    background: linear-gradient(180deg, #3d3d3d, #151515);
    border: 1px solid rgba(255,255,255,0.15);
    border-radius: 9px 9px 3px 3px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.5), inset 0 -2px 4px rgba(0,0,0,0.4);
  }

  .camera-strap{
    position: absolute;
    top: 4px;
    width: 13px; height: 13px;
    border-radius: 50%;
    background: #222;
    border: 2px solid #5a5a5a;
    box-shadow: inset 0 0 3px rgba(0,0,0,0.6);
  }
  .camera-strap-l{ left: 12px; }
  .camera-strap-r{ right: 12px; }

  .camera-flash{
    position: absolute;
    top: 20px; left: calc(50% - 100px);
    width: 26px; height: 16px;
    border-radius: 3px;
    background: linear-gradient(180deg, #e6ecef, #a9b3ba);
    border: 1px solid #7c868c;
    box-shadow: inset 0 0 3px rgba(255,255,255,0.7);
  }

  .camera-shutter{
    position: absolute;
    top: 18px; right: 22px;
    width: 22px; height: 22px;
    border-radius: 50%;
    background: radial-gradient(circle at 35% 30%, #ff7a5c, #b81f1f 78%);
    border: 2px solid #ddd;
    box-shadow: 0 2px 3px rgba(0,0,0,0.55);
  }

  .camera-lens{
    position: absolute;
    top: 16px; left: 50%;
    transform: translateX(-50%);
    width: 76px; height: 76px;
    border-radius: 50%;
    background: radial-gradient(circle at 35% 30%, #4c4c4c 0%, #1a1a1a 55%, #000 100%);
    border: 4px solid #565656;
    box-shadow: 0 0 0 2px #000, 0 6px 10px rgba(0,0,0,0.55), inset 0 0 10px rgba(0,0,0,0.8);
  }
  .camera-lens-ring{
    position: absolute;
    inset: 11px;
    border-radius: 50%;
    border: 2px solid rgba(255,255,255,0.16);
  }
  .camera-lens-glass{
    position: absolute;
    inset: 23px;
    border-radius: 50%;
    background: radial-gradient(circle at 30% 25%, rgba(120,190,255,0.55), rgba(10,10,15,0.92) 62%);
    box-shadow: inset 0 0 12px rgba(0,0,0,0.85);
  }

  .camera-grip{
    position: absolute;
    top: 108px; bottom: 16px; right: 3px;
    width: 15px;
    border-radius: 6px;
    background: repeating-linear-gradient(135deg, #1c1c1c 0 4px, #060606 4px 8px);
    box-shadow: inset 0 0 4px rgba(0,0,0,0.7);
  }

  .calculator.theme-foto .display{
    background: #101010;
    border: 1px solid rgba(255,255,255,0.10);
    box-shadow: inset 0 2px 8px rgba(0,0,0,0.6);
  }
  .calculator.theme-foto .display-expr{ color: rgba(255,255,255,0.35); }
  .calculator.theme-foto .display-result{ color: #f0f0f0; }
  .calculator.theme-foto .display-result.err{ color: #ff5a3c; }

  .calculator.theme-foto .tabbar{
    background: #141414;
    border: 1px solid rgba(255,255,255,0.08);
  }
  .calculator.theme-foto .tab{ color: #8a8a8a; }
  .calculator.theme-foto .tab.active{
    background: #000;
    color: #ff5a3c;
    box-shadow: inset 0 0 0 1.5px rgba(255,90,60,0.5);
  }

  .calculator.theme-foto .photo-intro{
    background: #1c1c1c;
    border: 1px solid rgba(255,255,255,0.08);
  }
  .calculator.theme-foto .photo-intro > i{ color: #ff5a3c; }
  .calculator.theme-foto .photo-intro p{ color: #cfcfcf; }
  .calculator.theme-foto .photo-warning{ color: #8a8a8a !important; }
  .calculator.theme-foto .photo-panel.drag-over{ box-shadow: 0 0 0 2px #ff5a3c; }
  .calculator.theme-foto .photo-panel.drag-over .photo-intro{ background: #141414; border-color: #ff5a3c; }

  .calculator.theme-foto .photo-btn{
    background: linear-gradient(180deg, #3d3d3d, #202020);
    color: #f0f0f0;
    border: 1px solid rgba(255,255,255,0.15);
    box-shadow: 0 2px 0 rgba(0,0,0,0.55), inset 0 1px 0 rgba(255,255,255,0.08);
  }
  .calculator.theme-foto .photo-btn:hover{ border-color: #ff5a3c; }
  .calculator.theme-foto #btnCapture{
    background: radial-gradient(circle at 35% 30%, #ff7a5c, #cc2222 75%);
    border-color: #eee;
  }
  .calculator.theme-foto .photo-btn-ghost{
    background: #141414;
    color: #cfcfcf;
    border: 1px solid rgba(255,255,255,0.12);
  }

  .calculator.theme-foto .photo-camera{ background: #000; border: 1px solid #333; }

  .calculator.theme-foto .photo-preview{ border: 1px solid rgba(255,255,255,0.12); }
  .calculator.theme-foto .photo-preview img{ background: #101010; }

  .calculator.theme-foto .photo-loading{ color: #cfcfcf; }
  .calculator.theme-foto .spinner{ border-color: rgba(255,255,255,0.15); border-top-color: #ff5a3c; }

  .calculator.theme-foto .photo-result{
    background: #1c1c1c;
    border: 1px solid rgba(255,255,255,0.08);
  }
  .calculator.theme-foto .photo-result label{ color: #cfcfcf; }
  .calculator.theme-foto .photo-result input{
    background: #101010;
    border: 1px solid rgba(255,255,255,0.15);
    color: #f0f0f0;
  }
  .calculator.theme-foto .photo-result input:focus{ border-color: #ff5a3c; }
  .calculator.theme-foto .photo-error{ color: #ff5a3c; }