/* internet-and-data-usage-calculator.css */
:root {
    --primary-blue: #0052cc;
    --hero-gradient: linear-gradient(135deg, #0061ff 0%, #0033aa 100%);
    --bg-light: #f8fafc;
    --white: #ffffff;
    --text-main: #1e293b;
    --text-muted: #64748b;
    --border-color: #e2e8f0;
    --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    --radius: 12px;
    --transition: all 0.3s ease;
    --success-bg: #ecfdf5;
    --success-text: #047857;
    --warning-bg: #fff7ed;
    --warning-text: #c2410c;
    --danger-bg: #fef2f2;
    --danger-text: #b91c1c;
  }
  
  *,
  *::before,
  *::after {
    box-sizing: border-box;
  }
  
  html {
    scroll-behavior: smooth;
  }
  
  body {
    margin: 0;
    font-family: "Inter", sans-serif;
    color: var(--text-main);
    background: var(--white);
    line-height: 1.7;
  }
  
  a {
    color: var(--primary-blue);
    text-decoration: none;
    transition: var(--transition);
  }
  
  a:hover {
    text-decoration: underline;
  }
  
  img,
  canvas {
    display: block;
    max-width: 100%;
  }
  
  .container {
    width: 100%;
    max-width: 1200px;
    padding: 0 16px;
    margin: 0 auto;
  }
  
  .hidden {
    display: none !important;
  }
  
  /* HERO */
  
  .hero {
    background: var(--hero-gradient);
    color: var(--white);
    padding: 40px 0 40px;
  }
  
  .breadcrumb {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 8px;
    margin-bottom: 26px;
    font-size: 0.92rem;
  }
  
  .breadcrumb a,
  .breadcrumb span {
    color: rgba(255, 255, 255, 0.9);
  }
  
  .breadcrumb a:hover {
    color: var(--white);
  }
  
  .hero-content {
    max-width: 820px;
  }
  
  .hero h1 {
    margin: 0 0 16px;
    color: var(--white);
    font-size: clamp(2.15rem, 5vw, 3.6rem);
    line-height: 1.08;
    letter-spacing: -0.04em;
  }
  
  /* BUTTONS */
  
  .btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-height: 48px;
    padding: 12px 18px;
    border: 1px solid transparent;
    border-radius: var(--radius);
    font: inherit;
    font-size: 0.98rem;
    font-weight: 800;
    cursor: pointer;
    transition: var(--transition);
    text-align: center;
    white-space: normal;
  }
  
  .btn:hover {
    transform: translateY(-1px);
    text-decoration: none;
  }
  
  .btn-primary {
    color: var(--white);
    background: var(--primary-blue);
    box-shadow: var(--shadow-sm);
  }
  
  .btn-primary:hover {
    background: #003f9e;
  }
  
  .btn-secondary {
    color: var(--text-main);
    background: var(--white);
    border-color: var(--border-color);
  }
  
  .btn-secondary:hover {
    background: var(--bg-light);
  }
  
  /* MAIN */
  
  .main-area {
    padding: 56px 0;
    background: var(--bg-light);
  }
  
  .calculator-layout {
    display: grid;
    grid-template-columns: minmax(0, 1.08fr) minmax(0, 0.92fr);
    gap: 24px;
    align-items: start;
  }
  
  .calculator-card {
    min-width: 0;
    padding: 26px;
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    background: var(--white);
    box-shadow: var(--shadow-sm);
  }
  
  .card-heading {
    display: flex;
    gap: 16px;
    margin-bottom: 24px;
  }
  
  .card-heading h2 {
    margin: 0 0 8px;
    font-size: clamp(1.35rem, 2vw, 1.7rem);
    line-height: 1.25;
  }
  
  .card-heading p {
    margin: 0;
    color: var(--text-muted);
  }
  
  .card-icon {
    width: 54px;
    height: 54px;
    min-width: 54px;
    border-radius: 14px;
    background: rgba(0, 82, 204, 0.08);
    color: var(--primary-blue);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    font-weight: 900;
    letter-spacing: -0.04em;
  }
  
  .form-subheading {
    margin: 24px 0 16px;
    padding-top: 4px;
    font-size: 1.05rem;
    line-height: 1.35;
  }
  
  /* FORM */
  
  .form-grid {
    display: grid;
    gap: 18px;
  }
  
  .form-grid.two-col {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
  
  .form-group {
    display: flex;
    flex-direction: column;
    gap: 8px;
    min-width: 0;
    margin-bottom: 18px;
  }
  
  .form-group label {
    color: var(--text-main);
    font-weight: 800;
    line-height: 1.35;
  }
  
  .form-group small {
    display: block;
    color: var(--text-muted);
    line-height: 1.45;
  }
  
  .form-group input,
  .form-group select {
    width: 100%;
    min-height: 48px;
    padding: 12px 14px;
    border: 1px solid var(--border-color);
    border-radius: 10px;
    background: var(--white);
    color: var(--text-main);
    font: inherit;
    transition: var(--transition);
  }
  
  .form-group input:focus,
  .form-group select:focus {
    outline: none;
    border-color: var(--primary-blue);
    box-shadow: 0 0 0 3px rgba(0, 82, 204, 0.12);
  }
  
  .input-suffix {
    display: flex;
    align-items: stretch;
    width: 100%;
  }
  
  .input-suffix input {
    border-top-right-radius: 0;
    border-bottom-right-radius: 0;
  }
  
  .input-suffix span {
    min-width: 76px;
    padding: 0 12px;
    border: 1px solid var(--border-color);
    border-left: 0;
    border-radius: 0 10px 10px 0;
    background: var(--bg-light);
    color: var(--text-muted);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    font-weight: 800;
    white-space: nowrap;
  }
  
  .note-box {
    margin-top: 6px;
    padding: 16px 18px;
    border-radius: 12px;
    border: 1px solid rgba(194, 65, 12, 0.16);
    background: var(--warning-bg);
    color: var(--warning-text);
  }
  
  .form-message {
    display: none;
    margin-top: 18px;
    padding: 14px 16px;
    border-radius: 10px;
    font-weight: 800;
  }
  
  .form-message.error {
    display: block;
    color: var(--danger-text);
    background: var(--danger-bg);
    border: 1px solid rgba(185, 28, 28, 0.14);
  }
  
  .form-message.success {
    display: block;
    color: var(--success-text);
    background: var(--success-bg);
    border: 1px solid rgba(4, 120, 87, 0.14);
  }
  
  .button-row {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
    width: 100%;
    margin-top: 22px;
  }
  
  .button-row .btn {
    max-width: 100%;
  }
  
  /* RESULTS */
  
  .results-card {
    position: sticky;
    top: 18px;
    min-width: 0;
    max-width: 100%;
    overflow: hidden;
  }
  
  .results-placeholder {
    width: 100%;
    max-width: 100%;
    padding: 44px 18px;
    text-align: center;
  }
  
  .placeholder-icon {
    width: 76px;
    height: 76px;
    margin: 0 auto 18px;
    border-radius: 50%;
    background: rgba(0, 82, 204, 0.08);
    color: var(--primary-blue);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    font-size: 1.55rem;
    font-weight: 900;
  }
  
  .results-placeholder h3 {
    margin: 0 0 10px;
    font-size: 1.25rem;
  }
  
  .results-placeholder p {
    margin: 0;
    color: var(--text-muted);
  }
  
  .results-content {
    width: 100%;
    max-width: 100%;
    min-width: 0;
  }
  
  .mini-label {
    display: inline-block;
    margin-bottom: 8px;
    color: var(--primary-blue);
    font-size: 0.78rem;
    font-weight: 900;
    letter-spacing: 0.08em;
    text-transform: uppercase;
  }
  
  .results-content h2 {
    margin: 0 0 10px;
    color: var(--primary-blue);
    font-size: clamp(2.15rem, 5vw, 3rem);
    line-height: 1.05;
    overflow-wrap: anywhere;
    word-break: break-word;
  }
  
  #usageMessage {
    display: block;
    max-width: 100%;
    margin: 0 0 20px;
    color: var(--text-muted);
    line-height: 1.6;
    overflow-wrap: anywhere;
  }
  
  .result-grid {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 14px;
    min-width: 0;
    margin: 20px 0;
  }
  
  .result-tile {
    min-width: 0;
    width: 100%;
    padding: 16px;
    border: 1px solid var(--border-color);
    border-radius: 12px;
    background: var(--white);
  }
  
  .result-tile span {
    display: block;
    max-width: 100%;
    margin-bottom: 8px;
    color: var(--text-muted);
    font-size: 0.92rem;
    overflow-wrap: anywhere;
  }
  
  .result-tile strong {
    display: block;
    max-width: 100%;
    color: var(--text-main);
    font-size: 1.04rem;
    line-height: 1.35;
    overflow-wrap: anywhere;
    word-break: break-word;
  }
  
  .usage-level {
    margin: 20px 0;
    padding: 16px 18px;
    border-radius: 12px;
    border: 1px solid var(--border-color);
  }
  
  .usage-level.success {
    color: var(--success-text);
    background: var(--success-bg);
    border-color: rgba(4, 120, 87, 0.14);
  }
  
  .usage-level.warning {
    color: var(--warning-text);
    background: var(--warning-bg);
    border-color: rgba(194, 65, 12, 0.16);
  }
  
  .usage-level.danger {
    color: var(--danger-text);
    background: var(--danger-bg);
    border-color: rgba(185, 28, 28, 0.14);
  }
  
  .usage-level strong {
    display: block;
    margin-bottom: 6px;
  }
  
  .usage-level p {
    margin: 0;
  }
  
  /* CONTENT */
  
  .content-section {
    margin-top: 28px;
    padding: 0;
  }
  
  .content-section h2 {
    margin: 0 0 14px;
    font-size: clamp(1.45rem, 3vw, 2rem);
    line-height: 1.25;
    letter-spacing: -0.02em;
  }
  
  .content-section h3 {
    margin: 0 0 10px;
    font-size: 1.08rem;
    line-height: 1.35;
  }
  
  .content-section p {
    margin: 0 0 16px;
  }
  
  .content-section p:last-child {
    margin-bottom: 0;
  }
  
  .formula-grid,
  .mini-grid,
  .tip-grid,
  .related-grid {
    display: grid;
    gap: 16px;
    margin: 20px 0;
  }
  
  .formula-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
  
  .formula-box {
    padding: 20px;
    border: 1px solid rgba(0, 82, 204, 0.14);
    border-radius: 12px;
    background: #f8fbff;
  }
  
  .formula-box p {
    margin: 0 0 10px;
    color: var(--text-main);
    font-weight: 700;
  }
  
  .formula-box p:last-child {
    margin-bottom: 0;
  }
  
  .mini-grid {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
  
  .mini-grid > div,
  .tip-grid > div {
    padding: 20px;
    border: 1px solid var(--border-color);
    border-radius: 12px;
    background: var(--white);
  }
  
  .tip-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
  
  .step-list {
    margin: 18px 0 0;
    padding-left: 22px;
  }
  
  .step-list li {
    margin-bottom: 10px;
  }
  
  .table-wrap {
    width: 100%;
    max-width: 100%;
    min-width: 0;
    overflow-x: auto;
    margin: 20px 0 0;
    -webkit-overflow-scrolling: touch;
  }
  
  .info-table {
    width: 100%;
    min-width: 640px;
    border-collapse: collapse;
    background: var(--white);
  }
  
  .wide-table {
    min-width: 780px;
  }
  
  .info-table th,
  .info-table td {
    padding: 14px 16px;
    border: 1px solid var(--border-color);
    text-align: left;
    vertical-align: top;
  }
  
  .info-table th {
    background: #f1f5f9;
    color: var(--text-main);
    font-weight: 900;
  }
  
  .info-table td {
    color: var(--text-main);
  }
  
  .related-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
  
  .related-grid a {
    display: block;
    padding: 18px;
    border: 1px solid var(--border-color);
    border-radius: 12px;
    background: var(--white);
    font-weight: 800;
  }
  
  .related-grid a:hover {
    background: #f8fbff;
    border-color: rgba(0, 82, 204, 0.18);
    text-decoration: none;
    transform: translateY(-1px);
  }
  
  /* FAQ */
  
  .faq-section details {
    border: 1px solid var(--border-color);
    border-radius: 12px;
    background: var(--white);
    overflow: hidden;
  }
  
  .faq-section details + details {
    margin-top: 12px;
  }
  
  .faq-section summary {
    padding: 18px 20px;
    cursor: pointer;
    font-weight: 900;
    list-style: none;
    display: flex;
    justify-content: space-between;
    gap: 16px;
  }
  
  .faq-section summary::-webkit-details-marker {
    display: none;
  }
  
  .faq-section summary::after {
    content: "+";
    color: var(--primary-blue);
    font-weight: 900;
  }
  
  .faq-section details[open] summary::after {
    content: "−";
  }
  
  .faq-section details p {
    margin: 0;
    padding: 0 20px 20px;
    color: var(--text-muted);
  }
  
  /* CTA */
  
  .final-cta {
    margin-top: 32px;
    padding: 36px 28px;
    border-radius: var(--radius);
    background: var(--hero-gradient);
    color: var(--white);
    text-align: center;
  }
  
  .final-cta h2 {
    margin: 0 0 12px;
    color: var(--white);
    font-size: clamp(1.6rem, 4vw, 2.2rem);
    line-height: 1.2;
  }
  
  .final-cta p {
    max-width: 760px;
    margin: 0 auto 22px;
    color: rgba(255, 255, 255, 0.9);
  }
  
  .final-cta .btn-primary {
    color: var(--primary-blue);
    background: var(--white);
    box-shadow: none;
  }
  
  .final-cta .btn-primary:hover {
    background: #f8fbff;
  }
  
  /* ACCESSIBILITY */
  
  button:focus-visible,
  a:focus-visible,
  input:focus-visible,
  select:focus-visible,
  summary:focus-visible {
    outline: 3px solid rgba(0, 82, 204, 0.35);
    outline-offset: 3px;
  }
  
  /* RESPONSIVE */
  
  @media (max-width: 980px) {
    .calculator-layout {
      grid-template-columns: 1fr;
    }
  
    .results-card {
      position: static;
    }
  
    .mini-grid,
    .related-grid {
      grid-template-columns: repeat(2, minmax(0, 1fr));
    }
  }
  
  @media (max-width: 720px) {
    .hero {
      padding: 20px 0 20px;
    }
  
    .main-area {
      padding: 40px 0;
    }
  
    .calculator-layout {
      width: 100%;
      overflow: hidden;
    }
  
    .calculator-card {
      width: 100%;
      max-width: 100%;
      padding: 22px;
    }
  
    .card-heading {
      flex-direction: column;
    }
  
    .form-grid.two-col,
    .formula-grid,
    .mini-grid,
    .tip-grid,
    .related-grid,
    .result-grid {
      grid-template-columns: 1fr;
    }
  
    .button-row {
      flex-direction: column;
    }
  
    .button-row .btn {
      width: 100%;
    }
  
    .results-content h2 {
      font-size: 2rem;
    }
  
    .final-cta {
      padding: 30px 20px;
      text-align: left;
    }
  
    .final-cta p {
      margin-left: 0;
      margin-right: 0;
    }
  }
  
  @media (max-width: 480px) {
    .container {
      padding: 0 14px;
    }
  
    .hero h1 {
      font-size: 2rem;
    }
  
    .hero-lead {
      font-size: 1rem;
    }
  
    .calculator-card {
      padding: 18px;
    }
  
    .input-suffix span {
      min-width: 64px;
      padding: 0 10px;
      font-size: 0.9rem;
    }
  
    .info-table {
      min-width: 580px;
    }
  
    .wide-table {
      min-width: 720px;
    }
  }