:root {
      --bg:           #f9f9f8;
      --surface:      #ffffff;
      --surface-2:    #f2f2f0;
      --border:       #e2e2de;
      --text-primary: #1a1a18;
      --text-secondary: #5a5a55;
      --text-muted:   #8a8a84;
      --accent:       #2d6a4f;
      --accent-light: #d8ede3;
      --accent-hover: #235c43;
      --btn-secondary-bg: #f2f2f0;
      --btn-secondary-hover: #e5e5e0;
      --progress-bg:  #e2e2de;
      --progress-fill: #2d6a4f;
      --radio-border: #c0c0ba;
      --radio-checked: #2d6a4f;
      --shadow:       0 2px 16px rgba(0,0,0,0.07);
      --shadow-card:  0 4px 24px rgba(0,0,0,0.09);
      --radius:       12px;
      --radius-sm:    8px;
      --radius-lg:    20px;
      --font: 'Georgia', 'Times New Roman', serif;
      --font-ui: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    }
    [data-theme="dark"] {
      --bg:           #111110;
      --surface:      #1c1c1a;
      --surface-2:    #252523;
      --border:       #2e2e2b;
      --text-primary: #f0f0ec;
      --text-secondary: #a8a8a0;
      --text-muted:   #6a6a64;
      --accent:       #52b788;
      --accent-light: #1a3328;
      --accent-hover: #63c99a;
      --btn-secondary-bg: #252523;
      --btn-secondary-hover: #2e2e2b;
      --progress-bg:  #2e2e2b;
      --progress-fill: #52b788;
      --radio-border: #4a4a46;
      --radio-checked: #52b788;
      --shadow:       0 2px 16px rgba(0,0,0,0.3);
      --shadow-card:  0 4px 24px rgba(0,0,0,0.4);
    }
    *, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
    html { font-size: 16px; scroll-behavior: smooth; }
    body {
      font-family: var(--font-ui);
      background: var(--bg);
      color: var(--text-primary);
      min-height: 100vh;
      line-height: 1.6;
      transition: background 0.25s, color 0.25s;
    }
    .page-wrapper { min-height: 100vh; display: flex; flex-direction: column; }
    .site-header {
      position: sticky; top: 0; z-index: 50;
      background: var(--surface);
      border-bottom: 1px solid var(--border);
      box-shadow: var(--shadow);
    }
    .header-inner {
      max-width: 760px; margin: 0 auto; padding: 14px 20px;
      display: flex; align-items: flex-start; justify-content: space-between; gap: 12px;
    }
    .brand-mark {
      width: 112px;
      height: auto;
      object-fit: contain;
      display: block;
      flex-shrink: 0;
    }
    .site-title { font-family: var(--font); font-size: 1.05rem; font-weight: 600; color: var(--text-primary); letter-spacing: -0.01em; }
    .site-subtitle { font-size: 0.78rem; color: var(--text-muted); margin-top: 1px; }
    @media (max-width: 520px) {
      .brand-mark { width: clamp(130px, 42vw, 170px); }
    }
    .btn-theme {
      background: var(--btn-secondary-bg); border: 1px solid var(--border); color: var(--text-secondary);
      border-radius: var(--radius-sm); padding: 7px 13px; font-size: 0.82rem; cursor: pointer;
      transition: background 0.18s, color 0.18s; white-space: nowrap; font-family: var(--font-ui);
    }
    .btn-theme:hover { background: var(--btn-secondary-hover); color: var(--text-primary); }
    .btn-theme:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
    .main-content { flex: 1; max-width: 760px; margin: 0 auto; width: 100%; padding: 32px 20px 60px; }
    .intro-card {
      background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius-lg);
      padding: 36px 32px; margin-bottom: 32px; box-shadow: var(--shadow-card);
    }
    .intro-card h1 { font-family: var(--font); font-size: 1.65rem; font-weight: 700; line-height: 1.3; color: var(--text-primary); margin-bottom: 14px; }
    .intro-card p { color: var(--text-secondary); font-size: 0.97rem; margin-bottom: 10px; line-height: 1.7; }
    .intro-card .start-btn-wrap { margin-top: 24px; }
    .scale-legend {
      background: var(--surface-2); border: 1px solid var(--border); border-radius: var(--radius-sm);
      padding: 14px 18px; margin: 20px 0; font-size: 0.87rem; color: var(--text-secondary);
    }
    .scale-legend strong { display: block; margin-bottom: 8px; color: var(--text-primary); font-size: 0.82rem; text-transform: uppercase; letter-spacing: 0.06em; }
    .scale-legend ol { list-style: none; display: flex; flex-wrap: wrap; gap: 6px 18px; }
    .scale-legend ol li { font-size: 0.84rem; }
    .progress-wrap { margin-bottom: 28px; }
    .progress-label { display: flex; justify-content: space-between; font-size: 0.82rem; color: var(--text-muted); margin-bottom: 8px; }
    .progress-track { height: 5px; background: var(--progress-bg); border-radius: 99px; overflow: hidden; }
    .progress-fill { height: 100%; background: var(--progress-fill); border-radius: 99px; transition: width 0.35s ease; }
    .question-card {
      background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius-lg);
      padding: 32px 28px 28px; box-shadow: var(--shadow-card); animation: fadeSlideIn 0.28s ease;
    }
    @keyframes fadeSlideIn { from { opacity: 0; transform: translateY(10px); } to { opacity: 1; transform: translateY(0); } }
    .question-number { font-size: 0.78rem; text-transform: uppercase; letter-spacing: 0.08em; color: var(--accent); font-weight: 600; margin-bottom: 12px; }
    .question-text { font-family: var(--font); font-size: 1.18rem; line-height: 1.55; color: var(--text-primary); margin-bottom: 26px; }
    .likert-group { display: flex; flex-direction: column; gap: 10px; margin-bottom: 28px; }
    .likert-option {
      display: flex; align-items: center; gap: 14px; padding: 13px 16px; border: 1.5px solid var(--border);
      border-radius: var(--radius-sm); cursor: pointer; transition: border-color 0.18s, background 0.18s; background: var(--surface);
    }
    .likert-option:hover { border-color: var(--accent); background: var(--accent-light); }
    .likert-option.selected { border-color: var(--accent); background: var(--accent-light); }
    .likert-option input[type="radio"] { position: absolute; opacity: 0; width: 0; height: 0; }
    .radio-visual {
      width: 20px; height: 20px; border-radius: 50%; border: 2px solid var(--radio-border); flex-shrink: 0;
      display: flex; align-items: center; justify-content: center; transition: border-color 0.18s; background: var(--surface);
    }
    .likert-option.selected .radio-visual { border-color: var(--radio-checked); background: var(--radio-checked); }
    .likert-option.selected .radio-visual::after { content: ''; width: 8px; height: 8px; border-radius: 50%; background: var(--surface); }
    .likert-option:focus-within .radio-visual { outline: 2px solid var(--accent); outline-offset: 2px; }
    .likert-label-text { font-size: 0.93rem; color: var(--text-secondary); line-height: 1.4; }
    .likert-option.selected .likert-label-text { color: var(--text-primary); font-weight: 500; }
    .likert-value { font-size: 0.8rem; color: var(--text-muted); margin-left: auto; flex-shrink: 0; }
    .likert-option.selected .likert-value { color: var(--accent); font-weight: 600; }
    .validation-msg { font-size: 0.84rem; color: #c0392b; margin-top: -18px; margin-bottom: 14px; display: none; }
    .validation-msg.visible { display: block; }
    .submitting-msg { font-size: 0.93rem; color: var(--text-muted); padding: 10px 0; display: none; }
    .submitting-msg.visible { display: block; }
    .processing-overlay {
      position: fixed;
      inset: 0;
      z-index: 1000;
      display: none;
      align-items: center;
      justify-content: center;
      padding: 20px;
      background: rgba(17, 17, 16, 0.42);
      backdrop-filter: blur(6px);
    }
    .processing-overlay.visible { display: flex; }
    .processing-card {
      width: min(100%, 520px);
      background: var(--surface);
      border: 1px solid var(--border);
      border-radius: var(--radius-lg);
      box-shadow: var(--shadow-card);
      padding: 30px 26px 24px;
      text-align: center;
    }
    .processing-title {
      font-family: var(--font);
      font-size: 1.22rem;
      line-height: 1.45;
      margin-bottom: 8px;
      color: var(--text-primary);
    }
    .processing-status {
      color: var(--text-secondary);
      font-size: 0.95rem;
      min-height: 1.6em;
      margin-bottom: 18px;
    }
    .processing-bar {
      position: relative;
      height: 6px;
      border-radius: 999px;
      overflow: hidden;
      background: var(--progress-bg);
      margin-bottom: 18px;
    }
    .processing-bar::before {
      content: '';
      position: absolute;
      inset: 0;
      background: linear-gradient(90deg, transparent 0%, var(--progress-fill) 50%, transparent 100%);
      width: 40%;
      border-radius: 999px;
      animation: processingShift 1.1s linear infinite;
    }
    @keyframes processingShift {
      from { transform: translateX(-130%); }
      to { transform: translateX(330%); }
    }
    .processing-error {
      display: none;
      margin-top: 14px;
      color: var(--text-secondary);
      font-size: 0.92rem;
    }
    .processing-error.visible { display: block; }
    .processing-error .btn { margin-top: 14px; }
    .processing-blocked {
      overflow: hidden;
      user-select: none;
    }
    .email-section { margin-bottom: 22px; }
    .email-section label { display:block; font-size:0.85rem; font-weight:600; color:var(--text-primary); margin-bottom:4px; font-family: var(--font-ui); }
    .email-section p { font-size:0.8rem; color:var(--text-muted); margin-bottom:10px; line-height: 1.5; }
    .email-section input {
      width:100%; padding:11px 14px; border:1.5px solid var(--border); border-radius:var(--radius-sm);
      background:var(--surface); color:var(--text-primary); font-size:0.93rem; font-family:var(--font-ui);
    }
    .email-section input:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
    .nav-buttons { display: flex; gap: 12px; align-items: center; flex-wrap: wrap; }
    .btn {
      display: inline-flex; align-items: center; justify-content: center; gap: 7px; border-radius: var(--radius-sm);
      font-size: 0.93rem; font-weight: 500; padding: 11px 22px; cursor: pointer; border: none;
      transition: background 0.18s, color 0.18s, opacity 0.18s, transform 0.12s; font-family: var(--font-ui);
      text-decoration: none; letter-spacing: 0.01em;
    }
    .btn:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
    .btn:active { transform: scale(0.98); }
    .btn-primary { background: var(--accent); color: #fff; }
    .btn-primary:hover { background: var(--accent-hover); }
    .btn-secondary { background: var(--btn-secondary-bg); color: var(--text-secondary); border: 1px solid var(--border); }
    .btn-secondary:hover { background: var(--btn-secondary-hover); color: var(--text-primary); }
    .btn-outline { background: transparent; color: var(--accent); border: 1.5px solid var(--accent); }
    .btn-outline:hover { background: var(--accent-light); }
    .btn-reset { background: transparent; color: var(--text-muted); border: none; font-size: 0.82rem; padding: 8px 10px; text-decoration: underline; cursor: pointer; font-family: var(--font-ui); }
    .btn-reset:hover { color: var(--text-secondary); }
    .btn-reset:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
    .hidden { display: none !important; }
    .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; }
    @media (max-width: 520px) {
      .intro-card { padding: 24px 18px; }
      .intro-card h1 { font-size: 1.35rem; }
      .question-card { padding: 22px 16px 20px; }
      .question-text { font-size: 1.05rem; }
      .header-inner { padding: 12px 16px; }
      .main-content { padding: 20px 14px 50px; }
      .nav-buttons { flex-direction: column; align-items: stretch; }
      .nav-buttons .btn { text-align: center; }
    }
    @media (min-width: 600px) {
      .likert-group { display: grid; grid-template-columns: 1fr 1fr; gap: 10px; }
      .likert-group .likert-option:last-child:nth-child(odd) { grid-column: 1 / -1; }
    }
    @media (min-width: 760px) {
      .likert-group { display: flex; flex-direction: row; gap: 8px; }
      .likert-group .likert-option { flex: 1; flex-direction: column; align-items: center; text-align: center; gap: 8px; padding: 14px 8px; }
      .likert-value { margin-left: 0; }
      .likert-group .likert-option:last-child:nth-child(odd) { grid-column: auto; }
    }