:root {
  --bg: #f7f2e7;
  --surface: #ffffff;
  --surface-2: #fbf7ee;
  --ink: #191726;
  --ink-soft: #5a5470;
  --ink-faint: #9089a3;
  --accent: #e0432b;
  --accent-2: #c23621;
  --accent-soft: rgba(224, 67, 43, 0.12);
  --gold: #b4870a;
  --gold-soft: rgba(239, 176, 0, 0.18);
  --line: #e7dec7;
  --line-strong: #d8cba8;
  --good: #2f9e58;
  --good-soft: #e6f4ea;
  --bad: #d64545;
  --bad-soft: #fbe9e9;

  --shadow-sm: 0 1px 2px rgba(25, 23, 38, 0.06), 0 1px 1px rgba(25, 23, 38, 0.04);
  --shadow-md: 0 10px 24px -8px rgba(25, 23, 38, 0.16), 0 2px 8px -2px rgba(25, 23, 38, 0.06);

  --serif: "Futura", "Avenir Next", Avenir, "Century Gothic", system-ui, sans-serif;
  --sans: "Avenir Next", Avenir, "Segoe UI", -apple-system, BlinkMacSystemFont, sans-serif;
  --mono: ui-monospace, "SF Mono", "Cascadia Code", Menlo, Consolas, monospace;

  --color-nom: #1d5fa6; --color-nom-bg: #e5eef8;
  --color-acc: #e0432b; --color-acc-bg: #fbe7e3;
  --color-irr: #b4870a; --color-irr-bg: #faf1d6;
  --color-coo: #0f7168; --color-coo-bg: #e2f2f0;
  --color-sub: #6c4ba6; --color-sub-bg: #eee8f7;
  --color-neg: #b8355f; --color-neg-bg: #f8e5eb;

  --radius: 20px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #131220;
    --surface: #1c1a2c; --surface-2: #211f34;
    --ink: #f3eee1; --ink-soft: #b3abc9; --ink-faint: #867f9c;
    --accent: #ff5b41; --accent-2: #ff7b62; --accent-soft: rgba(255, 91, 65, 0.16);
    --gold: #ffcb3d; --gold-soft: rgba(255, 203, 61, 0.18);
    --line: #33304a; --line-strong: #413c5c;
    --good: #6bc98a; --good-soft: rgba(107, 201, 138, 0.14);
    --bad: #e58080; --bad-soft: rgba(229, 128, 128, 0.14);
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 10px 28px -10px rgba(0, 0, 0, 0.55);

    --color-nom: #5b98e8; --color-nom-bg: rgba(91, 152, 232, 0.16);
    --color-acc: #ff5b41; --color-acc-bg: rgba(255, 91, 65, 0.16);
    --color-irr: #ffcb3d; --color-irr-bg: rgba(255, 203, 61, 0.18);
    --color-coo: #2fb6a8; --color-coo-bg: rgba(47, 182, 168, 0.16);
    --color-sub: #9a7bd6; --color-sub-bg: rgba(154, 123, 214, 0.18);
    --color-neg: #e06a94; --color-neg-bg: rgba(224, 106, 148, 0.18);
  }
}

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

body {
  background: var(--bg);
  color: var(--ink);
  font-family: var(--sans);
  -webkit-font-smoothing: antialiased;
}

a { color: inherit; }

.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 999;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 28px;
  background: color-mix(in srgb, var(--bg) 92%, transparent);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--line);
}

.brand { display: flex; align-items: center; gap: 10px; text-decoration: none; }
.brand-mark { width: 34px; height: 34px; flex: 0 0 auto; }
.brand-word { font-family: var(--serif); font-weight: 700; font-size: 1.05rem; letter-spacing: 0.01em; color: var(--ink); }
.brand-word b { color: var(--accent); }

.nav-links { position: absolute; left: 50%; transform: translateX(-50%); display: flex; align-items: center; gap: 4px; }
.nav-links > a {
  font-family: var(--mono); font-size: 0.76rem; font-weight: 700; text-transform: uppercase;
  letter-spacing: 0.04em; text-decoration: none; padding: 9px 14px; border-radius: 8px;
  color: var(--ink-soft); transition: background 0.15s ease, color 0.15s ease;
}
.nav-links > a:hover { background: var(--surface-2); color: var(--ink); }

.nav-toggle { display: none; flex-direction: column; gap: 4px; background: none; border: none; cursor: pointer; padding: 8px; }
.nav-toggle span { width: 22px; height: 2px; background: var(--ink); border-radius: 2px; transition: transform 0.2s ease, opacity 0.2s ease; }

@media (max-width: 860px) {
  .nav-links {
    position: fixed; inset: 60px 0 auto 0; background: var(--surface);
    flex-direction: column; align-items: stretch; padding: 10px;
    border-bottom: 1px solid var(--line); box-shadow: var(--shadow-md);
    transform: translateY(-8px); opacity: 0; visibility: hidden;
    transition: opacity 0.18s ease, transform 0.18s ease, visibility 0.18s; gap: 2px;
  }
  .nav-links.open { transform: translateY(0); opacity: 1; visibility: visible; }
  .nav-links > a { width: 100%; }
  .nav-toggle { display: flex; }
}

.quiz-page {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 100px 20px 48px;
}

.diagnostic-test-container { width: 100%; max-width: 640px; }

.diagnostic-card { background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); padding: 40px; box-shadow: var(--shadow-sm); }
.diagnostic-header { text-align: center; margin-bottom: 26px; }
.diagnostic-badge { display: inline-block; font-family: var(--mono); padding: 5px 14px; border-radius: 999px; background: var(--color-acc-bg); color: var(--color-acc); font-weight: 700; font-size: 0.7rem; letter-spacing: 0.05em; text-transform: uppercase; margin-bottom: 12px; }
.diagnostic-header h1 { font-family: var(--serif); font-size: 1.7rem; font-weight: 500; margin-bottom: 8px; color: var(--ink); }
.diagnostic-header p { color: var(--ink-soft); font-size: 0.95rem; line-height: 1.6; max-width: 620px; margin: 0 auto; }

.diagnostic-quiz-box { border: 1px solid var(--line); border-radius: 12px; padding: 26px; }
.quiz-status-row { display: flex; align-items: center; gap: 14px; margin-bottom: 18px; }
.quiz-tracker { font-family: var(--mono); font-size: 0.7rem; font-weight: 700; text-transform: uppercase; letter-spacing: 0.04em; color: var(--ink-faint); white-space: nowrap; }
.diag-progress-bar { flex: 1; height: 6px; background: var(--line); border-radius: 999px; overflow: hidden; }
.diag-progress-fill { height: 100%; width: 5%; background: linear-gradient(90deg, var(--accent), var(--accent-2)); transition: width 0.35s ease; }

.diag-passage-box {
  background: var(--surface-2);
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 16px 18px;
  margin-bottom: 20px;
}
.diag-passage-text { font-family: var(--serif); font-size: 0.98rem; line-height: 1.7; color: var(--ink); }

.diag-subquestions { margin-bottom: 20px; }

.diag-subq-tracker { display: block; font-family: var(--mono); font-size: 0.68rem; font-weight: 700; text-transform: uppercase; letter-spacing: 0.05em; color: var(--ink-faint); margin-bottom: 10px; }

.diag-question-prompt { font-size: 1rem; font-weight: 500; color: var(--ink); line-height: 1.6; margin-bottom: 14px; }

.diag-options { display: flex; flex-direction: column; gap: 8px; }

.diag-option-btn {
  text-align: left;
  padding: 12px 16px;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: var(--surface);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 0.92rem;
  cursor: pointer;
  transition: border-color 0.15s ease, background-color 0.15s ease, transform 0.1s ease;
}
.diag-option-btn:hover { border-color: var(--accent); background: var(--surface-2); }
.diag-option-btn:active { transform: scale(0.98); }
.diag-option-btn.is-selected { border-color: var(--accent); background: var(--accent-soft); font-weight: 600; }

.diag-options.is-locked .diag-option-btn { pointer-events: none; }
.diag-options.is-locked .diag-option-btn:not(.is-selected) { opacity: 0.5; }

.result-display-node { text-align: center; animation: resultIn 0.4s ease; }
@keyframes resultIn { from { opacity: 0; transform: translateY(10px); } to { opacity: 1; transform: translateY(0); } }
.result-medal-wrap { font-size: 3.2rem; margin-bottom: 10px; }
.result-display-node h3 { font-family: var(--serif); font-size: 1.4rem; font-weight: 500; margin-bottom: 8px; color: var(--ink); }
.result-display-node p { color: var(--ink-soft); font-size: 0.92rem; margin-bottom: 22px; }

.tier-placement-link {
  display: inline-flex; flex-direction: column; align-items: center; gap: 6px; text-decoration: none;
  background: var(--surface-2); border: 1px solid var(--line); border-radius: 16px; padding: 22px 40px;
  transition: transform 0.15s ease, box-shadow 0.15s ease, border-color 0.15s ease;
}
.tier-placement-link:hover { transform: translateY(-3px); box-shadow: var(--shadow-md); border-color: var(--accent); }
.tier-placement-link:active { transform: translateY(0); }

.tier-large-label { font-family: var(--serif); font-size: 2.6rem; font-weight: 500; color: var(--accent); }
.tier-sub-action { font-size: 0.85rem; font-weight: 700; color: var(--ink-soft); }

.signup-card {
  margin-top: 22px;
  padding: 22px;
  border: 1px solid var(--line);
  border-radius: 16px;
  background: var(--surface-2);
  text-align: left;
}
.signup-note { font-size: 0.92rem; font-weight: 600; color: var(--ink); margin-bottom: 14px; text-align: center; }

.signup-form-label { display: block; font-family: var(--mono); font-size: 0.68rem; font-weight: 700; text-transform: uppercase; letter-spacing: 0.04em; color: var(--ink-faint); margin-bottom: 6px; }
.signup-form-row { display: flex; gap: 10px; }
.signup-form-input {
  flex: 1;
  min-width: 0;
  padding: 11px 14px;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: var(--surface);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 0.9rem;
}
.signup-form-input:focus { outline: none; border-color: var(--accent); }
.signup-form-input.is-invalid { border-color: var(--bad); }

.signup-submit-btn {
  padding: 11px 20px;
  border: none;
  border-radius: 10px;
  background: var(--accent);
  color: #fff;
  font-family: var(--sans);
  font-size: 0.88rem;
  font-weight: 700;
  cursor: pointer;
  white-space: nowrap;
  transition: background-color 0.15s ease, transform 0.1s ease;
}
.signup-submit-btn:hover { background: var(--accent-2); }
.signup-submit-btn:active { transform: scale(0.98); }
.signup-submit-btn:disabled { opacity: 0.6; cursor: default; }

.signup-form-status { font-size: 0.82rem; margin-top: 10px; min-height: 1.1em; }
.signup-form-status.is-success { color: var(--good); }
.signup-form-status.is-error { color: var(--bad); }

@media (max-width: 480px) {
  .signup-form-row { flex-direction: column; }
}

@media (max-width: 560px) {
  .diagnostic-card { padding: 22px; }
}