/* ── Design tokens ───────────────────────────────────────────────────────── */
:root {
  --bg:          #f4f6f9;
  --surface:     #ffffff;
  --surface-2:   #f8fafc;
  --border:      #e2e8f0;
  --text:        #0f172a;
  --text-2:      #64748b;
  --text-3:      #94a3b8;
  --nav-bg:      rgba(255,255,255,.88);
  --green:       #16884a;
  --green-dk:    #0a5c32;
  --green-light: #dcfce7;
  --green-glow:  rgba(22,136,74,.14);
  --red:         #dc2626;
  --red-light:   #fee2e2;
  --shadow-sm:   0 1px 2px rgba(0,0,0,.05);
  --shadow:      0 1px 3px rgba(0,0,0,.06), 0 4px 16px rgba(0,0,0,.07);
  --shadow-lg:   0 4px 8px rgba(0,0,0,.07), 0 12px 32px rgba(0,0,0,.11);
  --radius:      16px;
  --t:           .25s cubic-bezier(.4,0,.2,1);
}

[data-theme="dark"] {
  --bg:          #0b0f19;
  --surface:     #131929;
  --surface-2:   #1a2133;
  --border:      #232d42;
  --text:        #e2e8f0;
  --text-2:      #8896b3;
  --text-3:      #4a5568;
  --nav-bg:      rgba(13,20,38,.9);
  --green:       #34d399;
  --green-dk:    #6ee7b7;
  --green-light: #052e16;
  --green-glow:  rgba(52,211,153,.13);
  --red:         #f87171;
  --red-light:   #450a0a;
  --shadow-sm:   0 1px 2px rgba(0,0,0,.3);
  --shadow:      0 1px 3px rgba(0,0,0,.4), 0 4px 16px rgba(0,0,0,.4);
  --shadow-lg:   0 4px 8px rgba(0,0,0,.4), 0 12px 32px rgba(0,0,0,.6);
}

/* ── Reset ───────────────────────────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
[hidden] { display: none !important; }
html { scroll-behavior: smooth; }

body {
  font-family: 'Inter', system-ui, sans-serif;
  background: var(--bg); color: var(--text);
  min-height: 100vh; display: flex; flex-direction: column; align-items: center;
  transition: background var(--t), color var(--t);
}

/* ── Navbar ──────────────────────────────────────────────────────────────── */
nav {
  position: sticky; top: 0; z-index: 100; width: 100%;
  background: var(--nav-bg); backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--border); height: 56px;
  display: flex; align-items: center; justify-content: space-between;
  padding: 0 2rem;
  transition: background var(--t), border-color var(--t);
}

.nav-brand {
  display: flex; align-items: center; gap: .5rem;
  text-decoration: none; color: var(--text);
  font-weight: 800; font-size: 1.05rem; letter-spacing: -.03em;
}

.brand-mark {
  width: 30px; height: 30px;
  background: linear-gradient(135deg, var(--green) 0%, var(--green-dk) 100%);
  border-radius: 8px; display: flex; align-items: center; justify-content: center;
  font-size: .9rem; flex-shrink: 0; box-shadow: 0 2px 8px var(--green-glow);
}
.brand-mark.sm { width: 24px; height: 24px; font-size: .75rem; border-radius: 6px; }

.nav-sep  { color: var(--text-3); font-weight: 400; }
.nav-page { color: var(--text-2); font-weight: 600; font-size: .95rem; }

.nav-right { display: flex; align-items: center; gap: .75rem; }

.nav-link {
  font-size: .85rem; font-weight: 500; color: var(--text-2);
  text-decoration: none; transition: color var(--t);
}
.nav-link:hover { color: var(--text); }

.theme-btn {
  width: 36px; height: 36px; border-radius: 8px;
  border: 1px solid var(--border); background: var(--surface);
  cursor: pointer; font-size: 1rem;
  display: flex; align-items: center; justify-content: center;
  transition: background var(--t), border-color var(--t), transform .15s;
}
.theme-btn:hover { transform: scale(1.08); }

/* ── Main layout ─────────────────────────────────────────────────────────── */
main {
  width: 100%; max-width: 720px;
  padding: 2.5rem 1.25rem 4rem;
  display: flex; flex-direction: column; gap: 2rem;
  flex: 1;
}

/* ── Unofficial notice ───────────────────────────────────────────────────── */
.unofficial-notice {
  display: flex; align-items: flex-start; gap: .6rem;
  background: #fefce8; border: 1px solid #fde047; border-radius: 10px;
  padding: .75rem 1rem; font-size: .82rem; color: #713f12; line-height: 1.5;
}
[data-theme="dark"] .unofficial-notice {
  background: #1c1505; border-color: #854d0e; color: #fde68a;
}
.unofficial-notice svg { flex-shrink: 0; margin-top: .15rem; color: #ca8a04; }
[data-theme="dark"] .unofficial-notice svg { color: #fbbf24; }
.unofficial-notice a { color: inherit; font-weight: 600; }

/* ── Hero ────────────────────────────────────────────────────────────────── */
.hero { text-align: center; }
.hero h1 {
  font-size: clamp(1.75rem, 4.5vw, 2.6rem);
  font-weight: 800; letter-spacing: -.04em; line-height: 1.15;
  margin-bottom: .75rem;
}
.hero-sub { font-size: 1rem; color: var(--text-2); line-height: 1.6; }

/* ── Stats bar ───────────────────────────────────────────────────────────── */
.stats-bar {
  display: grid; grid-template-columns: repeat(3, 1fr);
  border: 1px solid var(--border); border-radius: var(--radius);
  overflow: hidden; background: var(--border); gap: 1px;
  box-shadow: var(--shadow-sm);
}
.stat-block {
  background: var(--surface); padding: 1.1rem;
  display: flex; flex-direction: column; align-items: center; gap: .25rem;
}
.stat-num {
  font-size: 1.6rem; font-weight: 800; letter-spacing: -.04em;
  color: var(--text);
}
.stat-num.green { color: var(--green); }
.stat-num.red   { color: var(--red); }
.stat-lbl { font-size: .72rem; color: var(--text-3); font-weight: 500; }

/* ── Card ────────────────────────────────────────────────────────────────── */
.card {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 1.75rem;
  box-shadow: var(--shadow);
}
.card-title {
  font-size: 1.1rem; font-weight: 700; letter-spacing: -.02em;
  margin-bottom: 1.5rem; color: var(--text);
}

/* ── Form ────────────────────────────────────────────────────────────────── */
.form-row { display: flex; flex-direction: column; gap: 1rem; margin-bottom: 1rem; }
.form-row.two-col { flex-direction: row; }
@media (max-width: 520px) { .form-row.two-col { flex-direction: column; } }

.form-group { display: flex; flex-direction: column; gap: .4rem; flex: 1; }

label {
  font-size: .8rem; font-weight: 600; color: var(--text-2);
  letter-spacing: .02em; text-transform: uppercase;
}
.label-hint { font-size: .75rem; font-weight: 400; letter-spacing: 0; text-transform: none; color: var(--text-3); }

input, select {
  background: var(--surface-2); border: 1px solid var(--border);
  border-radius: 10px; padding: .65rem .85rem;
  font-size: .9rem; color: var(--text); font-family: inherit;
  transition: border-color var(--t), box-shadow var(--t);
  width: 100%;
}
input:focus, select:focus {
  outline: none; border-color: var(--green);
  box-shadow: 0 0 0 3px var(--green-glow);
}
input::placeholder { color: var(--text-3); }
select { cursor: pointer; }

/* ── CAPTCHA ─────────────────────────────────────────────────────────────── */
.captcha-row { flex-direction: row; align-items: flex-end; gap: 1rem; }
@media (max-width: 520px) { .captcha-row { flex-direction: column; } }

.captcha-group { flex: 1.5; }

.captcha-box {
  display: flex; align-items: center; gap: .6rem; margin-top: .1rem;
}

.captcha-img-wrap {
  position: relative;
  height: 44px; min-width: 120px;
  border: 1px solid var(--border); border-radius: 8px;
  overflow: hidden; background: var(--surface-2);
  display: flex; align-items: center; justify-content: center;
}

#captchaImg {
  height: 44px; width: auto; display: block;
}

.captcha-loading {
  position: absolute; inset: 0;
  display: flex; align-items: center; justify-content: center;
  font-size: .75rem; color: var(--text-3);
  background: var(--surface-2);
}

.captcha-refresh {
  width: 36px; height: 36px; flex-shrink: 0;
  border: 1px solid var(--border); border-radius: 8px;
  background: var(--surface); cursor: pointer;
  font-size: 1.1rem; color: var(--text-2);
  display: flex; align-items: center; justify-content: center;
  transition: color var(--t), border-color var(--t), transform .15s;
}
.captcha-refresh:hover { color: var(--green); border-color: var(--green); transform: rotate(90deg); }

/* ── Submit button ───────────────────────────────────────────────────────── */
.submit-btn {
  width: 100%; padding: .9rem; margin-top: .5rem;
  background: linear-gradient(135deg, var(--green) 0%, var(--green-dk) 100%);
  color: #fff; border: none; border-radius: 12px;
  font-size: 1rem; font-weight: 700; cursor: pointer;
  display: flex; align-items: center; justify-content: center; gap: .6rem;
  box-shadow: 0 2px 12px var(--green-glow);
  transition: opacity var(--t), transform .15s, box-shadow var(--t);
}
.submit-btn:hover  { transform: translateY(-1px); box-shadow: 0 6px 20px var(--green-glow); }
.submit-btn:active { transform: translateY(0); }
.submit-btn:disabled { opacity: .45; cursor: not-allowed; transform: none; box-shadow: none; }

.btn-spinner {
  width: 18px; height: 18px; flex-shrink: 0; border-radius: 50%;
  border: 2.5px solid rgba(255,255,255,.35); border-top-color: #fff;
  animation: spin .7s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }

/* ── Error message ───────────────────────────────────────────────────────── */
.error-msg {
  background: var(--red-light); color: var(--red);
  border: 1px solid color-mix(in srgb, var(--red) 30%, transparent);
  border-radius: 10px; padding: .75rem 1rem;
  font-size: .875rem; margin-bottom: .5rem;
}

/* ── Result card ─────────────────────────────────────────────────────────── */
.result-card { animation: slideDown .3s ease; }

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

.result-header {
  display: flex; align-items: center; justify-content: space-between;
  flex-wrap: wrap; gap: .75rem; margin-bottom: 1.5rem;
}

.result-name {
  font-size: 1.3rem; font-weight: 800; letter-spacing: -.03em; color: var(--text);
}
.result-meta { font-size: .85rem; color: var(--text-2); margin-top: .25rem; }

.result-badge {
  padding: .4rem 1rem; border-radius: 99px;
  font-size: .85rem; font-weight: 700; letter-spacing: .02em;
  flex-shrink: 0;
}
.result-badge.pass { background: var(--green-light); color: var(--green); }
.result-badge.fail { background: var(--red-light); color: var(--red); }

.info-grid {
  display: grid; grid-template-columns: repeat(2, 1fr);
  gap: .5rem; margin-bottom: 1.5rem;
}
@media (max-width: 460px) { .info-grid { grid-template-columns: 1fr; } }

.info-item {
  background: var(--surface-2); border: 1px solid var(--border);
  border-radius: 10px; padding: .6rem .85rem;
}
.info-label { font-size: .7rem; font-weight: 600; color: var(--text-3); text-transform: uppercase; letter-spacing: .05em; }
.info-value { font-size: .9rem; font-weight: 600; color: var(--text); margin-top: .15rem; }

.grades-title {
  font-size: .8rem; font-weight: 700; color: var(--text-2);
  text-transform: uppercase; letter-spacing: .06em; margin-bottom: .75rem;
}

.grades-table {
  width: 100%; border-collapse: collapse; font-size: .875rem;
}
.grades-table th {
  text-align: left; padding: .5rem .75rem;
  font-size: .7rem; font-weight: 700; color: var(--text-3);
  text-transform: uppercase; letter-spacing: .06em;
  border-bottom: 2px solid var(--border);
}
.grades-table td {
  padding: .55rem .75rem; border-bottom: 1px solid var(--border);
  color: var(--text);
}
.grades-table tr:last-child td { border-bottom: none; }
.grades-table tr:hover td { background: var(--surface-2); }

.grade-chip {
  display: inline-block; padding: .15rem .55rem;
  border-radius: 6px; font-weight: 700; font-size: .8rem;
}
.grade-A\+ { background: #dcfce7; color: #15803d; }
.grade-A   { background: #d1fae5; color: #065f46; }
.grade-A\-  { background: #d1fae5; color: #065f46; }
.grade-B   { background: #dbeafe; color: #1e40af; }
.grade-C   { background: #fef9c3; color: #854d0e; }
.grade-D   { background: #ffedd5; color: #9a3412; }
.grade-F   { background: #fee2e2; color: #991b1b; }

[data-theme="dark"] .grade-A\+ { background: #052e16; color: #6ee7b7; }
[data-theme="dark"] .grade-A   { background: #052e16; color: #6ee7b7; }
[data-theme="dark"] .grade-B   { background: #1e3a5f; color: #93c5fd; }
[data-theme="dark"] .grade-C   { background: #451a03; color: #fde68a; }
[data-theme="dark"] .grade-D   { background: #431407; color: #fdba74; }
[data-theme="dark"] .grade-F   { background: #450a0a; color: #fca5a5; }

/* ── FAQ ─────────────────────────────────────────────────────────────────── */
.section-title { font-size: 1.2rem; font-weight: 800; letter-spacing: -.03em; margin-bottom: 1rem; }
.faq-list { display: flex; flex-direction: column; gap: .5rem; }

.faq-item {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: 12px; overflow: hidden; box-shadow: var(--shadow-sm);
}
.faq-item[open] { box-shadow: var(--shadow); }
.faq-item summary {
  padding: 1rem 1.25rem; font-weight: 600; font-size: .9rem;
  cursor: pointer; list-style: none;
  display: flex; justify-content: space-between; align-items: center;
  user-select: none;
}
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::after { content: '+'; font-size: 1.2rem; font-weight: 400; color: var(--text-3); }
.faq-item[open] summary::after { content: '−'; }
.faq-item p { padding: 0 1.25rem 1rem; font-size: .875rem; color: var(--text-2); line-height: 1.6; }

/* ── Footer ──────────────────────────────────────────────────────────────── */
footer {
  width: 100%; border-top: 1px solid var(--border); background: var(--surface);
  padding: 1.5rem 2rem; transition: background var(--t), border-color var(--t);
}
.footer-inner {
  max-width: 720px; margin: 0 auto;
  display: flex; align-items: center; gap: 1.5rem; flex-wrap: wrap;
}
.footer-brand {
  display: flex; align-items: center; gap: .4rem;
  text-decoration: none; color: var(--text); font-weight: 800; font-size: .9rem;
}
.footer-links { display: flex; gap: 1.25rem; flex-wrap: wrap; }
.footer-links a { color: var(--text-2); font-size: .85rem; text-decoration: none; transition: color var(--t); }
.footer-links a:hover { color: var(--text); }
.footer-note { width: 100%; font-size: .78rem; color: var(--text-3); font-style: italic; }
.footer-copy { width: 100%; font-size: .8rem; color: var(--text-3); }
.footer-copy a { color: var(--text-3); text-decoration: underline; }

/* ── Cookie banner ───────────────────────────────────────────────────────── */
.cookie-banner {
  position: fixed; bottom: 0; left: 0; right: 0; z-index: 200;
  background: var(--surface); border-top: 1px solid var(--border);
  padding: 1rem 2rem;
  display: flex; align-items: center; gap: 1.5rem; flex-wrap: wrap;
  box-shadow: 0 -4px 24px rgba(0,0,0,.1);
}
.cookie-banner p { font-size: .875rem; color: var(--text-2); flex: 1; min-width: 200px; }
.cookie-banner a { color: var(--green); }
.cookie-actions { display: flex; gap: .75rem; flex-shrink: 0; }
.cookie-btn {
  padding: .45rem 1.1rem; border-radius: 8px;
  font-size: .85rem; font-weight: 600; cursor: pointer;
  transition: opacity var(--t), transform .15s;
}
.cookie-btn:hover { opacity: .85; transform: scale(1.03); }
.cookie-btn.outline { background: transparent; border: 1px solid var(--border); color: var(--text-2); }
.cookie-btn.solid   { background: var(--green); color: #fff; border: none; }