:root {
  --rail-primary: #0ea5e9;
  --rail-primary-dark: #2563eb;
  --rail-navy: #0f172a;
  --rail-bg: #f8fafc;
  --rail-surface: #ffffff;
  --rail-text: #0f172a;
  --rail-text-muted: #64748b;
  --rail-border: #e2e8f0;
  --rail-success: #16a34a;
  --rail-danger: #dc2626;
  --rail-warning: #f59e0b;
  --rail-radius-sm: 8px;
  --rail-radius: 12px;
  --rail-radius-lg: 16px;
}

html { font-size: 16px; }
body { background: var(--rail-bg); color: var(--rail-text); font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif; }
a { color: var(--rail-primary-dark); }
a:focus-visible, button:focus-visible, input:focus-visible { outline: 3px solid rgba(14, 165, 233, .35); outline-offset: 2px; }
.rail-navbar { background: var(--rail-surface); border-bottom: 1px solid var(--rail-border); }
.rail-brand { align-items: center; color: var(--rail-navy); display: flex; font-size: 1.05rem; font-weight: 700; gap: .6rem; letter-spacing: -.02em; }
.rail-brand:hover { color: var(--rail-navy); }
.rail-brand-mark { align-items: center; background: var(--rail-navy); border-radius: var(--rail-radius-sm); color: #fff; display: inline-flex; font-size: .8rem; height: 32px; justify-content: center; width: 32px; }
.rail-brand-muted { color: var(--rail-text-muted); font-weight: 400; }
.rail-navbar .nav-link { color: var(--rail-text-muted); font-size: .9rem; padding-left: .75rem; padding-right: .75rem; }
.rail-navbar .nav-link:hover, .rail-navbar .nav-link:focus { color: var(--rail-primary-dark); }
.rail-user-name { color: var(--rail-text-muted); font-size: .875rem; }
.btn { border-radius: var(--rail-radius-sm); font-weight: 600; min-height: 44px; padding: .6rem 1rem; }
.btn-primary { background: var(--rail-primary-dark); border-color: var(--rail-primary-dark); }
.btn-primary:hover, .btn-primary:focus { background: #1d4ed8; border-color: #1d4ed8; }
.btn-outline-primary { color: var(--rail-primary-dark); border-color: #bfdbfe; }
.btn-outline-secondary { color: var(--rail-text); border-color: var(--rail-border); }
.rail-google-button { cursor: pointer; transition: background-color .15s ease, border-color .15s ease, color .15s ease, transform .15s ease; }
.rail-google-button:hover, .rail-google-button:focus { background: var(--rail-text); border-color: var(--rail-text); color: #fff; }
.rail-google-button:hover { transform: translateY(-1px); }
.btn-secondary:disabled { background: #cbd5e1; border-color: #cbd5e1; color: #64748b; opacity: 1; }
.rail-hero { background: var(--rail-surface); border-bottom: 1px solid var(--rail-border); }
.rail-kicker, .rail-card-label { color: var(--rail-primary-dark); font-size: .75rem; font-weight: 700; letter-spacing: .08em; text-transform: uppercase; }
.rail-display { color: var(--rail-navy); font-size: clamp(2.2rem, 5vw, 3.6rem); font-weight: 700; letter-spacing: -.055em; line-height: 1.08; max-width: 700px; }
.rail-lead { color: var(--rail-text-muted); font-size: 1.05rem; line-height: 1.65; max-width: 540px; }
.rail-hero-card, .rail-card, .rail-auth-card, .rail-feature { background: var(--rail-surface); border: 1px solid var(--rail-border); border-radius: var(--rail-radius-lg); }
.rail-hero-card { padding: 1.5rem; }
.progress { background: #e0f2fe; border-radius: 999px; height: 9px; }
.progress-bar { background: var(--rail-primary); border-radius: inherit; }
.rail-feature { height: 100%; padding: 1.4rem; }
.rail-feature i { color: var(--rail-primary-dark); font-size: 1.5rem; }
.rail-feature h2 { font-size: 1.1rem; font-weight: 700; margin: 1rem 0 .5rem; }
.rail-feature p { color: var(--rail-text-muted); font-size: .9rem; line-height: 1.55; margin-bottom: 0; }
.rail-auth-page { align-items: flex-start; display: flex; justify-content: center; min-height: calc(100vh - 75px); padding: 3rem 1rem; }
.rail-auth-card { max-width: 440px; padding: 2rem; width: 100%; }
.rail-social-card { max-width: 460px; }
.rail-auth-icon { align-items: center; background: var(--rail-very-light, #eff6ff); border-radius: 50%; color: var(--rail-primary-dark); display: inline-flex; font-size: 1.25rem; height: 48px; justify-content: center; width: 48px; }
.rail-google-icon { background: #fef2f2; color: #dc2626; }
.rail-verification-card { max-width: 480px; padding: 2.5rem 2rem; }
.rail-success-icon { background: #dcfce7; color: var(--rail-success); }
.rail-warning-icon { background: #fef3c7; color: #b45309; }
.rail-verification-note { align-items: flex-start; background: var(--rail-bg); border: 1px solid var(--rail-border); border-radius: var(--rail-radius); color: var(--rail-text-muted); display: flex; font-size: .875rem; gap: .7rem; line-height: 1.5; padding: 1rem; }
.rail-verification-note i { color: var(--rail-primary-dark); flex: 0 0 auto; font-size: 1rem; margin-top: .1rem; }
.rail-auth-card form p { margin-bottom: 1rem; }
.rail-auth-card label { color: var(--rail-text); display: block; font-size: .875rem; font-weight: 600; margin-bottom: .45rem; }
.rail-auth-card input:not([type='checkbox']) { background: #fff; border: 1px solid var(--rail-border); border-radius: var(--rail-radius); display: block; min-height: 48px; padding: .7rem .85rem; width: 100%; }
.rail-auth-card input:not([type='checkbox']):focus { border-color: var(--rail-primary); box-shadow: 0 0 0 .2rem rgba(14, 165, 233, .12); outline: 0; }
.rail-auth-card .form-check { min-height: 24px; padding-left: 1.6rem; }
.rail-auth-card .form-check-label { color: var(--rail-text-muted); cursor: pointer; display: inline; font-size: .8rem; font-weight: 400; margin: 0; }
.rail-auth-card input[type='checkbox'] { appearance: none; background: #fff; border: 1px solid var(--rail-border); border-radius: 5px; cursor: pointer; display: inline-block; height: 18px; margin: 0 0 0 -1.6rem; min-height: 18px; padding: 0; position: relative; vertical-align: -4px; width: 18px; }
.rail-auth-card input[type='checkbox']:checked { background: var(--rail-primary-dark); border-color: var(--rail-primary-dark); }
.rail-auth-card input[type='checkbox']:checked::after { border: solid #fff; border-width: 0 2px 2px 0; content: ''; height: 9px; left: 5px; position: absolute; top: 2px; transform: rotate(45deg); width: 5px; }
.rail-auth-card ul.errorlist { color: var(--rail-danger); font-size: .8rem; list-style: none; margin: .35rem 0; padding: 0; }
.rail-auth-card .form-text { color: var(--rail-text-muted); font-size: .78rem; line-height: 1.45; margin-top: .45rem; }
.rail-auth-card .form-text ul { margin: .35rem 0 0; padding-left: 1.1rem; }
.rail-auth-card .form-text ul li + li { margin-top: .2rem; }
.rail-divider { align-items: center; color: var(--rail-text-muted); display: flex; gap: 1rem; margin: 1.5rem 0; }
.rail-divider::before, .rail-divider::after { background: var(--rail-border); content: ''; flex: 1; height: 1px; }
.rail-divider span { font-size: .8rem; }
.alert { border-radius: var(--rail-radius); }
.rail-card { padding: 1.5rem; }
.rail-card h2 { font-size: 1.2rem; font-weight: 700; }
.rail-card-title { color: var(--rail-text-muted); font-size: .8rem; font-weight: 600; text-transform: uppercase; }
.stat-value { font-size: 1.8rem; font-weight: 700; }
.setup-heading { border-left: 3px solid var(--rail-primary); padding-left: 1rem; }
.rail-setup-card { padding: 1.75rem; }
.rail-setup-form { display: grid; gap: 1.25rem; }
.rail-field-group > label { color: var(--rail-text); display: block; font-size: .9rem; font-weight: 600; margin-bottom: .5rem; }
.rail-select-wrap { position: relative; }
.rail-select-wrap::after { color: var(--rail-text-muted); content: '\F282'; font-family: 'bootstrap-icons'; font-size: .9rem; pointer-events: none; position: absolute; right: 1rem; top: 50%; transform: translateY(-50%); }
.rail-setup-form select { appearance: none; background-color: var(--rail-surface); border: 1px solid var(--rail-border); border-radius: var(--rail-radius); color: var(--rail-text); cursor: pointer; font-size: .95rem; min-height: 50px; padding: .7rem 2.75rem .7rem 1rem; transition: border-color .15s ease, box-shadow .15s ease; width: 100%; }
.rail-setup-form select:hover { border-color: #93c5fd; }
.rail-setup-form select:focus { border-color: var(--rail-primary); box-shadow: 0 0 0 .2rem rgba(14, 165, 233, .12); outline: 0; }
.rail-setup-form ul.errorlist { color: var(--rail-danger); font-size: .8rem; list-style: none; margin: .4rem 0 0; padding: 0; }
.rail-fallback-box { align-items: flex-start; background: var(--rail-bg); border: 1px solid #bfdbfe; border-radius: var(--rail-radius); display: flex; gap: .75rem; padding: 1rem; }
.rail-fallback-box input { accent-color: var(--rail-primary-dark); flex: 0 0 auto; height: 18px; margin-top: .2rem; width: 18px; }
.rail-fallback-box label { color: var(--rail-text); cursor: pointer; font-size: .9rem; font-weight: 600; }
.setup-submit { border-top: 1px solid var(--rail-border); margin-top: .25rem; padding-top: 1.5rem !important; }
.question-option { background: var(--rail-surface); border: 1px solid var(--rail-border); border-radius: var(--rail-radius); cursor: pointer; display: block; padding: 1rem; transition: border-color .15s ease, background-color .15s ease; }
.question-option:hover, .question-option.selected { background: var(--rail-bg); border-color: var(--rail-primary); }
.question-option input { margin-right: .75rem; }
.question-option.correct { background: #f0fdf4; border-color: #86efac; }
.question-option.incorrect { background: #fef2f2; border-color: #fca5a5; }
.exam-header { align-items: center; display: flex; justify-content: space-between; margin-bottom: 1rem; }
.exam-navigation { align-items: center; display: grid; grid-template-columns: 48px 1fr 48px; gap: 1rem; }
.exam-navigation > .btn { justify-self: center; }
.exam-arrow { align-items: center; background: var(--rail-surface); border: 1px solid var(--rail-border); border-radius: var(--rail-radius-sm); color: var(--rail-text); display: inline-flex; font-size: 1.2rem; height: 48px; justify-content: center; text-decoration: none; width: 48px; }
.exam-arrow:hover { background: var(--rail-bg); border-color: var(--rail-primary); color: var(--rail-primary-dark); }
.exam-arrow-placeholder { height: 48px; width: 48px; }
@media (max-width: 575.98px) { .rail-auth-page { padding: 2rem .75rem; } .rail-auth-card { padding: 1.5rem; } .rail-display { font-size: 2.35rem; } }
@media (max-width: 575.98px) { .exam-navigation { gap: .5rem; grid-template-columns: 42px 1fr 42px; } .exam-arrow, .exam-arrow-placeholder { height: 44px; width: 42px; } .exam-navigation > .btn { font-size: .8rem; padding-left: .7rem !important; padding-right: .7rem !important; } }
@media (prefers-reduced-motion: reduce) { *, *::before, *::after { scroll-behavior: auto !important; transition: none !important; } }