:root {
  --ink: #030711; --panel: #07111d; --text: #f4fbff; --muted: #9eb7ca;
  --line: rgba(108, 202, 255, .24); --blue: #08a7ff; --blue-hot: #66ddff;
  --blue-deep: #004f9f; --danger: #ff6f7d; --success: #74e4b0;
}
html { min-height: 100%; scroll-behavior: smooth; }
body {
  min-height: 100vh; margin: 0; color: var(--text);
  background: radial-gradient(circle at 82% 12%, rgba(8,167,255,.18), transparent 34rem), linear-gradient(180deg,#02040a 0%,var(--ink) 44%,#050a12 100%);
  font-family: "Segoe UI",system-ui,-apple-system,BlinkMacSystemFont,sans-serif;
}
a { color: var(--blue-hot); text-decoration: none; }
a:hover { color: var(--text); }
.container { max-width: 1160px; }
.site-header { position: sticky; top: 0; z-index: 10; border-bottom: 1px solid rgba(102,221,255,.16); background: rgba(3,7,17,.82); backdrop-filter: blur(18px); }
.site-nav { min-height: 76px; }
.brand-mark { display: inline-flex; align-items: center; gap: .75rem; color: var(--text); font-weight: 700; }
.brand-mark:hover { color: var(--text); }
.brand-sigil { display: inline-grid; width: 2.35rem; height: 2.35rem; place-items: center; border: 1px solid rgba(102,221,255,.6); border-radius: 8px; background: linear-gradient(145deg,rgba(8,167,255,.24),rgba(1,14,27,.92)); box-shadow: 0 0 24px rgba(8,167,255,.36),inset 0 0 18px rgba(102,221,255,.18); }
.navbar-toggler { border-color: rgba(102,221,255,.35); }
.navbar-toggler:focus { box-shadow: 0 0 0 .2rem rgba(8,167,255,.24); }
.navbar-toggler-icon { filter: invert(1); }
.site-links { align-items: center; gap: .35rem; }
.site-links .nav-link { color: var(--muted); padding: .6rem .85rem; font-size: .95rem; }
.site-links .nav-link:hover,.site-links .nav-link:focus { color: var(--text); }
.srs-main { min-height: calc(100vh - 150px); padding-top: 48px; padding-bottom: 72px; }
.jp { font-family: "Yu Gothic","Meiryo","Noto Sans JP",sans-serif; }
h1,h2,h3 { color: var(--text); }
.text-body-secondary,.text-muted { color: var(--muted) !important; }
.p-5.bg-body-tertiary,.card,.stat-card,.study-card,.auth-card { border: 1px solid var(--line) !important; border-radius: 8px !important; background: radial-gradient(circle at 100% 0%,rgba(8,167,255,.13),transparent 16rem),linear-gradient(180deg,rgba(10,24,41,.88),rgba(5,10,18,.92)) !important; box-shadow: inset 0 1px 0 rgba(255,255,255,.04); color: #d9f5ff; }
.auth-card { max-width: 520px; margin: 0 auto; padding: 32px; }
.auth-card h1 { margin: 0; font-size: clamp(2rem,4vw,3.25rem); line-height: 1.05; }
.auth-muted { color: var(--muted); line-height: 1.65; margin: .6rem 0 1.5rem; }
.eyebrow { margin: 0 0 .65rem; color: var(--blue-hot); font-size: .78rem; font-weight: 700; letter-spacing: .16rem; text-transform: uppercase; }
.auth-divider { align-items: center; color: var(--muted); display: flex; gap: 12px; margin: 22px 0; font-size: .82rem; text-transform: uppercase; }
.auth-divider::before,.auth-divider::after { background: var(--line); content: ""; flex: 1; height: 1px; }
.auth-switch { color: var(--muted); margin: 22px 0 0; text-align: center; }
.stat-card { padding: 1.25rem; height: 100%; }
.stat-card strong { display: block; color: var(--text); font-size: 2rem; line-height: 1.1; }
.stat-card span { display: block; color: var(--muted); margin-top: .35rem; }
.study-card { max-width: 680px; padding: 2rem; margin-top: 4rem; box-shadow: 0 0 38px rgba(8,167,255,.12); }
.study-kanji { font-size: clamp(4rem,13vw,8rem); line-height: 1.1; }
.table { --bs-table-bg: transparent; --bs-table-color: #d9f5ff; --bs-table-border-color: var(--line); }
.table > :not(caption) > * > * { background-color: transparent; color: inherit; }
.table-success { --bs-table-color: #d5ffe9; --bs-table-bg: rgba(21,94,65,.3); }
.form-label,.form-check-label { color: #e9fbff; }
.form-control,.form-select { border-color: rgba(102,221,255,.26); background-color: rgba(2,8,15,.72); color: var(--text); }
.form-control:focus,.form-select:focus { border-color: rgba(102,221,255,.72); background-color: rgba(2,8,15,.88); color: var(--text); box-shadow: 0 0 0 .2rem rgba(8,167,255,.24); }
.form-control::placeholder { color: rgba(158,183,202,.72); }
.form-select option { background: var(--panel); color: var(--text); }
.btn-primary { border: 1px solid rgba(102,221,255,.72); border-radius: 8px; background: linear-gradient(135deg,var(--blue),var(--blue-deep)); color: var(--text); box-shadow: 0 0 28px rgba(8,167,255,.28); font-weight: 700; }
.btn-primary:hover,.btn-primary:focus { border-color: rgba(102,221,255,.9); color: var(--text); transform: translateY(-1px); }
.btn-outline-primary,.btn-outline-secondary,.btn-outline-success { border-color: rgba(102,221,255,.46); border-radius: 8px; color: var(--text); }
.btn-outline-primary:hover,.btn-outline-secondary:hover,.btn-outline-success:hover { border-color: rgba(102,221,255,.72); background: rgba(8,167,255,.18); color: var(--text); }
.alert-info { border-color: var(--line); background: rgba(8,167,255,.12); color: #d9f5ff; }
.alert-success { border-color: rgba(116,228,176,.42); background: rgba(21,94,65,.34); color: #d5ffe9; }
.alert-danger,.text-danger { color: #ffd5da !important; }
.alert-danger { border-color: rgba(255,111,125,.48); background: rgba(108,25,38,.34); }
.site-footer { border-top: 1px solid rgba(102,221,255,.18); padding: 1.4rem 0; color: var(--muted); background: #02040a; }
.site-footer .container { display: flex; flex-wrap: wrap; justify-content: space-between; gap: 1rem; }
.sso-login-link { margin: -2rem auto 2rem; max-width: 420px; text-align: center; font-size: .9rem; }
.sso-login-link a { color: var(--muted); }
.sso-login-link a:hover { color: var(--blue-hot); }
@media (max-width:575.98px) { .srs-main { padding-top: 28px; } .p-5.bg-body-tertiary,.study-card,.auth-card { padding: 24px !important; } }