:root {
  font-family: Inter, "Hiragino Sans", "Yu Gothic", system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  color: #182033;
  background: #f5f7fb;
  font-synthesis: none;
}

* { box-sizing: border-box; }
body { margin: 0; min-height: 100vh; }
button, input, select, textarea { font: inherit; }
button { cursor: pointer; }

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  min-height: 64px;
  padding: 0 24px;
  background: rgba(255, 255, 255, 0.96);
  border-bottom: 1px solid #e3e7ef;
  backdrop-filter: blur(10px);
}

.brand { color: #2856b6; font-size: 1.25rem; font-weight: 800; text-decoration: none; }
.header-actions { display: flex; align-items: center; gap: 10px; }
.phase-badge { padding: 5px 10px; border: 1px solid #d8deea; border-radius: 999px; color: #556176; font-size: 0.8rem; font-weight: 700; }
.page-shell { width: min(100% - 32px, 1040px); margin: 0 auto; padding: 48px 0 80px; }
.hero { padding: 24px 0 36px; }
.eyebrow { margin: 0 0 8px; color: #3767c8; font-size: 0.82rem; font-weight: 800; letter-spacing: 0.08em; text-transform: uppercase; }
h1, h2, h3, p { margin-top: 0; }
h1 { max-width: 760px; margin-bottom: 14px; font-size: clamp(2rem, 7vw, 4rem); line-height: 1.05; }
h2 { margin-bottom: 8px; }
h3 { margin-bottom: 12px; }
.hero-copy { max-width: 720px; color: #59657b; font-size: 1.05rem; line-height: 1.8; }

.status { display: inline-flex; align-items: center; min-height: 32px; margin: 10px 0 0; padding: 5px 11px; border-radius: 999px; background: #e9edf5; color: #566177; font-size: 0.88rem; font-weight: 700; }
.status-ok { background: #e5f6ec; color: #17633b; }
.status-error { background: #fdeaea; color: #9c3030; }

.panel { display: grid; gap: 24px; margin-bottom: 20px; padding: 28px; border: 1px solid #e1e6ef; border-radius: 22px; background: #fff; box-shadow: 0 12px 32px rgba(32, 52, 89, 0.06); }
.dashboard { display: grid; gap: 20px; }
.form-stack { display: grid; gap: 16px; }
label { display: grid; gap: 7px; color: #33405a; font-size: 0.92rem; font-weight: 700; }
input, select, textarea { width: 100%; min-height: 46px; padding: 10px 12px; border: 1px solid #cfd7e5; border-radius: 11px; background: #fff; color: #182033; }
textarea { min-height: 108px; resize: vertical; line-height: 1.6; }
input:focus, select:focus, textarea:focus { outline: 3px solid rgba(55, 103, 200, 0.15); border-color: #3767c8; }
.field-help { color: #778297; font-size: 0.78rem; font-weight: 500; line-height: 1.5; }
.button { min-height: 44px; padding: 10px 16px; border: 0; border-radius: 11px; background: #3767c8; color: #fff; font-weight: 800; }
.button:hover { background: #2d58ad; }
.button:disabled { cursor: not-allowed; opacity: 0.55; }
.button-danger { background: #b33c3c; }
.button-danger:hover { background: #942e2e; }
.button-quiet { background: transparent; color: #34415b; border: 1px solid #d4dbe8; }
.button-small { min-height: 34px; padding: 6px 10px; font-size: 0.82rem; }
.muted { margin-bottom: 0; color: #6a7589; line-height: 1.7; }
.warning { margin-bottom: 0; color: #714f15; line-height: 1.6; }
.form-error { margin-bottom: 0; color: #a52f2f; font-weight: 700; }
.section-heading { display: flex; align-items: start; justify-content: space-between; gap: 16px; }
.account-label { margin: 0; color: #59657b; font-size: 0.9rem; font-weight: 700; }
.classroom-context { display: flex; align-items: center; justify-content: space-between; gap: 16px; margin-bottom: 20px; padding: 16px 20px; border: 1px solid #d9e2f2; border-radius: 16px; background: #f8fbff; }
.classroom-context-label { margin: 0 0 3px; color: #66738a; font-size: 0.78rem; font-weight: 700; }
.classroom-context-name { margin: 0; color: #20345d; font-size: 1rem; font-weight: 800; }
.card-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(210px, 1fr)); gap: 12px; }
.group-card { padding: 18px; border: 1px solid #dfe5ef; border-radius: 15px; background: #f9fbff; }
.group-card h3 { margin-bottom: 6px; }
.role-badge { display: inline-block; padding: 3px 8px; border-radius: 999px; background: #edf2fc; color: #315cac; font-size: 0.78rem; font-weight: 800; }
.teacher-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 16px; }
.subpanel { padding: 20px; border: 1px solid #e2e7ef; border-radius: 16px; background: #fafbfe; }
.credential-card { padding: 20px; border: 1px solid #ead9a7; border-radius: 16px; background: #fff9e9; }
.credential-card code { user-select: all; font-size: 1rem; }
.members-section { display: grid; gap: 14px; }
.members-section .section-heading select { width: min(280px, 100%); }
.members-list { display: grid; gap: 10px; }
.member-row { display: grid; grid-template-columns: minmax(0, 1fr) auto; gap: 12px; align-items: center; padding: 14px 16px; border: 1px solid #e1e6ef; border-radius: 13px; }
.member-main { min-width: 0; }
.member-id { margin: 0 0 5px; overflow-wrap: anywhere; font-weight: 800; }
.member-meta { margin: 0; color: #6a7589; font-size: 0.85rem; }
.member-actions { display: flex; flex-wrap: wrap; justify-content: flex-end; gap: 8px; }
.phase2-description { margin: 9px 0 0; color: #3f4c63; font-size: 0.9rem; line-height: 1.65; white-space: pre-wrap; }
.hidden { display: none !important; }

@media (max-width: 720px) {
  .site-header { padding: 0 16px; }
  .page-shell { width: min(100% - 24px, 1040px); padding-top: 28px; }
  .panel { padding: 20px; }
  .classroom-context { align-items: stretch; flex-direction: column; }
  .classroom-context .button { width: 100%; }
  .teacher-grid { grid-template-columns: 1fr; }
  .section-heading { display: grid; }
  .members-section .section-heading select { width: 100%; }
  .member-row { grid-template-columns: 1fr; }
  .member-actions { justify-content: flex-start; }
}