/* ============================================================
   認證頁面樣式 auth.css
   登入 / 註冊 / 忘記密碼
   ============================================================ */

/* ── 全頁背景 ─────────────────────────────────────────────── */
.auth-page {
  min-height: 100vh;
  display: flex;
  align-items: flex-start;
  justify-content: center;
  padding: 40px 16px 40px;
  position: relative;
  overflow-x: hidden;
  background: #F0F5FF;
}

/* 幾何裝飾背景 */
.auth-page::before {
  content: '';
  position: fixed;
  inset: 0;
  background:
    radial-gradient(ellipse 70% 55% at 15% 5%,  rgba(59,125,216,.14) 0%, transparent 65%),
    radial-gradient(ellipse 55% 65% at 85% 95%, rgba(91,159,232,.11) 0%, transparent 60%),
    radial-gradient(ellipse 40% 40% at 75% 20%, rgba(39,174,96,.07)  0%, transparent 55%),
    linear-gradient(170deg, #EBF3FF 0%, #F4F6FA 50%, #EEF7F0 100%);
  z-index: 0;
}

/* ── 容器 ─────────────────────────────────────────────────── */
.auth-wrap {
  width: 100%;
  max-width: 460px;
  position: relative;
  z-index: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0;
  animation: authIn .45s cubic-bezier(.22,.68,0,1.2) both;
}
.auth-wrap.wide { max-width: 520px; }

@keyframes authIn {
  from { opacity: 0; transform: translateY(24px) scale(.98); }
  to   { opacity: 1; transform: translateY(0)    scale(1);   }
}

/* ── 品牌區 ───────────────────────────────────────────────── */
.auth-brand {
  text-align: center;
  margin-bottom: 26px;
  width: 100%;
}
.auth-logo-icon {
  width: 62px; height: 62px;
  background: linear-gradient(140deg, #5294E8 0%, #3B7DD8 60%, #2d65b3 100%);
  border-radius: 20px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.8rem;
  margin: 0 auto 14px;
  box-shadow:
    0 4px 20px rgba(59,125,216,.32),
    0 1px 3px rgba(0,0,0,.08),
    inset 0 1px 0 rgba(255,255,255,.25);
  position: relative;
}
.auth-site-name {
  font-size: 1.65rem;
  font-weight: 800;
  color: var(--text-main);
  letter-spacing: -.02em;
  line-height: 1.2;
}
.auth-site-slogan {
  font-size: .875rem;
  color: var(--text-sub);
  margin-top: 4px;
}

/* ── 卡片 ─────────────────────────────────────────────────── */
.auth-card {
  width: 100%;
  background: rgba(255,255,255,.93);
  backdrop-filter: blur(24px) saturate(180%);
  -webkit-backdrop-filter: blur(24px) saturate(180%);
  border: 1px solid rgba(255,255,255,.85);
  border-radius: var(--radius-lg);
  padding: 36px 36px 28px;
  box-shadow:
    0 4px 28px rgba(59,125,216,.09),
    0 1px 4px rgba(0,0,0,.04),
    inset 0 1px 0 rgba(255,255,255,.95);
}

.auth-card-title {
  font-size: 1.28rem;
  font-weight: 700;
  color: var(--text-main);
  margin-bottom: 4px;
  line-height: 1.3;
}
.auth-card-sub {
  font-size: .875rem;
  color: var(--text-sub);
  margin-bottom: 24px;
  line-height: 1.5;
}

/* ── 功能亮點（註冊頁） ──────────────────────────────────── */
.auth-features {
  background: linear-gradient(135deg, rgba(59,125,216,.06) 0%, rgba(59,125,216,.02) 100%);
  border: 1px solid rgba(59,125,216,.12);
  border-radius: var(--radius-sm);
  padding: 14px 16px;
  margin-bottom: 22px;
}
.auth-features ul {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: 6px;
}
.auth-features li {
  font-size: .87rem;
  color: var(--text-sub);
  display: flex;
  align-items: flex-start;
  gap: 8px;
  line-height: 1.5;
}
.auth-features li .feat-icon {
  font-size: 1rem;
  flex-shrink: 0;
  margin-top: 1px;
}

/* ── 表單覆寫（認證頁更緊湊） ─────────────────────────────── */
.auth-card .form-label {
  font-size: .875rem;
  color: var(--gray-700);
}
.auth-card .form-control {
  height: 46px;
  font-size: .975rem;
  border-color: #dde3ef;
  background: rgba(255,255,255,.85);
  transition: border-color var(--dur), box-shadow var(--dur), background var(--dur);
}
.auth-card .form-control:hover {
  border-color: #c0ccdf;
  background: rgba(255,255,255,.95);
}
.auth-card .form-control:focus {
  background: #fff;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(59,125,216,.13);
}

/* ── 忘記密碼行 ───────────────────────────────────────────── */
.pwd-label-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 6px;
}
.pwd-label-row .form-label { margin-bottom: 0; }
.forgot-link {
  font-size: .82rem;
  color: var(--primary);
  text-decoration: none;
  font-weight: 500;
  transition: color var(--dur);
}
.forgot-link:hover { color: var(--primary-dark); text-decoration: underline; }

/* ── 送出按鈕 ─────────────────────────────────────────────── */
.auth-btn {
  height: 50px;
  font-size: 1.02rem;
  font-weight: 600;
  letter-spacing: .01em;
  border-radius: 8px;
  box-shadow: 0 3px 14px rgba(59,125,216,.30);
  margin-top: 8px;
}
.auth-btn:hover {
  box-shadow: 0 5px 20px rgba(59,125,216,.42);
  transform: translateY(-1px);
}
.auth-btn:active { transform: translateY(0); }

/* ── 密碼強度指示條 ──────────────────────────────────────── */
.pwd-strength-wrap { margin-top: 7px; display: none; }
.pwd-strength-wrap.visible { display: block; }
.pwd-strength-bars {
  display: flex;
  gap: 4px;
  margin-bottom: 5px;
}
.pwd-strength-bars .bar {
  flex: 1;
  height: 4px;
  border-radius: 99px;
  background: var(--gray-200);
  transition: background .3s;
}
/* 等級 1: 弱 */
.pwd-strength-wrap[data-level="1"] .bar:nth-child(1) { background: var(--danger); }
/* 等級 2: 普通 */
.pwd-strength-wrap[data-level="2"] .bar:nth-child(-n+2) { background: var(--warning); }
/* 等級 3: 良好 */
.pwd-strength-wrap[data-level="3"] .bar:nth-child(-n+3) { background: var(--primary); }
/* 等級 4: 強 */
.pwd-strength-wrap[data-level="4"] .bar { background: var(--success); }

.pwd-strength-text {
  font-size: .8rem;
  font-weight: 500;
}
.pwd-strength-wrap[data-level="1"] .pwd-strength-text { color: var(--danger);  }
.pwd-strength-wrap[data-level="2"] .pwd-strength-text { color: var(--warning); }
.pwd-strength-wrap[data-level="3"] .pwd-strength-text { color: var(--primary); }
.pwd-strength-wrap[data-level="4"] .pwd-strength-text { color: var(--success); }

/* ── 年級格子 ─────────────────────────────────────────────── */
.grade-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 8px;
}
.grade-pill {
  padding: 9px 6px;
  text-align: center;
  border: 1.5px solid #dde3ef;
  border-radius: var(--radius-sm);
  font-size: .85rem;
  font-weight: 500;
  color: var(--text-sub);
  cursor: pointer;
  background: rgba(255,255,255,.8);
  transition: all var(--dur) var(--ease);
  font-family: inherit;
  line-height: 1.3;
  user-select: none;
}
.grade-pill:hover {
  border-color: var(--primary);
  color: var(--primary);
  background: var(--primary-50);
  transform: translateY(-1px);
}
.grade-pill.selected {
  border-color: var(--primary);
  background: var(--primary);
  color: #fff;
  box-shadow: 0 2px 8px rgba(59,125,216,.28);
}
.grade-pill.grade-other { grid-column: span 2; }

/* 年級錯誤狀態 */
.grade-grid.is-invalid .grade-pill:not(.selected) {
  border-color: rgba(231,76,60,.35);
}

/* ── 帳號/Email 雙欄佈局 ─────────────────────────────────── */
.form-row-2 {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 14px;
  margin-bottom: 18px;
}

/* ── 底部連結 ─────────────────────────────────────────────── */
.auth-footer {
  text-align: center;
  margin-top: 20px;
  font-size: .875rem;
  color: var(--text-sub);
  width: 100%;
}
.auth-footer a {
  color: var(--primary);
  font-weight: 600;
  text-decoration: none;
}
.auth-footer a:hover { text-decoration: underline; }

.auth-version {
  text-align: center;
  margin-top: 14px;
  font-size: .75rem;
  color: var(--text-muted);
  width: 100%;
}

/* ── RWD ─────────────────────────────────────────────────── */
@media (max-width: 540px) {
  .auth-page { padding: 28px 14px 36px; }

  .auth-card { padding: 26px 20px 22px; }

  .form-row-2 { grid-template-columns: 1fr; gap: 0; }
  .form-row-2 > .form-group { margin-bottom: 18px; }

  .grade-grid { grid-template-columns: repeat(3, 1fr); }
  .grade-pill.grade-other { grid-column: span 1; }

  .auth-site-name { font-size: 1.4rem; }
}

@media (max-width: 380px) {
  .grade-grid { grid-template-columns: repeat(2, 1fr); }
  .grade-pill.grade-other { grid-column: span 2; }
}