/* ============================================================
   Study Decoder — Teacher Theme
   Premium "clean" upgrade for all teacher-facing surfaces.
   Linked AFTER each page's inline <style> so it wins the cascade
   and upgrades the existing shared class names (.card, .btn,
   .header, .form-input, .tab, …) without rewriting markup.
   No heavy animation — fast for a daily-use tool.
   ============================================================ */
:root {
  --primary: #f5a623;
  --primary-2: #ffb73d;
  --primary-glow: rgba(243,239,231,0.35);
  --accent: #f5a623;
  --bg: #14141a;
  --bg-card: #1c1c24;
  --bg-elevated: #25252f;
  --border: rgba(255,255,255,0.08);
  --text: #ffffff;
  --text-sec: rgba(255,255,255,0.82);
  --text-muted: rgba(255,255,255,0.55);
  --radius: 16px;
  --shadow-card: 0 8px 32px rgba(0,0,0,0.40);
  --shadow-glow: 0 8px 32px rgba(243,239,231,0.14);
  --transition: all .25s cubic-bezier(.2,.7,.2,1);
}

body {
  background:
    radial-gradient(ellipse 80% 50% at 50% -10%, rgba(243,239,231,0.10), transparent 60%),
    var(--bg) !important;
  color: var(--text);
}

/* ── Glassy sticky nav/header ── */
.header, .navbar {
  background: rgba(20,20,26,0.78) !important;
  backdrop-filter: blur(22px); -webkit-backdrop-filter: blur(22px);
  border-bottom: 1px solid var(--border) !important;
}
.header-title { letter-spacing: -0.3px; }
.back-btn { transition: var(--transition); }
.back-btn:hover { background: rgba(79,140,255,0.18); }

/* ── Cards with depth ── */
.card {
  background: linear-gradient(160deg, var(--bg-card), #1c1c24) !important;
  border: 1px solid var(--border) !important;
  border-radius: var(--radius) !important;
  box-shadow: var(--shadow-card);
}
.card.glow { box-shadow: var(--shadow-glow), var(--shadow-card); border-color: rgba(243,239,231,0.22) !important; }
.card.muted { background: rgba(255,255,255,0.02) !important; box-shadow: none; }

/* ── Buttons: gradient + glow + lift ── */
.btn {
  background: linear-gradient(135deg, #f5a623, #ffb73d) !important;
  border: none; border-radius: 12px;
  box-shadow: 0 4px 16px rgba(243,239,231,0.30);
  transition: var(--transition); font-weight: 700;
}
.btn:hover:not(:disabled) { transform: translateY(-2px); box-shadow: 0 10px 26px rgba(243,239,231,0.45); }
.btn:active:not(:disabled) { transform: translateY(0); }
.btn:disabled { opacity: .55; box-shadow: none; }
.btn-ghost {
  background: rgba(79,140,255,0.08) !important;
  border: 1px solid rgba(243,239,231,0.30) !important;
  color: var(--text) !important; box-shadow: none;
}
.btn-ghost:hover:not(:disabled) { background: rgba(243,239,231,0.16) !important; border-color: rgba(243,239,231,0.5) !important; transform: translateY(-1px); }
.btn-danger {
  background: rgba(220,53,69,0.14) !important; color: #ff8088 !important;
  border: 1px solid rgba(220,53,69,0.4) !important; box-shadow: none; border-radius: 10px;
}
.btn-danger:hover:not(:disabled) { background: rgba(220,53,69,0.22) !important; transform: translateY(-1px); }
.link-inline { color: var(--primary-2) !important; }

/* ── Inputs ── */
.form-input, .form-select, textarea, input[type="text"], input[type="email"], input[type="date"], input[type="number"] {
  background: #1c1c24 !important;
  border: 1px solid var(--border) !important;
  border-radius: 10px !important;
  transition: var(--transition);
}
.form-input:focus, .form-select:focus, textarea:focus, input:focus {
  outline: none; border-color: var(--primary) !important;
  box-shadow: 0 0 0 3px rgba(243,239,231,0.18);
}
.form-label { color: var(--text-sec); }

/* ── Tabs ── */
.tab { transition: var(--transition); border-radius: 10px 10px 0 0; }
.tab:hover { color: var(--text); }

/* ── Progress / mastery bars ── */
.bar, .progress-bar, .sc-value { }
.bar > div, .bar-fill { background: linear-gradient(90deg, #f5a623, #ffb73d) !important; }

/* ── Stat cards (Home command-centre) ── */
.sd-stat-grid {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 14px; margin-bottom: 22px;
}
.sd-stat {
  position: relative; overflow: hidden;
  background: linear-gradient(160deg, var(--bg-card), #1c1c24);
  border: 1px solid var(--border); border-radius: 14px;
  padding: 18px 20px; box-shadow: var(--shadow-card);
}
.sd-stat::before {
  content: ''; position: absolute; top: 0; left: 0; right: 0; height: 3px;
  background: linear-gradient(90deg, var(--accent-bar, #f5a623), transparent);
}
.sd-stat.s-students::before { --accent-bar: #f5a623; }
.sd-stat.s-review::before { --accent-bar: #fbbf24; }
.sd-stat.s-mastery::before { --accent-bar: #22c55e; }
.sd-stat.s-classes::before { --accent-bar: #38bdf8; }
.sd-stat .sd-stat-label { font-size: 12px; font-weight: 700; text-transform: uppercase; letter-spacing: .06em; color: var(--text-muted); margin-bottom: 8px; }
.sd-stat .sd-stat-value { font-size: 30px; font-weight: 900; color: #fff; line-height: 1; }
.sd-stat .sd-stat-sub { font-size: 12px; color: var(--text-muted); margin-top: 6px; }

/* ── Section heading for Home ── */
.sd-home-greet { font-size: 26px; font-weight: 800; letter-spacing: -0.4px; margin-bottom: 4px; }
.sd-home-greet .grad { background: linear-gradient(135deg,#ffb73d,#f5a623); -webkit-background-clip: text; background-clip: text; -webkit-text-fill-color: transparent; }
.sd-home-sub { color: var(--text-muted); font-size: 14px; margin-bottom: 22px; }
.sd-quick-actions { display: flex; gap: 10px; flex-wrap: wrap; margin-bottom: 22px; }

/* ── Activity / attention lists ── */
.sd-activity { list-style: none; padding: 0; margin: 0; }
.sd-activity li { display: flex; align-items: center; gap: 12px; padding: 11px 0; border-bottom: 1px solid var(--border); font-size: 14px; color: var(--text-sec); }
.sd-activity li:last-child { border-bottom: 0; }
.sd-activity .when { margin-left: auto; color: var(--text-muted); font-size: 12px; white-space: nowrap; }
.sd-chip { display: inline-block; font-size: 11px; font-weight: 700; padding: 2px 9px; border-radius: 999px; background: rgba(243,239,231,0.16); color: var(--primary-2); }

/* ── Delightful empty state ── */
.sd-empty { text-align: center; padding: 48px 24px; }
.sd-empty .ico { font-size: 44px; margin-bottom: 12px; }
.sd-empty h3 { font-size: 22px; font-weight: 800; margin-bottom: 8px; background: linear-gradient(135deg,#ffb73d,#f5a623); -webkit-background-clip: text; background-clip: text; -webkit-text-fill-color: transparent; }
.sd-empty p { color: var(--text-muted); font-size: 14px; line-height: 1.6; max-width: 420px; margin: 0 auto 18px; }

/* ── Glass modal helper (for new overlays) ── */
.sd-glass-overlay { background: rgba(0,0,0,0.78) !important; backdrop-filter: blur(8px); -webkit-backdrop-filter: blur(8px); }

/* ── Premium hero band (pricing + tool intros) ── */
.sd-hero-band {
  position: relative; overflow: hidden; text-align: center;
  padding: 3.4rem 5% 2.6rem;
  background: radial-gradient(ellipse 60% 100% at 50% 0%, rgba(243,239,231,0.18), transparent 65%);
}
.sd-hero-band h1 { font-size: clamp(1.8rem, 4vw, 2.7rem); font-weight: 800; line-height: 1.15; margin-bottom: .6rem; }
.sd-hero-band h1 .grad { background: linear-gradient(135deg,#ffb73d,#f5a623); -webkit-background-clip: text; background-clip: text; -webkit-text-fill-color: transparent; }
.sd-hero-band p { color: var(--text-sec); font-size: 1.02rem; max-width: 620px; margin: 0 auto; }

/* ── Branded loading ── */
.sd-loading { display: flex; flex-direction: column; align-items: center; gap: 14px; padding: 36px 16px; color: var(--text-muted); }
.sd-loading .ring { width: 42px; height: 42px; border: 3px solid rgba(243,239,231,0.2); border-top-color: var(--primary); border-radius: 50%; animation: sdSpin 0.9s linear infinite; }
@keyframes sdSpin { to { transform: rotate(360deg); } }

/* ── First-render fade-up (CSS-only, accessible) ── */
@keyframes sdFadeUp { from { opacity: 0; transform: translateY(10px); } to { opacity: 1; transform: none; } }
.sd-fade { animation: sdFadeUp .4s cubic-bezier(.2,.7,.2,1) both; }
@media (prefers-reduced-motion: reduce) {
  .sd-fade { animation: none; }
  .btn:hover, .btn-ghost:hover, .btn-danger:hover, .card:hover { transform: none !important; }
}