/* ═══════════════════════════════════════════════════════════
   LISa — Latihan Intensif Sains
   Design: Energetic Science Lab · Neon on Dark · Bold Type
   Fonts: Clash Display (headings) + Plus Jakarta Sans (body)
   ═══════════════════════════════════════════════════════════ */

@import url('https://fonts.googleapis.com/css2?family=Plus+Jakarta+Sans:wght@300;400;500;600;700;800&family=JetBrains+Mono:wght@400;500;600&display=swap');
@import url('https://api.fontshare.com/v2/css?f[]=clash-display@400,500,600,700&display=swap');

:root {
  /* Core palette — deep space science lab */
  --bg:       #05070F;
  --bg2:      #0C0F1D;
  --bg3:      #111528;
  --bg4:      #171C34;
  --bg5:      #1D2340;

  /* Borders */
  --border:   rgba(255,255,255,0.06);
  --border2:  rgba(255,255,255,0.12);
  --border3:  rgba(255,255,255,0.18);

  /* Text */
  --text:     #F0F2FF;
  --text2:    #8892B0;
  --text3:    #4A5280;

  /* Brand — electric cyan + magenta science energy */
  --cyan:       #00F5FF;
  --cyan-dim:   rgba(0,245,255,0.12);
  --cyan-glow:  rgba(0,245,255,0.25);
  --magenta:    #FF2D9B;
  --magenta-dim:rgba(255,45,155,0.12);
  --violet:     #7C3AED;
  --violet-dim: rgba(124,58,237,0.15);

  /* Accent (primary interactive) */
  --accent:     #00F5FF;
  --accent2:    #33F7FF;
  --accent-bg:  rgba(0,245,255,0.08);
  --accent-glow:rgba(0,245,255,0.2);

  /* Semantic */
  --green:      #00E676;
  --green-dim:  rgba(0,230,118,0.12);
  --amber:      #FFB300;
  --amber-dim:  rgba(255,179,0,0.12);
  --red:        #FF3D71;
  --red-dim:    rgba(255,61,113,0.12);
  --blue:       #2979FF;
  --blue-dim:   rgba(41,121,255,0.12);

  /* Difficulty */
  --easy:   #00E676;
  --medium: #FFB300;
  --hard:   #FF3D71;

  /* Layout */
  --sidebar-w: 248px;
  --radius:    10px;
  --radius-lg: 16px;
  --radius-xl: 22px;

  /* Shadows */
  --shadow:    0 4px 32px rgba(0,0,0,0.5);
  --shadow-lg: 0 8px 64px rgba(0,0,0,0.6);
  --glow-cyan: 0 0 30px rgba(0,245,255,0.2);
  --glow-mg:   0 0 30px rgba(255,45,155,0.2);

  /* Typography */
  --font-head: 'Clash Display', 'Plus Jakarta Sans', sans-serif;
  --font-body: 'Plus Jakarta Sans', sans-serif;
  --font-mono: 'JetBrains Mono', monospace;

  /* Motion */
  --ease:      cubic-bezier(0.4, 0, 0.2, 1);
  --ease-out:  cubic-bezier(0, 0, 0.2, 1);
  --ease-spring: cubic-bezier(0.34, 1.56, 0.64, 1);
  --t:  0.18s;
  --ts: 0.35s;
}

/* ── Reset ───────────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { font-size: 16px; scroll-behavior: smooth; -webkit-font-smoothing: antialiased; }
body {
  font-family: var(--font-body);
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  overflow-x: hidden;
  line-height: 1.6;
}
a { color: inherit; text-decoration: none; }
button { cursor: pointer; border: none; font-family: var(--font-body); }
input, textarea, select {
  font-family: var(--font-body);
  color: var(--text);
  background: var(--bg3);
  border: 1px solid var(--border2);
  border-radius: var(--radius);
  padding: 10px 14px;
  font-size: 0.92rem;
  outline: none;
  transition: border-color var(--t) var(--ease), box-shadow var(--t) var(--ease);
  width: 100%;
}
input:focus, textarea:focus, select:focus {
  border-color: var(--cyan);
  box-shadow: 0 0 0 3px var(--cyan-dim), 0 0 12px var(--cyan-glow);
}
input::placeholder { color: var(--text3); }
select option { background: var(--bg3); }

/* ── Background grid texture ─────────────────────────────── */
body::before {
  content: '';
  position: fixed; inset: 0; z-index: 0; pointer-events: none;
  background-image:
    linear-gradient(rgba(0,245,255,0.03) 1px, transparent 1px),
    linear-gradient(90deg, rgba(0,245,255,0.03) 1px, transparent 1px);
  background-size: 48px 48px;
}
#app { position: relative; z-index: 1; }

/* ── Splash ──────────────────────────────────────────────── */
.splash {
  position: fixed; inset: 0; z-index: 9999;
  background: var(--bg);
  display: flex; flex-direction: column;
  align-items: center; justify-content: center; gap: 16px;
}
.splash::after {
  content: '';
  position: absolute; inset: 0;
  background: radial-gradient(ellipse 60% 50% at 50% 50%, rgba(0,245,255,0.06) 0%, transparent 70%);
}
.splash-logo {
  display: flex; align-items: center; gap: 14px;
  font-family: var(--font-head); font-size: 3.5rem; font-weight: 700;
  letter-spacing: -0.03em; position: relative; z-index: 1;
}
.splash-icon { font-size: 3rem; animation: floatIcon 2s ease-in-out infinite; }
@keyframes floatIcon { 0%,100%{transform:translateY(0) rotate(0deg)} 50%{transform:translateY(-6px) rotate(10deg)} }
.splash-name {
  background: linear-gradient(135deg, var(--cyan), var(--magenta));
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
  filter: drop-shadow(0 0 20px var(--cyan-glow));
}
.splash-sub {
  color: var(--text3); font-size: 0.78rem; letter-spacing: 0.2em;
  text-transform: uppercase; position: relative; z-index: 1;
}
.splash-loader {
  width: 180px; height: 2px; background: var(--bg4);
  border-radius: 99px; overflow: hidden; margin-top: 24px; position: relative; z-index: 1;
}
.splash-bar {
  height: 100%;
  background: linear-gradient(90deg, var(--cyan), var(--magenta), var(--cyan));
  background-size: 200%;
  border-radius: 99px;
  animation: splashLoad 1.6s ease-in-out infinite;
}
@keyframes splashLoad {
  0%   { width: 0; margin-left: 0; background-position: 0% }
  50%  { width: 60%; margin-left: 20%; background-position: 100% }
  100% { width: 0; margin-left: 100%; background-position: 200% }
}

/* ── Layout ──────────────────────────────────────────────── */
.layout { display: flex; min-height: 100vh; }

/* ── Sidebar ─────────────────────────────────────────────── */
.sidebar {
  width: var(--sidebar-w);
  min-height: 100vh;
  background: var(--bg2);
  border-right: 1px solid var(--border);
  display: flex; flex-direction: column;
  position: fixed; left: 0; top: 0; bottom: 0; z-index: 100;
  transition: transform var(--ts) var(--ease);
}

/* Sidebar glow strip */
.sidebar::after {
  content: '';
  position: absolute; top: 0; right: -1px; width: 1px; height: 100%;
  background: linear-gradient(180deg, transparent 0%, var(--cyan) 40%, var(--magenta) 70%, transparent 100%);
  opacity: 0.3;
}

.sidebar-logo {
  padding: 22px 20px 18px;
  display: flex; align-items: center; gap: 10px;
  border-bottom: 1px solid var(--border);
  position: relative;
}
.sidebar-logo-icon {
  width: 36px; height: 36px; border-radius: 10px;
  background: linear-gradient(135deg, var(--cyan-dim), var(--magenta-dim));
  border: 1px solid rgba(0,245,255,0.2);
  display: flex; align-items: center; justify-content: center;
  font-size: 1.1rem;
}
.sidebar-logo-text {
  font-family: var(--font-head); font-size: 1.4rem; font-weight: 700;
  letter-spacing: -0.02em; line-height: 1;
}
.sidebar-logo-text span {
  background: linear-gradient(135deg, var(--cyan), var(--magenta));
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
}
.sidebar-logo-sub {
  display: block; font-size: 0.58rem; color: var(--text3);
  text-transform: uppercase; letter-spacing: 0.12em; margin-top: 2px;
}

.sidebar-user {
  margin: 14px 12px;
  padding: 12px 14px;
  background: var(--bg3);
  border: 1px solid var(--border2);
  border-radius: var(--radius-lg);
  display: flex; align-items: center; gap: 10px;
  position: relative; overflow: hidden;
}
.sidebar-user::before {
  content: '';
  position: absolute; top: 0; left: 0; right: 0; height: 1px;
  background: linear-gradient(90deg, transparent, var(--cyan), transparent);
  opacity: 0.4;
}
.avatar {
  width: 34px; height: 34px; border-radius: 10px;
  display: flex; align-items: center; justify-content: center;
  font-weight: 700; font-size: 0.82rem; flex-shrink: 0;
  font-family: var(--font-head);
  border: 1px solid rgba(255,255,255,0.1);
}
.sidebar-user-info { flex: 1; min-width: 0; }
.sidebar-user-name {
  font-size: 0.84rem; font-weight: 700;
  white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
  letter-spacing: -0.01em;
}
.sidebar-user-level { font-size: 0.68rem; color: var(--text3); margin-top: 1px; }

.sidebar-nav { flex: 1; padding: 6px 0; overflow-y: auto; }
.nav-section { padding: 4px 0; }
.nav-label {
  font-size: 0.6rem; text-transform: uppercase; letter-spacing: 0.16em;
  color: var(--text3); padding: 10px 20px 4px;
  font-weight: 600;
}
.nav-item {
  display: flex; align-items: center; gap: 10px;
  padding: 9px 18px; margin: 1px 8px;
  font-size: 0.86rem; font-weight: 500; color: var(--text2);
  cursor: pointer; transition: all var(--t) var(--ease);
  border-radius: var(--radius);
  position: relative;
}
.nav-item:hover { color: var(--text); background: var(--bg3); }
.nav-item.active {
  color: var(--cyan);
  background: var(--cyan-dim);
  border: 1px solid rgba(0,245,255,0.15);
}
.nav-item.active::before {
  content: '';
  position: absolute; left: -8px; top: 50%; transform: translateY(-50%);
  width: 3px; height: 18px; border-radius: 0 3px 3px 0;
  background: var(--cyan);
  box-shadow: 0 0 8px var(--cyan);
}
.nav-icon { font-size: 0.95rem; width: 18px; text-align: center; }

.sidebar-xp {
  padding: 12px 16px 14px;
  border-top: 1px solid var(--border);
}
.xp-bar-wrap {
  display: flex; align-items: center; justify-content: space-between;
  margin-bottom: 6px;
}
.xp-label { font-size: 0.7rem; color: var(--text2); font-weight: 600; }
.xp-number { font-size: 0.7rem; color: var(--cyan); font-family: var(--font-mono); font-weight: 500; }
.xp-bar {
  height: 5px; background: var(--bg4); border-radius: 99px;
  overflow: hidden; position: relative;
}
.xp-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--cyan), var(--magenta));
  border-radius: 99px;
  transition: width 0.8s var(--ease-out);
  box-shadow: 0 0 8px var(--cyan-glow);
}
.streak-badge {
  display: flex; align-items: center; gap: 4px;
  font-size: 0.68rem; color: var(--amber); margin-top: 6px;
  font-weight: 600;
}

/* ── Main Content ─────────────────────────────────────────── */
.main { margin-left: var(--sidebar-w); flex: 1; min-height: 100vh; }
.page {
  padding: 32px 36px;
  max-width: 1160px;
  animation: pageIn 0.3s var(--ease-out);
}
@keyframes pageIn {
  from { opacity: 0; transform: translateY(10px); }
  to   { opacity: 1; transform: translateY(0); }
}

/* ── Page Header ─────────────────────────────────────────── */
.page-header { margin-bottom: 28px; }
.page-title {
  font-family: var(--font-head); font-size: 1.9rem; font-weight: 700;
  letter-spacing: -0.03em; line-height: 1.1;
}
.page-sub { color: var(--text2); font-size: 0.9rem; margin-top: 5px; }

/* ── Cards ───────────────────────────────────────────────── */
.card {
  background: var(--bg2);
  border: 1px solid var(--border2);
  border-radius: var(--radius-lg);
  padding: 20px;
  transition: border-color var(--t) var(--ease), box-shadow var(--t) var(--ease);
  position: relative; overflow: hidden;
}
.card::before {
  content: '';
  position: absolute; top: 0; left: 0; right: 0; height: 1px;
  background: linear-gradient(90deg, transparent, rgba(0,245,255,0.15), transparent);
}
.card.clickable { cursor: pointer; }
.card.clickable:hover {
  border-color: rgba(0,245,255,0.2);
  box-shadow: var(--glow-cyan), var(--shadow);
  transform: translateY(-2px);
}

/* ── Stat Cards ──────────────────────────────────────────── */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(175px, 1fr));
  gap: 14px; margin-bottom: 24px;
}
.stat-card {
  background: var(--bg2); border: 1px solid var(--border2);
  border-radius: var(--radius-lg); padding: 18px 20px;
  display: flex; flex-direction: column; gap: 8px;
  position: relative; overflow: hidden;
  transition: all var(--t) var(--ease);
}
.stat-card:hover { border-color: var(--border3); transform: translateY(-2px); }
.stat-card::after {
  content: '';
  position: absolute; bottom: 0; left: 0; right: 0; height: 2px;
  background: linear-gradient(90deg, var(--cyan), var(--magenta));
  opacity: 0; transition: opacity var(--t) var(--ease);
}
.stat-card:hover::after { opacity: 1; }
.stat-icon { font-size: 1.4rem; }
.stat-value {
  font-family: var(--font-head); font-size: 2rem; font-weight: 700;
  letter-spacing: -0.03em; line-height: 1;
}
.stat-label {
  font-size: 0.72rem; color: var(--text2);
  text-transform: uppercase; letter-spacing: 0.1em; font-weight: 600;
}
.stat-change { font-size: 0.75rem; color: var(--green); font-weight: 500; }

/* ── Buttons ─────────────────────────────────────────────── */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 7px;
  padding: 10px 20px; border-radius: var(--radius);
  font-size: 0.88rem; font-weight: 700; letter-spacing: 0.01em;
  transition: all var(--t) var(--ease);
  position: relative; overflow: hidden;
}
.btn-primary {
  background: linear-gradient(135deg, var(--cyan), #00B8C2);
  color: #000;
  box-shadow: 0 4px 20px var(--cyan-dim);
}
.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 28px var(--cyan-glow);
  filter: brightness(1.1);
}
.btn-secondary {
  background: var(--bg3);
  color: var(--text2);
  border: 1px solid var(--border2);
}
.btn-secondary:hover {
  background: var(--bg4);
  color: var(--text);
  border-color: var(--border3);
}
.btn-magenta {
  background: linear-gradient(135deg, var(--magenta), #C71585);
  color: white;
  box-shadow: 0 4px 20px var(--magenta-dim);
}
.btn-magenta:hover { transform: translateY(-2px); box-shadow: var(--glow-mg); }
.btn-danger {
  background: var(--red-dim); color: var(--red);
  border: 1px solid rgba(255,61,113,0.2);
}
.btn-danger:hover { background: rgba(255,61,113,0.2); }
.btn-success {
  background: var(--green-dim); color: var(--green);
  border: 1px solid rgba(0,230,118,0.2);
}
.btn-sm { padding: 6px 12px; font-size: 0.78rem; }
.btn:disabled { opacity: 0.4; cursor: not-allowed; transform: none !important; filter: none !important; }
.btn-icon { width: 34px; height: 34px; padding: 0; border-radius: var(--radius); }

/* ── Badges ──────────────────────────────────────────────── */
.badge {
  display: inline-flex; align-items: center; gap: 4px;
  padding: 3px 10px; border-radius: 99px;
  font-size: 0.7rem; font-weight: 700; letter-spacing: 0.04em;
  text-transform: uppercase;
}
.badge-easy   { background: var(--green-dim); color: var(--easy); border: 1px solid rgba(0,230,118,0.2); }
.badge-medium { background: var(--amber-dim); color: var(--medium); border: 1px solid rgba(255,179,0,0.2); }
.badge-hard   { background: var(--red-dim); color: var(--hard); border: 1px solid rgba(255,61,113,0.2); }
.badge-accent { background: var(--cyan-dim); color: var(--cyan); border: 1px solid rgba(0,245,255,0.2); }
.badge-teal   { background: var(--green-dim); color: var(--green); border: 1px solid rgba(0,230,118,0.2); }
.badge-violet { background: var(--violet-dim); color: #A78BFA; border: 1px solid rgba(124,58,237,0.2); }

/* ── Task Cards ──────────────────────────────────────────── */
.tasks-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(290px, 1fr));
  gap: 14px;
}
.task-card {
  background: var(--bg2); border: 1px solid var(--border2);
  border-radius: var(--radius-lg); padding: 18px 20px;
  cursor: pointer; transition: all var(--t) var(--ease);
  display: flex; flex-direction: column; gap: 12px;
  position: relative; overflow: hidden;
}
.task-card::before {
  content: ''; position: absolute; top: 0; left: 0; right: 0; height: 2px;
  background: var(--card-accent, linear-gradient(90deg, var(--cyan), var(--magenta)));
}
.task-card::after {
  content: '';
  position: absolute; inset: 0;
  background: radial-gradient(ellipse 80% 60% at 50% 0%, rgba(0,245,255,0.04), transparent);
  pointer-events: none;
}
.task-card:hover {
  border-color: rgba(0,245,255,0.25);
  box-shadow: var(--glow-cyan), var(--shadow);
  transform: translateY(-3px);
}
.task-card-header { display: flex; align-items: flex-start; justify-content: space-between; gap: 8px; }
.task-card-subject {
  font-size: 0.7rem; color: var(--text3); display: flex;
  align-items: center; gap: 4px; text-transform: uppercase; letter-spacing: 0.08em;
}
.task-card-title { font-size: 0.95rem; font-weight: 700; line-height: 1.4; margin-top: 4px; letter-spacing: -0.01em; }
.task-card-desc { font-size: 0.82rem; color: var(--text2); line-height: 1.55; }
.task-card-footer { display: flex; align-items: center; gap: 7px; flex-wrap: wrap; }

/* ── Forms ───────────────────────────────────────────────── */
.form-group { display: flex; flex-direction: column; gap: 6px; }
.form-label { font-size: 0.78rem; font-weight: 700; color: var(--text2); text-transform: uppercase; letter-spacing: 0.06em; }
.form-row { display: grid; gap: 14px; }
.form-row-2 { grid-template-columns: 1fr 1fr; }
.form-row-3 { grid-template-columns: 1fr 1fr 1fr; }
.form-hint { font-size: 0.75rem; color: var(--text3); }
.form-error { font-size: 0.8rem; color: var(--red); }

/* ── LOGIN PAGE ──────────────────────────────────────────── */
.login-page {
  min-height: 100vh; display: flex;
  background: var(--bg);
  position: relative; overflow: hidden;
}

/* Animated background orbs */
.login-bg {
  position: absolute; inset: 0; z-index: 0; pointer-events: none;
}
.login-bg::before {
  content: '';
  position: absolute; width: 600px; height: 600px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(0,245,255,0.08) 0%, transparent 70%);
  top: -100px; left: -100px;
  animation: orb1 8s ease-in-out infinite;
}
.login-bg::after {
  content: '';
  position: absolute; width: 500px; height: 500px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(255,45,155,0.08) 0%, transparent 70%);
  bottom: -100px; right: 300px;
  animation: orb2 10s ease-in-out infinite;
}
@keyframes orb1 { 0%,100%{transform:translate(0,0)} 50%{transform:translate(60px,40px)} }
@keyframes orb2 { 0%,100%{transform:translate(0,0)} 50%{transform:translate(-40px,-60px)} }

.login-grid-pattern {
  position: absolute; inset: 0; z-index: 0;
  background-image:
    linear-gradient(rgba(0,245,255,0.025) 1px, transparent 1px),
    linear-gradient(90deg, rgba(0,245,255,0.025) 1px, transparent 1px);
  background-size: 40px 40px;
}

.login-left {
  flex: 1; display: flex; flex-direction: column;
  align-items: center; justify-content: center;
  padding: 60px 48px; position: relative; z-index: 1;
}
.login-brand { text-align: center; margin-bottom: 56px; }
.login-brand-icon {
  font-size: 4.5rem; display: block; margin-bottom: 16px;
  animation: floatIcon 3s ease-in-out infinite;
}
.login-brand-name {
  font-family: var(--font-head); font-size: 5rem; font-weight: 700;
  letter-spacing: -0.04em; line-height: 0.9;
  background: linear-gradient(135deg, var(--cyan) 0%, #00B8FF 40%, var(--magenta) 100%);
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
  filter: drop-shadow(0 0 30px rgba(0,245,255,0.4));
}
.login-brand-tagline {
  color: var(--text3); font-size: 0.82rem; margin-top: 10px;
  letter-spacing: 0.18em; text-transform: uppercase;
}

.login-features { display: flex; flex-direction: column; gap: 10px; max-width: 360px; width: 100%; }
.login-feature {
  display: flex; align-items: center; gap: 14px;
  padding: 14px 18px;
  background: rgba(255,255,255,0.03);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  transition: all var(--t) var(--ease);
}
.login-feature:hover {
  background: rgba(0,245,255,0.04);
  border-color: rgba(0,245,255,0.15);
  transform: translateX(4px);
}
.login-feature-icon { font-size: 1.3rem; flex-shrink: 0; }
.login-feature-text strong {
  display: block; color: var(--text); font-size: 0.88rem;
  font-weight: 700; margin-bottom: 1px;
}
.login-feature-text { font-size: 0.8rem; color: var(--text2); }

.login-right {
  width: 460px; display: flex; align-items: center; justify-content: center;
  padding: 48px 44px;
  background: var(--bg2);
  border-left: 1px solid var(--border);
  position: relative; z-index: 1;
}
.login-right::before {
  content: '';
  position: absolute; top: 0; left: 0; bottom: 0; width: 1px;
  background: linear-gradient(180deg, transparent, var(--cyan), var(--magenta), transparent);
  opacity: 0.3;
}
.login-form-wrap { width: 100%; }
.login-form-title {
  font-family: var(--font-head); font-size: 2rem; font-weight: 700;
  letter-spacing: -0.03em; margin-bottom: 4px;
}
.login-form-sub { color: var(--text2); font-size: 0.88rem; margin-bottom: 28px; }

.login-tabs {
  display: flex; gap: 3px; margin-bottom: 28px;
  background: var(--bg3); padding: 4px; border-radius: var(--radius-lg);
  border: 1px solid var(--border);
}
.login-tab {
  flex: 1; padding: 9px; border-radius: 10px;
  text-align: center; font-size: 0.84rem; font-weight: 700;
  color: var(--text3); cursor: pointer;
  transition: all var(--t) var(--ease);
  letter-spacing: 0.02em;
}
.login-tab.active {
  background: linear-gradient(135deg, var(--cyan), #00B8FF);
  color: #000;
  box-shadow: 0 2px 12px var(--cyan-glow);
}

.login-form { display: flex; flex-direction: column; gap: 14px; }
.login-divider {
  display: flex; align-items: center; gap: 12px; margin: 2px 0;
}
.login-divider-line { flex: 1; height: 1px; background: var(--border); }
.login-divider-text { font-size: 0.75rem; color: var(--text3); }

.login-btn {
  width: 100%; padding: 13px;
  background: linear-gradient(135deg, var(--cyan), #00B8FF);
  color: #000; border-radius: var(--radius);
  font-size: 0.92rem; font-weight: 800; letter-spacing: 0.04em;
  border: none; cursor: pointer;
  transition: all var(--t) var(--ease);
  box-shadow: 0 4px 20px var(--cyan-dim);
}
.login-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 30px var(--cyan-glow);
  filter: brightness(1.08);
}
.login-btn:disabled { opacity: 0.5; cursor: not-allowed; transform: none; filter: none; }
.login-error {
  background: var(--red-dim); border: 1px solid rgba(255,61,113,0.25);
  color: var(--red); padding: 10px 14px; border-radius: var(--radius);
  font-size: 0.84rem;
}

/* ── Subject Cards ───────────────────────────────────────── */
.subject-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(170px, 1fr));
  gap: 12px; margin-bottom: 24px;
}
.subject-card {
  background: var(--bg2); border: 1px solid var(--border2);
  border-radius: var(--radius-lg); padding: 18px 16px;
  cursor: pointer; transition: all var(--t) var(--ease);
  text-align: center; position: relative; overflow: hidden;
}
.subject-card::after {
  content: '';
  position: absolute; inset: 0;
  background: radial-gradient(ellipse 80% 60% at 50% 0%, rgba(0,245,255,0.05), transparent);
  pointer-events: none; opacity: 0;
  transition: opacity var(--t) var(--ease);
}
.subject-card:hover { transform: translateY(-3px); }
.subject-card:hover::after { opacity: 1; }
.subject-card.selected {
  border-width: 1.5px;
  box-shadow: 0 0 20px var(--accent-glow);
}
.subject-icon { font-size: 2rem; margin-bottom: 8px; display: block; }
.subject-name { font-weight: 700; font-size: 0.92rem; font-family: var(--font-head); letter-spacing: -0.01em; }
.subject-count { font-size: 0.72rem; color: var(--text3); margin-top: 4px; }

/* ── AI Chat ─────────────────────────────────────────────── */
.ai-chat {
  display: flex; flex-direction: column;
  height: calc(100vh - 140px);
  background: var(--bg2); border: 1px solid var(--border2);
  border-radius: var(--radius-xl); overflow: hidden;
  box-shadow: var(--shadow);
}
.ai-chat-header {
  padding: 14px 18px; border-bottom: 1px solid var(--border);
  display: flex; align-items: center; gap: 10px;
  background: var(--bg3);
  position: relative;
}
.ai-chat-header::after {
  content: '';
  position: absolute; bottom: -1px; left: 0; right: 0; height: 1px;
  background: linear-gradient(90deg, transparent, var(--cyan), transparent);
  opacity: 0.3;
}
.ai-chat-avatar {
  width: 34px; height: 34px; border-radius: 10px;
  background: linear-gradient(135deg, var(--cyan-dim), var(--magenta-dim));
  border: 1px solid rgba(0,245,255,0.25);
  display: flex; align-items: center; justify-content: center;
  font-size: 0.95rem;
  box-shadow: 0 0 12px var(--cyan-dim);
}
.ai-chat-title { font-weight: 700; font-size: 0.9rem; letter-spacing: -0.01em; }
.ai-chat-status {
  font-size: 0.7rem; color: var(--green);
  display: flex; align-items: center; gap: 5px;
}
.ai-chat-status::before {
  content: ''; width: 5px; height: 5px;
  background: var(--green); border-radius: 50%;
  display: inline-block;
  animation: pulse 2s infinite;
  box-shadow: 0 0 6px var(--green);
}
@keyframes pulse { 0%,100%{opacity:1} 50%{opacity:0.3} }

.ai-messages {
  flex: 1; overflow-y: auto; padding: 20px;
  display: flex; flex-direction: column; gap: 14px;
}
.msg { max-width: 80%; display: flex; flex-direction: column; gap: 3px; }
.msg-user { align-self: flex-end; align-items: flex-end; }
.msg-ai   { align-self: flex-start; align-items: flex-start; }
.msg-bubble {
  padding: 10px 14px; border-radius: 14px;
  font-size: 0.88rem; line-height: 1.65;
}
.msg-user .msg-bubble {
  background: linear-gradient(135deg, var(--cyan), #00B8FF);
  color: #000; font-weight: 500;
  border-bottom-right-radius: 4px;
  box-shadow: 0 4px 16px var(--cyan-dim);
}
.msg-ai .msg-bubble {
  background: var(--bg3); border: 1px solid var(--border2);
  border-bottom-left-radius: 4px;
}
.msg-ai .msg-bubble h1,.msg-ai .msg-bubble h2,.msg-ai .msg-bubble h3 {
  font-size: 1em; font-weight: 700; margin: 10px 0 5px; color: var(--cyan);
}
.msg-ai .msg-bubble p { margin-bottom: 8px; }
.msg-ai .msg-bubble p:last-child { margin-bottom: 0; }
.msg-ai .msg-bubble ul,.msg-ai .msg-bubble ol { padding-left: 18px; margin-bottom: 8px; }
.msg-ai .msg-bubble code {
  background: var(--bg4); padding: 1px 6px; border-radius: 4px;
  font-family: var(--font-mono); font-size: 0.85em; color: var(--cyan);
}
.msg-ai .msg-bubble pre {
  background: var(--bg4); border-radius: 8px; padding: 10px;
  overflow-x: auto; margin: 8px 0; border: 1px solid var(--border);
}
.msg-ai .msg-bubble strong { color: var(--cyan); }
.msg-time { font-size: 0.66rem; color: var(--text3); }

.msg-typing { display: flex; gap: 4px; padding: 12px 14px; align-items: center; }
.msg-typing span {
  width: 6px; height: 6px; background: var(--text3); border-radius: 50%;
  animation: typingBounce 1.2s infinite;
}
.msg-typing span:nth-child(2) { animation-delay: 0.15s; }
.msg-typing span:nth-child(3) { animation-delay: 0.3s; }
@keyframes typingBounce { 0%,100%{transform:translateY(0);opacity:0.4} 40%{transform:translateY(-6px);opacity:1} }

.ai-chat-input {
  padding: 14px 16px; border-top: 1px solid var(--border);
  display: flex; gap: 10px; align-items: flex-end;
  background: var(--bg3);
}
.ai-chat-input textarea {
  flex: 1; resize: none; min-height: 40px; max-height: 120px;
  border-radius: 10px; line-height: 1.5; font-size: 0.88rem;
  background: var(--bg4); border-color: var(--border2);
}
.ai-send-btn {
  width: 40px; height: 40px; border-radius: 10px; flex-shrink: 0;
  background: linear-gradient(135deg, var(--cyan), #00B8FF);
  color: #000; font-size: 1rem; font-weight: 800;
  transition: all var(--t) var(--ease);
  display: flex; align-items: center; justify-content: center;
  box-shadow: 0 4px 12px var(--cyan-dim);
}
.ai-send-btn:hover { transform: scale(1.08); box-shadow: 0 4px 20px var(--cyan-glow); }
.ai-send-btn:disabled { opacity: 0.4; cursor: not-allowed; transform: none; }

/* ── Timer ───────────────────────────────────────────────── */
.timer-display {
  font-family: var(--font-mono); font-size: 2rem; font-weight: 600;
  text-align: center; padding: 6px 18px;
  border-radius: var(--radius);
  background: var(--bg3); border: 1px solid var(--border2);
  color: var(--cyan); letter-spacing: 0.08em;
  box-shadow: 0 0 20px var(--cyan-dim);
  transition: color var(--t) var(--ease);
}
.timer-warning { color: var(--amber) !important; box-shadow: 0 0 20px var(--amber-dim) !important; }
.timer-danger  {
  color: var(--red) !important; box-shadow: 0 0 20px var(--red-dim) !important;
  animation: timerPulse 0.5s infinite;
}
@keyframes timerPulse { 0%,100%{opacity:1} 50%{opacity:0.5} }

/* ── Difficulty Selector ─────────────────────────────────── */
.diff-selector { display: flex; gap: 12px; justify-content: center; }
.diff-option {
  flex: 1; max-width: 170px; padding: 18px 16px;
  border: 1.5px solid var(--border2); border-radius: var(--radius-lg);
  cursor: pointer; transition: all var(--t) var(--ease);
  text-align: center; background: var(--bg2);
  position: relative; overflow: hidden;
}
.diff-option::before {
  content: ''; position: absolute; inset: 0;
  background: radial-gradient(ellipse 80% 60% at 50% 0%, rgba(255,255,255,0.03), transparent);
}
.diff-option:hover { border-color: var(--border3); transform: translateY(-2px); }
.diff-option.selected-easy   { border-color: var(--easy);   background: var(--green-dim); box-shadow: 0 0 20px rgba(0,230,118,0.15); }
.diff-option.selected-medium { border-color: var(--medium); background: var(--amber-dim); box-shadow: 0 0 20px rgba(255,179,0,0.15); }
.diff-option.selected-hard   { border-color: var(--hard);   background: var(--red-dim);   box-shadow: 0 0 20px rgba(255,61,113,0.15); }
.diff-icon { font-size: 1.6rem; margin-bottom: 8px; }
.diff-name { font-weight: 800; font-size: 0.92rem; font-family: var(--font-head); letter-spacing: 0.02em; }
.diff-time { font-size: 0.75rem; color: var(--text2); font-family: var(--font-mono); margin-top: 4px; }
.diff-xp   { font-size: 0.78rem; font-weight: 700; margin-top: 4px; }

/* ── Quiz ────────────────────────────────────────────────── */
.quiz-wrap { max-width: 700px; margin: 0 auto; }
.quiz-progress { display: flex; gap: 5px; margin-bottom: 24px; }
.quiz-progress-dot {
  flex: 1; height: 3px; border-radius: 99px;
  background: var(--bg4); transition: background 0.4s var(--ease);
}
.quiz-progress-dot.done    { background: var(--green); box-shadow: 0 0 6px rgba(0,230,118,0.4); }
.quiz-progress-dot.current { background: var(--cyan);  box-shadow: 0 0 6px var(--cyan-glow); }

.quiz-question {
  background: var(--bg2); border: 1px solid var(--border2);
  border-radius: var(--radius-lg); padding: 22px 24px; margin-bottom: 14px;
  position: relative; overflow: hidden;
}
.quiz-question::before {
  content: ''; position: absolute; top: 0; left: 0; right: 0; height: 2px;
  background: linear-gradient(90deg, var(--cyan), var(--magenta));
}
.quiz-q-num {
  font-size: 0.68rem; color: var(--text3); text-transform: uppercase;
  letter-spacing: 0.12em; margin-bottom: 8px; font-weight: 600;
}
.quiz-q-text { font-size: 1rem; font-weight: 600; line-height: 1.6; letter-spacing: -0.01em; }

.quiz-options { display: flex; flex-direction: column; gap: 9px; }
.quiz-option {
  display: flex; align-items: center; gap: 12px;
  padding: 12px 16px; border-radius: var(--radius);
  border: 1.5px solid var(--border2); cursor: pointer;
  transition: all var(--t) var(--ease); font-size: 0.88rem;
  background: var(--bg2);
}
.quiz-option:hover { border-color: rgba(0,245,255,0.3); background: var(--cyan-dim); }
.quiz-option.selected { border-color: var(--cyan); background: var(--cyan-dim); }
.quiz-option.correct  { border-color: var(--green); background: var(--green-dim); }
.quiz-option.wrong    { border-color: var(--red);   background: var(--red-dim); }
.quiz-option-key {
  width: 28px; height: 28px; border-radius: 7px; flex-shrink: 0;
  background: var(--bg3); border: 1px solid var(--border2);
  display: flex; align-items: center; justify-content: center;
  font-size: 0.78rem; font-weight: 700; font-family: var(--font-mono);
  transition: all var(--t) var(--ease);
}
.quiz-option.selected .quiz-option-key { background: var(--cyan); border-color: var(--cyan); color: #000; }
.quiz-option.correct  .quiz-option-key { background: var(--green); border-color: var(--green); color: #000; }
.quiz-option.wrong    .quiz-option-key { background: var(--red); border-color: var(--red); color: #fff; }

/* ── Results ─────────────────────────────────────────────── */
.result-screen { text-align: center; padding: 40px 20px; max-width: 520px; margin: 0 auto; }
.result-score-ring {
  width: 130px; height: 130px; border-radius: 50%;
  background: conic-gradient(var(--cyan) calc(var(--score) * 1%), var(--bg3) 0);
  display: flex; align-items: center; justify-content: center;
  margin: 0 auto 20px;
  box-shadow: 0 0 40px var(--cyan-glow);
  animation: ringPop 0.6s var(--ease-spring);
}
@keyframes ringPop { from{transform:scale(0.5);opacity:0} to{transform:scale(1);opacity:1} }
.result-score-inner {
  width: 96px; height: 96px; border-radius: 50%;
  background: var(--bg2);
  display: flex; flex-direction: column; align-items: center; justify-content: center;
  border: 1px solid var(--border2);
}
.result-score-num { font-family: var(--font-head); font-size: 1.7rem; font-weight: 700; color: var(--cyan); }
.result-score-label { font-size: 0.6rem; color: var(--text3); text-transform: uppercase; letter-spacing: 0.1em; }
.result-xp { display: flex; align-items: center; justify-content: center; gap: 6px; margin: 14px 0; }
.result-xp-badge {
  background: var(--cyan-dim); border: 1px solid rgba(0,245,255,0.3);
  color: var(--cyan); padding: 7px 20px; border-radius: 99px;
  font-weight: 800; font-size: 1.2rem; font-family: var(--font-mono);
  box-shadow: 0 0 20px var(--cyan-dim);
  animation: xpPop 0.5s 0.3s var(--ease-spring) both;
}
@keyframes xpPop { from{transform:scale(0);opacity:0} to{transform:scale(1);opacity:1} }
.result-level-up {
  background: linear-gradient(135deg, rgba(255,179,0,0.1), rgba(255,45,155,0.08));
  border: 1px solid var(--amber);
  border-radius: var(--radius-lg); padding: 14px;
  color: var(--amber); font-weight: 800; font-size: 1rem;
  margin: 12px 0;
  animation: levelGlow 1s var(--ease) infinite alternate;
}
@keyframes levelGlow { from{box-shadow:0 0 10px rgba(255,179,0,0.2)} to{box-shadow:0 0 25px rgba(255,179,0,0.4)} }

/* ── Leaderboard ─────────────────────────────────────────── */
.leaderboard-wrap { max-width: 700px; }
.lb-podium {
  display: grid; grid-template-columns: 1fr 1.2fr 1fr;
  gap: 12px; margin-bottom: 24px; align-items: flex-end;
}
.lb-podium-card {
  background: var(--bg2); border: 1px solid var(--border2);
  border-radius: var(--radius-lg); padding: 16px 12px;
  text-align: center; position: relative; overflow: hidden;
  transition: all var(--t) var(--ease);
}
.lb-podium-card.first {
  background: linear-gradient(135deg, rgba(255,179,0,0.06), var(--bg2));
  border-color: var(--amber);
  box-shadow: 0 0 30px rgba(255,179,0,0.1);
}
.lb-rank { font-family: var(--font-head); font-size: 1.6rem; font-weight: 800; margin-bottom: 8px; }
.lb-name { font-weight: 700; font-size: 0.85rem; }
.lb-xp   { font-family: var(--font-mono); font-size: 0.75rem; color: var(--text2); margin-top: 3px; }

.lb-row {
  display: flex; align-items: center; gap: 12px;
  padding: 11px 14px; border-radius: var(--radius);
  background: var(--bg2); border: 1px solid var(--border);
  margin-bottom: 6px; transition: all var(--t) var(--ease);
}
.lb-row:hover { border-color: var(--border2); }
.lb-row.me {
  border-color: rgba(0,245,255,0.3);
  background: var(--cyan-dim);
  box-shadow: 0 0 16px var(--cyan-dim);
}
.lb-rank-num { font-family: var(--font-mono); font-size: 0.82rem; color: var(--text3); width: 26px; text-align: center; }
.lb-row-name { flex: 1; font-weight: 600; font-size: 0.88rem; }
.lb-row-xp   { font-family: var(--font-mono); font-size: 0.84rem; color: var(--cyan); font-weight: 600; }

/* ── Admin Table ─────────────────────────────────────────── */
.data-table { width: 100%; border-collapse: collapse; }
.data-table th {
  padding: 10px 14px; text-align: left;
  font-size: 0.68rem; text-transform: uppercase; letter-spacing: 0.1em;
  color: var(--text3); border-bottom: 1px solid var(--border);
  font-weight: 700;
}
.data-table td { padding: 12px 14px; font-size: 0.86rem; border-bottom: 1px solid var(--border); }
.data-table tr:last-child td { border-bottom: none; }
.data-table tr:hover td { background: rgba(0,245,255,0.02); }

/* ── Modal ───────────────────────────────────────────────── */
.modal-overlay {
  position: fixed; inset: 0; z-index: 500;
  background: rgba(0,0,0,0.8); backdrop-filter: blur(8px);
  display: flex; align-items: center; justify-content: center; padding: 20px;
}
.modal {
  background: var(--bg2); border: 1px solid var(--border2);
  border-radius: var(--radius-xl); padding: 28px;
  width: 100%; max-width: 520px; max-height: 90vh; overflow-y: auto;
  animation: modalIn 0.25s var(--ease-spring);
  box-shadow: var(--shadow-lg), 0 0 60px rgba(0,245,255,0.06);
  position: relative;
}
.modal::before {
  content: '';
  position: absolute; top: 0; left: 20%; right: 20%; height: 1px;
  background: linear-gradient(90deg, transparent, var(--cyan), transparent);
}
@keyframes modalIn { from{opacity:0;transform:scale(0.88)} to{opacity:1;transform:scale(1)} }
.modal-header { display: flex; align-items: center; justify-content: space-between; margin-bottom: 20px; }
.modal-title { font-family: var(--font-head); font-size: 1.2rem; font-weight: 700; letter-spacing: -0.02em; }
.modal-close {
  width: 30px; height: 30px; border-radius: 8px;
  background: var(--bg3); color: var(--text2); font-size: 0.9rem;
  display: flex; align-items: center; justify-content: center;
  cursor: pointer; transition: all var(--t) var(--ease); border: 1px solid var(--border);
}
.modal-close:hover { background: var(--red-dim); color: var(--red); border-color: rgba(255,61,113,0.3); }

/* ── Toast ───────────────────────────────────────────────── */
.toast-container { position: fixed; bottom: 24px; right: 24px; z-index: 9000; display: flex; flex-direction: column; gap: 8px; }
.toast {
  background: var(--bg2); border: 1px solid var(--border2);
  border-radius: var(--radius); padding: 12px 16px;
  display: flex; align-items: center; gap: 10px;
  font-size: 0.84rem; box-shadow: var(--shadow-lg);
  animation: toastIn 0.3s var(--ease-spring);
  min-width: 260px; max-width: 380px;
}
.toast-success { border-left: 3px solid var(--green); }
.toast-error   { border-left: 3px solid var(--red); }
.toast-info    { border-left: 3px solid var(--cyan); }
.toast-warning { border-left: 3px solid var(--amber); }
@keyframes toastIn { from{opacity:0;transform:translateX(20px) scale(0.95)} to{opacity:1;transform:translateX(0) scale(1)} }

/* ── Lesson Content ──────────────────────────────────────── */
.lesson-section {
  background: var(--bg2); border: 1px solid var(--border2);
  border-radius: var(--radius-lg); padding: 22px 24px;
  margin-bottom: 14px; position: relative; overflow: hidden;
}
.lesson-section::before {
  content: ''; position: absolute; top: 0; left: 0; bottom: 0; width: 3px;
  background: linear-gradient(180deg, var(--cyan), var(--magenta));
  border-radius: 3px 0 0 3px;
}
.lesson-section-type {
  display: inline-flex; align-items: center; gap: 5px;
  font-size: 0.65rem; text-transform: uppercase; letter-spacing: 0.12em;
  font-weight: 800; margin-bottom: 8px; padding: 3px 10px;
  border-radius: 99px;
}
.type-introduction { background: var(--blue-dim);   color: var(--blue); border: 1px solid rgba(41,121,255,0.2); }
.type-concept      { background: var(--cyan-dim);    color: var(--cyan); border: 1px solid rgba(0,245,255,0.2); }
.type-example      { background: var(--green-dim);   color: var(--green); border: 1px solid rgba(0,230,118,0.2); }
.type-summary      { background: var(--amber-dim);   color: var(--amber); border: 1px solid rgba(255,179,0,0.2); }
.lesson-section-title { font-family: var(--font-head); font-size: 1.05rem; font-weight: 700; margin-bottom: 10px; letter-spacing: -0.02em; }
.lesson-section-body { font-size: 0.9rem; line-height: 1.75; color: var(--text2); }
.lesson-section-body h1,.lesson-section-body h2,.lesson-section-body h3 { color: var(--cyan); font-weight: 700; margin: 14px 0 6px; }
.lesson-section-body strong { color: var(--text); }
.lesson-section-body code { background: var(--bg3); padding: 2px 6px; border-radius: 4px; font-family: var(--font-mono); font-size: 0.85em; color: var(--cyan); }
.lesson-section-body ul,.lesson-section-body ol { padding-left: 20px; margin: 8px 0; }

.lesson-fun-fact {
  background: linear-gradient(135deg, rgba(0,245,255,0.06), rgba(255,45,155,0.04));
  border: 1px solid rgba(0,245,255,0.15);
  border-radius: var(--radius-lg); padding: 16px 18px;
  display: flex; gap: 12px; align-items: flex-start; margin-bottom: 18px;
}
.key-term {
  background: var(--bg3); border: 1px solid var(--border2);
  border-radius: var(--radius); padding: 5px 12px; font-size: 0.8rem;
  cursor: pointer; transition: all var(--t) var(--ease); font-weight: 500;
}
.key-term:hover { border-color: var(--cyan); color: var(--cyan); background: var(--cyan-dim); }
.lesson-key-terms { display: flex; flex-wrap: wrap; gap: 7px; margin-bottom: 18px; }

/* ── Progress ────────────────────────────────────────────── */
.progress-bar { height: 6px; background: var(--bg4); border-radius: 99px; overflow: hidden; }
.progress-fill {
  height: 100%; border-radius: 99px;
  transition: width 0.7s var(--ease-out);
}

/* ── Empty State ─────────────────────────────────────────── */
.empty-state { text-align: center; padding: 60px 20px; }
.empty-state-icon { font-size: 3rem; margin-bottom: 12px; opacity: 0.5; display: block; }
.empty-state-title { font-size: 1rem; font-weight: 700; margin-bottom: 6px; }
.empty-state-text { font-size: 0.85rem; color: var(--text2); }

/* ── Loading ─────────────────────────────────────────────── */
.spinner {
  width: 26px; height: 26px; border-radius: 50%;
  border: 2.5px solid var(--bg4);
  border-top-color: var(--cyan);
  animation: spin 0.65s linear infinite;
  display: inline-block;
  box-shadow: 0 0 12px var(--cyan-dim);
}
@keyframes spin { to { transform: rotate(360deg); } }
.loading-page { display: flex; align-items: center; justify-content: center; gap: 12px; padding: 80px; color: var(--text2); font-size: 0.88rem; }

/* ── Scrollbars ──────────────────────────────────────────── */
::-webkit-scrollbar { width: 5px; height: 5px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--bg4); border-radius: 99px; }
::-webkit-scrollbar-thumb:hover { background: var(--border2); }

/* ── Responsive ──────────────────────────────────────────── */
@media (max-width: 900px) {
  .sidebar { transform: translateX(-100%); }
  .sidebar.open { transform: translateX(0); box-shadow: var(--shadow-lg); }
  .main { margin-left: 0; }
  .login-left { display: none; }
  .login-right { width: 100%; }
  .page { padding: 20px; }
  .form-row-2,.form-row-3 { grid-template-columns: 1fr; }
}
@media (max-width: 600px) {
  .tasks-grid { grid-template-columns: 1fr; }
  .diff-selector { flex-direction: column; align-items: center; }
  .diff-option { max-width: 100%; width: 100%; }
  .stats-grid { grid-template-columns: repeat(2, 1fr); }
  .lb-podium { grid-template-columns: 1fr; }
}

/* ── Glow utilities ──────────────────────────────────────── */
.glow-cyan { box-shadow: 0 0 20px var(--cyan-glow) !important; }
.glow-mg   { box-shadow: 0 0 20px var(--glow-mg) !important; }
.text-cyan { color: var(--cyan) !important; }
.text-mg   { color: var(--magenta) !important; }
.text-green{ color: var(--green) !important; }
.text-amber{ color: var(--amber) !important; }