/* ============================================================
   SkillTutor AI - dark theme, purple gradient, mobile-first
   ============================================================ */
:root {
  --bg: #0f0b1e;
  --bg-2: #15102b;
  --card: #1b1437;
  --card-2: #221a44;
  --border: #2e2553;
  --text: #ece9f7;
  --muted: #a79fc9;
  --primary: #8b5cf6;
  --primary-2: #6d28d9;
  --accent: #c084fc;
  --good: #34d399;
  --bad: #fb7185;
  --warn: #fbbf24;
  --radius: 16px;
  --shadow: 0 10px 30px rgba(0,0,0,.35);
  --grad: linear-gradient(135deg, #8b5cf6 0%, #6d28d9 50%, #4c1d95 100%);
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
  background: radial-gradient(1200px 600px at 80% -10%, #2a1b5e 0%, transparent 60%), var(--bg);
  color: var(--text);
  font-family: "Inter", system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
}
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }
h1, h2, h3 { line-height: 1.2; }
img { max-width: 100%; }

.container { max-width: 1080px; margin: 0 auto; padding: 0 20px; }

/* ---------- Buttons ---------- */
.btn {
  display: inline-block; cursor: pointer; border: 0; border-radius: 999px;
  padding: 12px 22px; font-weight: 600; font-size: 15px; color: #fff;
  background: var(--grad); box-shadow: var(--shadow); transition: transform .08s ease;
  text-decoration: none;
}
.btn:hover { transform: translateY(-1px); text-decoration: none; }
.btn--ghost { background: transparent; border: 1px solid var(--border); color: var(--text); box-shadow: none; }
.btn--block { display: block; width: 100%; text-align: center; }
.btn--sm { padding: 7px 14px; font-size: 13px; }
.btn--danger { background: linear-gradient(135deg,#fb7185,#be123c); }

/* ---------- Cards ---------- */
.card {
  background: linear-gradient(180deg, var(--card-2), var(--card));
  border: 1px solid var(--border); border-radius: var(--radius);
  padding: 22px; box-shadow: var(--shadow);
}
.card h2, .card h3 { margin-top: 0; }
.grid { display: grid; gap: 18px; }
.grid--2 { grid-template-columns: repeat(2, 1fr); }
.grid--3 { grid-template-columns: repeat(3, 1fr); }
.grid--4 { grid-template-columns: repeat(4, 1fr); }
@media (max-width: 880px) {
  .grid--2, .grid--3, .grid--4 { grid-template-columns: 1fr; }
}

/* ---------- Stat tiles ---------- */
.stat { text-align: left; }
.stat__value { font-size: 30px; font-weight: 800; background: var(--grad); -webkit-background-clip: text; background-clip: text; color: transparent; }
.stat__label { color: var(--muted); font-size: 13px; margin-top: 4px; }

/* ---------- Forms ---------- */
.field { margin-bottom: 16px; }
.field label { display: block; font-size: 13px; color: var(--muted); margin-bottom: 6px; }
.input, select, textarea {
  width: 100%; padding: 12px 14px; border-radius: 12px; border: 1px solid var(--border);
  background: var(--bg-2); color: var(--text); font-size: 15px; font-family: inherit;
}
.input:focus, select:focus, textarea:focus { outline: 2px solid var(--primary); border-color: var(--primary); }
textarea { resize: vertical; min-height: 90px; }

/* ---------- Flash ---------- */
.flash { padding: 12px 16px; border-radius: 12px; margin-bottom: 16px; font-size: 14px; }
.flash--success { background: rgba(52,211,153,.12); border: 1px solid var(--good); color: #b9f5dd; }
.flash--error   { background: rgba(251,113,133,.12); border: 1px solid var(--bad); color: #ffd0d6; }
.flash--info    { background: rgba(139,92,246,.12); border: 1px solid var(--primary); color: #ddd1ff; }

/* ---------- Tables ---------- */
.table { width: 100%; border-collapse: collapse; }
.table th, .table td { padding: 11px 12px; text-align: left; border-bottom: 1px solid var(--border); font-size: 14px; }
.table th { color: var(--muted); font-weight: 600; }
.badge { display: inline-block; padding: 3px 10px; border-radius: 999px; font-size: 12px; background: var(--card-2); border: 1px solid var(--border); }
.badge--good { color: var(--good); border-color: var(--good); }
.badge--bad  { color: var(--bad); border-color: var(--bad); }
.badge--warn { color: var(--warn); border-color: var(--warn); }

/* ---------- Auth pages ---------- */
.auth { min-height: 100vh; display: grid; place-items: center; padding: 30px 16px; }
.auth__card { width: 100%; max-width: 420px; }
.auth__brand { text-align: center; font-weight: 800; font-size: 22px; margin-bottom: 4px; }
.auth__sub { text-align: center; color: var(--muted); margin-bottom: 22px; font-size: 14px; }
.muted { color: var(--muted); }
.center { text-align: center; }

/* ---------- Dashboard shell ---------- */
.app { display: grid; grid-template-columns: 250px 1fr; min-height: 100vh; }
.sidebar {
  background: var(--bg-2); border-right: 1px solid var(--border);
  padding: 20px 14px; display: flex; flex-direction: column; gap: 6px;
}
.brand { font-weight: 800; font-size: 19px; color: var(--text); padding: 6px 10px; }
.sidebar__panel { font-size: 12px; text-transform: uppercase; letter-spacing: .08em; color: var(--muted); padding: 8px 10px; }
.sidebar__nav { display: flex; flex-direction: column; gap: 4px; }
.navlink { display: block; padding: 11px 12px; border-radius: 10px; color: var(--muted); font-size: 14px; }
.navlink:hover { background: var(--card); color: var(--text); text-decoration: none; }
.navlink--active { background: var(--grad); color: #fff; }
.navlink--logout { margin-top: auto; color: var(--bad); }
.content { display: flex; flex-direction: column; min-width: 0; }
.topbar { display: flex; align-items: center; justify-content: space-between; padding: 16px 26px; border-bottom: 1px solid var(--border); }
.topbar__title { font-size: 20px; margin: 0; }
.topbar__user { display: flex; align-items: center; gap: 10px; }
.avatar { width: 34px; height: 34px; border-radius: 50%; background: var(--grad); display: grid; place-items: center; font-weight: 700; }
.bell { position: relative; font-size: 18px; text-decoration: none; }
.bell:hover { text-decoration: none; }
.bell__badge { position: absolute; top: -6px; right: -8px; background: var(--bad); color: #fff; font-size: 10px; font-weight: 700; border-radius: 999px; padding: 1px 5px; }
.notif { padding: 12px 14px; border-radius: 12px; border: 1px solid var(--border); margin-bottom: 10px; background: var(--card-2); }
.notif--unread { border-color: var(--primary); }
.snap-result dt { color: var(--muted); font-size: 13px; margin-top: 10px; }
.snap-result dd { margin: 2px 0 0; }
.page { padding: 26px; }

@media (max-width: 760px) {
  .app { grid-template-columns: 1fr; }
  .sidebar { flex-direction: row; flex-wrap: wrap; align-items: center; }
  .sidebar__panel { display: none; }
  .sidebar__nav { flex-direction: row; flex-wrap: wrap; }
  .navlink--logout { margin-top: 0; }
}

/* ---------- Landing ---------- */
.nav { display: flex; align-items: center; justify-content: space-between; padding: 22px 0; }
.nav__links { display: flex; gap: 18px; align-items: center; }
.hero { text-align: center; padding: 70px 0 50px; }
.hero h1 { font-size: 46px; margin: 0 0 16px; }
.hero .grad { background: var(--grad); -webkit-background-clip: text; background-clip: text; color: transparent; }
.hero p { font-size: 19px; color: var(--muted); max-width: 640px; margin: 0 auto 28px; }
.section { padding: 50px 0; }
.section h2 { text-align: center; font-size: 32px; margin-bottom: 8px; }
.section .lead { text-align: center; color: var(--muted); margin-bottom: 34px; }
.feature { padding: 22px; }
.feature h3 { margin: 0 0 6px; }
.price-card { text-align: center; }
.price { font-size: 40px; font-weight: 800; }
.price small { font-size: 15px; color: var(--muted); font-weight: 400; }
.price-card ul { list-style: none; padding: 0; margin: 18px 0; text-align: left; }
.price-card li { padding: 7px 0; border-bottom: 1px solid var(--border); font-size: 14px; }
.price-card--featured { outline: 2px solid var(--primary); }
.faq { margin-bottom: 14px; }
.faq summary { cursor: pointer; font-weight: 600; padding: 14px 0; }
footer.site { border-top: 1px solid var(--border); padding: 30px 0; color: var(--muted); text-align: center; margin-top: 40px; }
@media (max-width: 760px) { .hero h1 { font-size: 32px; } .nav__links a:not(.btn) { display: none; } }

/* ---------- Marketing landing ---------- */
.lnav { position: sticky; top: 0; z-index: 50; background: rgba(15,11,30,.82); backdrop-filter: blur(10px); border-bottom: 1px solid var(--border); }
.lnav__inner { display: flex; align-items: center; justify-content: space-between; padding: 14px 0; }
.lnav__links { display: flex; align-items: center; gap: 18px; }
.lnav__links a { color: var(--muted); font-size: 14px; }
.lnav__links a:hover { color: var(--text); text-decoration: none; }
@media (max-width: 860px) { .lnav__links a:not(.btn) { display: none; } }

.lhero { padding: 56px 0 30px; }
.lhero__grid { display: grid; grid-template-columns: 1.05fr .95fr; gap: 40px; align-items: center; }
.lhero__copy h1 { font-size: 48px; margin: 14px 0 16px; }
.lhero__copy p { font-size: 19px; color: var(--muted); margin: 0 0 24px; max-width: 540px; }
.lhero__cta { display: flex; gap: 12px; flex-wrap: wrap; margin-bottom: 12px; }
.pill { display: inline-block; padding: 6px 14px; border-radius: 999px; background: var(--card-2); border: 1px solid var(--border); font-size: 12px; letter-spacing: .04em; color: var(--accent); }
@media (max-width: 860px) { .lhero__grid { grid-template-columns: 1fr; } .lhero__art { order: -1; } .lhero__copy h1 { font-size: 34px; } }

.chatcard { background: linear-gradient(180deg, var(--card-2), var(--card)); border: 1px solid var(--border); border-radius: 20px; padding: 18px; box-shadow: var(--shadow); display: flex; flex-direction: column; gap: 10px; }
.chatcard__head { display: flex; align-items: center; gap: 6px; color: var(--muted); font-size: 13px; padding-bottom: 8px; border-bottom: 1px solid var(--border); margin-bottom: 4px; }
.chatcard__head .dot { width: 9px; height: 9px; border-radius: 50%; background: var(--border); display: inline-block; }
.chatcard .msg { max-width: 88%; }
.lhero__img { width: 100%; border-radius: 20px; border: 1px solid var(--border); box-shadow: var(--shadow); display: block; }

.section--alt { background: var(--bg-2); }
.stepnum { width: 38px; height: 38px; border-radius: 50%; background: var(--grad); color: #fff; display: grid; place-items: center; font-weight: 800; margin-bottom: 10px; }
.ticks { list-style: none; padding: 0; margin: 18px 0 24px; }
.ticks li { padding: 8px 0 8px 30px; position: relative; }
.ticks li::before { content: "✓"; position: absolute; left: 0; color: var(--good); font-weight: 800; }
.band { background: var(--grad); }
.band h2, .band .lead { color: #fff; }
.band .lead { opacity: .92; }
.band .btn { background: #fff; color: var(--primary-2); }

.lfooter { display: grid; grid-template-columns: 2fr 1fr 1fr; gap: 24px; text-align: left; }
.lfooter strong { display: block; color: var(--text); margin-bottom: 10px; }
.lfooter a { display: block; color: var(--muted); padding: 4px 0; font-size: 14px; }
@media (max-width: 760px) { .lfooter { grid-template-columns: 1fr; } }

/* ---------- AI Tutor chat ---------- */
.chat { display: flex; flex-direction: column; height: calc(100vh - 200px); min-height: 420px; }
.chat__log { flex: 1; overflow-y: auto; padding: 10px; display: flex; flex-direction: column; gap: 14px; }
.msg { max-width: 80%; padding: 12px 16px; border-radius: 16px; white-space: pre-wrap; font-size: 15px; }
.msg--user { align-self: flex-end; background: var(--grad); color: #fff; border-bottom-right-radius: 4px; }
.msg--assistant { align-self: flex-start; background: var(--card-2); border: 1px solid var(--border); border-bottom-left-radius: 4px; }
.chat__form { display: flex; gap: 10px; padding-top: 14px; border-top: 1px solid var(--border); }
.chat__form textarea { min-height: 48px; }
.chip { display: inline-block; padding: 6px 12px; border-radius: 999px; background: var(--card-2); border: 1px solid var(--border); font-size: 13px; margin: 0 6px 6px 0; cursor: pointer; }
.chip:hover { border-color: var(--primary); }
.progress-bar { background: var(--bg-2); border-radius: 999px; height: 10px; overflow: hidden; border: 1px solid var(--border); }
.progress-bar > span { display: block; height: 100%; background: var(--grad); }