:root {
    --font: -apple-system, BlinkMacSystemFont, "Segoe UI", system-ui, Roboto, Helvetica, Arial, sans-serif;
    --bg: #F4F7F5; --surface: #fff; --surface-2: #FBFCFB;
    --ink: #14201B; --ink-2: #4A5A54; --ink-3: #7C8C86;
    --accent: #0E7C66; --accent-2: #0A5E4D; --accent-ink: #fff; --accent-soft: #E3F1EB;
    --border: #E2E7E4; --border-2: #CFD6D2; --lock: #9AA6A1;
    --warn: #A96A05; --warn-soft: #FAEFDA;
    --shadow-sm: 0 1px 2px rgba(20,32,27,.06);
    --shadow: 0 1px 2px rgba(20,32,27,.05), 0 10px 28px rgba(20,32,27,.07);
    --radius: 14px; --radius-sm: 9px;
}
@media (prefers-color-scheme: dark) {
    :root {
        --bg: #0C1310; --surface: #141E1A; --surface-2: #101815;
        --ink: #E8EEEB; --ink-2: #A7B4AE; --ink-3: #74827C;
        --accent: #2FBE9E; --accent-2: #57D3B6; --accent-ink: #06130F; --accent-soft: #14302A;
        --border: #26312C; --border-2: #33403A; --lock: #5C6A64;
        --warn: #E0A64B; --warn-soft: #271F12;
        --shadow-sm: 0 1px 2px rgba(0,0,0,.4);
        --shadow: 0 1px 2px rgba(0,0,0,.4), 0 14px 32px rgba(0,0,0,.4);
    }
}

* { box-sizing: border-box; }
body { margin: 0; background: var(--bg); color: var(--ink); font-family: var(--font); line-height: 1.5; -webkit-font-smoothing: antialiased; }
h1, h2, h3, h4 { margin: 0; letter-spacing: -.01em; text-wrap: balance; }
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

/* ---- top bar (studente) ---- */
.topbar { display: flex; align-items: center; justify-content: space-between; padding: 13px clamp(16px, 4vw, 40px); background: var(--surface); border-bottom: 1px solid var(--border); }
.brand { display: inline-flex; align-items: center; gap: 9px; }
.brand .mark { width: 26px; height: 26px; border-radius: 8px; background: linear-gradient(150deg, var(--accent), var(--accent-2)); color: #fff; display: grid; place-items: center; font-size: 14px; }
.brand .wm { font-weight: 750; }
.who { display: flex; align-items: center; gap: 14px; }
.who .nm { font-size: 13.5px; color: var(--ink-2); font-weight: 600; }
.linkbtn { background: none; border: 1px solid var(--border-2); color: var(--ink-2); border-radius: 999px; padding: 6px 14px; font: inherit; font-size: 13px; cursor: pointer; }
.linkbtn:hover { border-color: var(--accent); color: var(--accent); }

.wrap { max-width: 1080px; margin: 0 auto; }
.body { padding: clamp(20px, 4vw, 40px); }
.body > h2 { font-size: 22px; }
.body > .sub { color: var(--ink-2); font-size: 14px; margin: 6px 0 22px; }

.banner-wait { background: var(--warn-soft); color: var(--warn); border: 1px solid color-mix(in srgb, var(--warn) 30%, transparent); border-radius: var(--radius); padding: 14px 16px; margin-bottom: 22px; font-size: 14px; }

/* ---- level grid ---- */
.grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(230px, 1fr)); gap: 16px; }
.level { border: 1px solid var(--border); border-radius: var(--radius); background: var(--surface); overflow: hidden; box-shadow: var(--shadow-sm); color: inherit; }
a.level.open { transition: transform .12s, box-shadow .12s, border-color .12s; }
a.level.open:hover { transform: translateY(-3px); box-shadow: var(--shadow); border-color: var(--border-2); text-decoration: none; }
.thumb { aspect-ratio: 16/9; display: grid; place-items: center; font-size: 30px; color: #fff; position: relative; }
.t1 { background: linear-gradient(140deg, #0E7C66, #0A5E4D); }
.t2 { background: linear-gradient(140deg, #1C6E8C, #124A5E); }
.t3 { background: linear-gradient(140deg, #6A4FA3, #46356E); }
.t4 { background: linear-gradient(140deg, #B4762A, #7E5115); }
.badge-img { max-height: 76%; max-width: 46%; object-fit: contain; filter: drop-shadow(0 2px 7px rgba(0, 0, 0, .3)); }
.level.locked .thumb { filter: grayscale(1) opacity(.55); }
.level.locked .badge-img { filter: blur(5px); }
.level.locked { background: var(--surface-2); }
.lockbadge { position: absolute; inset: 0; display: grid; place-items: center; background: color-mix(in srgb, var(--surface) 45%, transparent); font-size: 24px; }
.meta { padding: 13px 15px 15px; }
.meta h3 { font-size: 15px; }
.card-desc { color: var(--ink-3); font-size: 12.5px; line-height: 1.45; margin-top: 6px; }
.meta .row { display: flex; align-items: center; justify-content: space-between; margin-top: 10px; }
.pill { font-size: 11.5px; font-weight: 650; padding: 3px 9px; border-radius: 999px; }
.pill.count { background: var(--accent-soft); color: var(--accent); }
.pill.lock { background: color-mix(in srgb, var(--lock) 18%, transparent); color: var(--ink-3); }
.go { font-size: 13px; font-weight: 650; color: var(--accent); }

/* ---- course / lesson lists ---- */
.crumb { display: flex; align-items: center; gap: 7px; font-size: 12.5px; color: var(--ink-3); margin-bottom: 16px; flex-wrap: wrap; }
.sec { font-size: 13px; text-transform: uppercase; letter-spacing: .05em; color: var(--ink-3); margin: 22px 0 8px; }
.ll { list-style: none; margin: 0; padding: 0; display: flex; flex-direction: column; gap: 4px; }
.ll li { padding: 11px 13px; border: 1px solid var(--border); border-radius: var(--radius-sm); background: var(--surface); font-size: 14px; }
.ll li.cur { background: var(--accent-soft); border-color: transparent; }
.ll li a { color: var(--ink); }
.ll-sub { display: block; color: var(--ink-3); font-size: 12.5px; margin-top: 2px; }

/* ---- lesson page ---- */
.lesson-wrap { display: grid; grid-template-columns: 1fr 300px; gap: 24px; }
@media (max-width: 820px) { .lesson-wrap { grid-template-columns: 1fr; } }
.player { aspect-ratio: 16/9; border-radius: var(--radius); overflow: hidden; border: 1px solid var(--border); background: #0c0f14; }
.player iframe { width: 100%; height: 100%; border: 0; display: block; }
.player.empty { display: grid; place-items: center; color: rgba(255,255,255,.6); font-size: 14px; }
.lesson-title { font-size: 20px; margin: 18px 0 8px; }
.lesson-sub { color: var(--ink-2); font-size: 14.5px; font-weight: 600; margin-top: 2px; }
.teachers { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 12px; }
.teacher { display: inline-flex; align-items: center; gap: 7px; padding: 4px 11px 4px 4px; border-radius: 999px; background: var(--surface-2); font-size: 12.5px; color: var(--ink-2); }
.teacher-ph { width: 24px; height: 24px; border-radius: 50%; object-fit: cover; }
.lesson-desc { color: var(--ink-2); font-size: 14px; }
.att { margin-top: 22px; }
.att h4 { font-size: 12.5px; text-transform: uppercase; letter-spacing: .06em; color: var(--ink-3); margin-bottom: 10px; }
.file { display: flex; align-items: center; gap: 12px; padding: 11px 13px; border: 1px solid var(--border); border-radius: var(--radius-sm); background: var(--surface); margin-bottom: 9px; color: var(--ink); }
.file:hover { border-color: var(--accent); text-decoration: none; }
.file .fico { width: 32px; height: 32px; border-radius: 8px; background: var(--accent-soft); color: var(--accent); display: grid; place-items: center; }
.file .fn { font-weight: 600; font-size: 13.5px; }
.file .fs { margin-left: auto; color: var(--ink-3); font-size: 12px; }
.side h4 { font-size: 12.5px; text-transform: uppercase; letter-spacing: .06em; color: var(--ink-3); margin-bottom: 12px; }

/* ---- auth (guest) ---- */
.auth-bg { min-height: 100vh; display: flex; align-items: center; justify-content: center; padding: 24px;
    background: radial-gradient(120% 80% at 100% 0%, color-mix(in srgb, var(--accent) 12%, transparent), transparent 60%), var(--surface-2); }
.card { width: 100%; max-width: 400px; background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); box-shadow: var(--shadow); padding: 30px 28px; }
.card h1 { font-size: 20px; margin-top: 18px; }
.muted { color: var(--ink-3); font-size: 13px; margin-top: 6px; }
.field { display: block; margin-top: 15px; font-size: 13px; font-weight: 600; color: var(--ink-2); }
.input { width: 100%; margin-top: 6px; padding: 11px 13px; border: 1px solid var(--border-2); border-radius: var(--radius-sm); background: var(--surface); color: var(--ink); font-size: 14.5px; }
.input:focus-visible { outline: 2px solid var(--accent); outline-offset: 1px; border-color: var(--accent); }
.inline { display: inline-flex; align-items: center; gap: 7px; margin-top: 12px; font-size: 13px; color: var(--ink-2); font-weight: 500; }
.btn { display: inline-flex; align-items: center; justify-content: center; width: 100%; margin-top: 20px; padding: 12px 16px; border: 0; border-radius: var(--radius-sm); background: var(--accent); color: var(--accent-ink); font-size: 14.5px; font-weight: 650; cursor: pointer; }
.btn:hover { background: var(--accent-2); }
.err { color: #C0392B; font-size: 12.5px; margin-top: 6px; }
.hint { margin-top: 16px; font-size: 12.5px; color: var(--ink-3); text-align: center; }
@media (prefers-color-scheme: dark) { .err { color: #F09488; } }

/* ---- logo Progetto Fenice (trasparente, swap per tema) ---- */
.brand-logo { text-align: center; }
.logo-lg { display: block; width: 150px; height: auto; margin: 2px auto 14px; }
.logo-home { display: block; width: 104px; height: auto; margin: 0 auto 12px; }
.logo-sm { height: 44px; width: 44px; object-fit: contain; flex: none; }
a.brand { text-decoration: none; }
a.brand:hover { text-decoration: none; }
.sep { margin-top: 18px; padding-top: 14px; border-top: 1px solid var(--border); }
.domanda { font-size: 16px; font-weight: 650; margin: 4px 0 16px; }