:root {
    --bg: #f5f6f8; --card: #ffffff; --text: #1d2330; --muted: #5d6677; --line: #dde1e8;
    --accent: #2457d6; --accent-soft: #e8eefc;
    --open: #fff4d6; --open-line: #e8a400; --open-text: #7a5600;
    --ok: #1f8a4c; --ok-soft: #e3f5ea; --err: #a32020; --err-soft: #fde8e8; --on-accent: #ffffff;
    color-scheme: light dark;
}
/* Review 4: dark mode like /evals/ */
@media (prefers-color-scheme: dark) {
    :root {
        --bg: #12151c; --card: #1c212b; --text: #e8ebf1; --muted: #9aa3b4; --line: #2e3542;
        --accent: #6d95ff; --accent-soft: #233257; --on-accent: #0d1530;
        --open: #3a2f12; --open-line: #c08a00; --open-text: #ffd27a;
        --ok: #5fd08f; --ok-soft: #173826; --err: #ff8b8b; --err-soft: #3d1c1c;
    }
}
* { box-sizing: border-box; }
body { margin: 0; font-family: "Segoe UI", system-ui, sans-serif; background: var(--bg); color: var(--text); }
main { max-width: 960px; margin: 0 auto; padding: 24px 16px 120px; }
h1 { font-size: 1.6rem; margin: 0 0 4px; }
.sub { color: var(--muted); margin: 0 0 16px; }
/* Review 4, C8: messages ok / err / warn / info like in evals.css, scans.css and duties.css */
.msg { padding: 12px 16px; border-radius: 10px; margin: 0 0 14px; overflow-wrap: anywhere; }
.msg.ok { background: var(--ok-soft); color: var(--ok); }
.msg.err { background: var(--err-soft); color: var(--err); }
.msg.info { background: var(--accent-soft); color: var(--text); }
.disclaimer { font-size: .9rem; color: var(--muted); background: var(--card); border: 1px solid var(--line); border-left: 4px solid var(--muted); border-radius: 8px; padding: 10px 14px; margin: 0 0 16px; }
.disclaimer strong { color: var(--text); }
.ask { background: var(--card); border: 1px solid var(--line); border-radius: 10px; padding: 20px; max-width: 480px; }
.ask label { display: block; font-weight: 600; margin-bottom: 8px; }
.ask .row { display: flex; gap: 8px; flex-wrap: wrap; }
.ask input[type=email] { flex: 1; min-width: 220px; padding: 10px 12px; font-size: 1rem; border: 1px solid var(--line); border-radius: 8px; }
.ask input[type=email]:focus { outline: 2px solid var(--accent); border-color: var(--accent); }
.ask p { color: var(--muted); font-size: .9rem; margin: 10px 0 0; }
.legend { display: flex; gap: 16px; flex-wrap: wrap; align-items: center; font-size: .9rem; color: var(--muted); margin-bottom: 8px; }
.legend .swatch { display: inline-block; width: 14px; height: 14px; border-radius: 3px; background: var(--open); border: 2px solid var(--open-line); vertical-align: -2px; margin-right: 6px; }
h2.day { font-size: 1.15rem; margin: 32px 0 12px; padding-bottom: 6px; border-bottom: 2px solid var(--line); }
.slot { background: var(--card); border: 1px solid var(--line); border-left: 6px solid var(--accent); border-radius: 10px; margin-bottom: 14px; padding: 14px 16px; }
.slot.open { background: var(--open); border-color: var(--open-line); }
.slot-head { display: flex; justify-content: space-between; align-items: baseline; gap: 12px; margin-bottom: 10px; }
.slot-time { font-weight: 600; font-size: 1.05rem; }
.badge { font-size: .8rem; font-weight: 600; padding: 2px 10px; border-radius: 999px; background: var(--open-line); color: var(--card); display: none; }
.slot.open .badge { display: inline-block; }
.options { display: grid; grid-template-columns: repeat(auto-fill, minmax(min(260px, 100%), 1fr)); gap: 8px; }
label.opt { display: flex; gap: 10px; align-items: flex-start; padding: 10px 12px; border: 1px solid var(--line); border-radius: 8px; background: var(--card); cursor: pointer; }
label.opt:hover { border-color: var(--accent); }
label.opt input { margin-top: 3px; flex: none; }
label.opt:has(input:checked) { border-color: var(--accent); background: var(--accent-soft); box-shadow: 0 0 0 1px var(--accent); }
.title { font-weight: 600; display: block; }
.speakers { color: var(--muted); font-size: .92rem; display: block; margin-top: 2px; }
.room { color: var(--muted); font-size: .8rem; display: block; margin-top: 4px; text-transform: uppercase; letter-spacing: .03em; }
label.opt.lightning .title::before { content: "\26A1  "; }
ul.talks { margin: 4px 0 0; padding-left: 18px; font-size: .9rem; }
ul.talks li { margin: 2px 0; }
.talk-title { font-weight: 500; }
.speakers-inline { color: var(--muted); }
label.opt.none .title { font-weight: 400; color: var(--muted); font-style: italic; }
.savebar { position: fixed; left: 0; right: 0; bottom: 0; background: var(--card); border-top: 1px solid var(--line); box-shadow: 0 -2px 12px rgba(0,0,0,.06); }
.savebar-inner { max-width: 960px; margin: 0 auto; padding: 12px 16px; display: flex; justify-content: space-between; align-items: center; gap: 12px; flex-wrap: wrap; }
.progress { color: var(--muted); }
.progress strong { color: var(--text); }
.progress a { color: var(--open-text); margin-left: 8px; }
/* Review 4, C13: buttons like evals.css */
.btn { display: inline-flex; align-items: center; justify-content: center; gap: 6px; background: var(--accent); color: var(--on-accent);
       border: 1px solid var(--accent); border-radius: 10px; padding: 10px 18px; font: inherit; font-size: 1rem; font-weight: 600;
       line-height: 1.45; cursor: pointer; text-decoration: none; -webkit-tap-highlight-color: transparent; }
.btn:hover { filter: brightness(1.08); }
.btn:disabled { opacity: .5; cursor: default; }
.logo { float: right; margin: 0 0 12px 16px; }
.logo img { display: block; max-height: 56px; max-width: 180px; }
.site-foot { clear: both; margin-top: 40px; padding-top: 14px; border-top: 1px solid var(--line); text-align: center; font-size: .92rem; }
.site-foot a { color: var(--accent); }
/* B6.14: slot as fieldset with legend (accessibility), without browser border */
fieldset.slot-set { border: 0; margin: 0; padding: 0; min-width: 0; }
fieldset.slot-set > legend { padding: 0; width: 100%; }
.when { color: var(--muted); font-size: .85rem; display: block; margin-top: 4px; font-variant-numeric: tabular-nums; }
/* Time of the selected session has changed since saving */
.moved { display: block; margin-top: 6px; font-size: .88rem; font-weight: 600; color: var(--open-text); background: var(--open); border: 1px solid var(--open-line); border-radius: 6px; padding: 4px 8px; }
.msg.warn { background: var(--open); color: var(--open-text); }
.unsaved { color: var(--open-text); font-weight: 600; margin-left: 12px; display: none; }
.unsaved.show { display: inline; }
/* Review 4, I14: calendar download and "Rate this session" */
.tools { display: flex; flex-wrap: wrap; gap: 8px 16px; align-items: center; margin: 0 0 16px; font-size: .92rem; color: var(--muted); }
a.btn { text-decoration: none; display: inline-flex; }
.btn.ghost { background: transparent; color: var(--accent); border-color: var(--accent); }
.btn.sm { padding: 4px 10px; font-size: .85rem; border-radius: 8px; }
.btn.danger { background: transparent; color: var(--err); border-color: var(--err); }
@media (pointer: coarse) { .btn.sm { min-height: 36px; padding: 6px 12px; } }
/* Issue #162 C11: "sign out" is a POST button that looks like a link */
.linkbtn { background: none; border: 0; padding: 0; font: inherit; color: var(--accent); text-decoration: underline; cursor: pointer; }
.rate { margin: 10px 0 0; font-size: .92rem; }
.rate a { color: var(--accent); font-weight: 600; }
/* Review 4, I15: privacy notice and "Delete my picks" */
.privacy { font-size: .85rem; color: var(--muted); margin: 24px 0 0; }
.privacy a { color: var(--accent); }
.ask .row a { align-self: center; color: var(--accent); }
/* Review 4: footer of all pages "Community Event Tools by … · Version …" (below the link to the conference) */
.credit { margin: 6px 0 0; text-align: center; font-size: .78rem; color: var(--muted); }
.site-foot .credit a { color: inherit; }

/* Review 5, C9: logo on a white, rounded background (otherwise invisible in dark mode), like evals.css header.top .logo */
.logo { background: #fff; border-radius: 10px; padding: 6px; }
/* Review 5, C8: neutral page "not open right now" like /evals/ (card, logo and name of the conference, no red message) */
.card { background: var(--card); border: 1px solid var(--line); border-radius: 14px; padding: 20px 22px; margin: 0 0 14px; }
.card.empty { max-width: 640px; margin: 32px auto 14px; text-align: center; padding: 32px 20px; color: var(--muted); clear: both; }
.card.empty h1 { color: var(--text); margin-bottom: 8px; }
.card.empty .logo { float: none; display: inline-block; margin: 0 0 14px; }
.card.empty p { margin: 0; }

/* Issue #54: "Open" badge with dark text on yellow (white on #e8a400 had only ~2.1:1; dark 7.6:1 or in
   dark mode 5.4:1 on #c08a00 – WCAG AA) */
:root { --on-open-line: #1d2330; }
.badge { color: var(--on-open-line); }
/* Issue #54: heading of the second step "Delete my picks" (was a <label> without an input field) */
.ask .ask-title { font-size: 1rem; font-weight: 600; margin: 0 0 8px; }
/* Issue #54: save bar above the home indicator (safe area); compact on the phone: text on the left (lines stacked),
   button on the right, so that it does not become ~130 px high and cover the privacy notice and footer */
main { padding-bottom: calc(120px + env(safe-area-inset-bottom)); }
.savebar-inner { padding-bottom: calc(12px + env(safe-area-inset-bottom)); }
/* Issue #136: opt-in for change mails, between progress and button */
.savebar .notify { display: flex; align-items: center; gap: 6px; font-size: .9rem; cursor: pointer; }
.savebar .notify input { width: 18px; height: 18px; margin: 0; flex: none; }
@media (max-width: 600px) {
    .savebar-inner { flex-wrap: nowrap; gap: 10px; padding: 8px 12px calc(8px + env(safe-area-inset-bottom)); }
    .progress { flex: 1 1 auto; min-width: 0; font-size: .88rem; line-height: 1.35; }
    .progress a { display: block; margin-left: 0; }
    .unsaved { margin-left: 0; }
    .unsaved.show { display: block; }
    .savebar .btn { flex: none; padding: 10px 14px; }
    .savebar .notify { flex: 0 1 auto; font-size: .8rem; line-height: 1.25; max-width: 40%; }
}

/* Issue #77: categories as small tags and the abstract behind "Details" (native <details>, no script). "Details" sits
   below the option's <label> (otherwise a click on it would select the session); both together look like one card. */
.tags { display: flex; flex-wrap: wrap; gap: 4px; margin-top: 6px; }
.tag-cat { font-size: .75rem; line-height: 1.4; padding: 1px 8px; border-radius: 999px; background: var(--bg); color: var(--muted); border: 1px solid var(--line); }
ul.talks .tags { margin-top: 2px; }
.optwrap { display: flex; flex-direction: column; min-width: 0; }
.optwrap > label.opt { flex: 1 1 auto; border-bottom-left-radius: 0; border-bottom-right-radius: 0; }
.optwrap > details.abstract { border: 1px solid var(--line); border-top: 0; border-radius: 0 0 8px 8px; background: var(--card); padding: 6px 12px 8px; }
details.abstract summary { cursor: pointer; color: var(--accent); font-weight: 600; font-size: .88rem; }
details.abstract summary:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
.abstract-text { margin-top: 6px; font-size: .9rem; line-height: 1.5; overflow-wrap: anywhere; }
.abstract-text p { margin: 0 0 8px; }

/* Issue #71: language switch EN | DE (top right, small) */
.lang-switch { text-align: right; font-size: .85rem; color: var(--muted); margin: 0 0 8px; }
.lang-switch a { color: var(--accent); font-weight: 600; text-decoration: none; padding: 4px 2px; }
.lang-switch a:hover, .lang-switch a:focus-visible { text-decoration: underline; }
.lang-switch strong { color: var(--text); }

/* Issue #151: live notices (schedule changes and the organizer's notice) at the top of the page */
.live-notices { margin: 0 0 14px; padding: 10px 14px; border-radius: 10px; border-left: 4px solid var(--accent); background: var(--accent-soft); color: var(--text); overflow-wrap: anywhere; }
.live-notices .ln-title { margin: 0 0 4px; font-weight: 700; font-size: .8rem; letter-spacing: .06em; text-transform: uppercase; color: var(--accent); }
.live-notices .ln-own { margin: 0 0 6px; font-weight: 600; }
.live-notices ul { margin: 0; padding-left: 18px; }
.live-notices li { margin: 2px 0; }
.live-notices .ln-more { margin: 4px 0 0; font-size: .9rem; color: var(--muted); }