:root {
  --bg: #fafaf9; --card: #ffffff; --line: #e7e5e4; --tile: #f4f4f3; --text: #1c1917; --muted: #78716c;
  --accent: #2f5bd3; --accent-soft: #e8eefc; --ok: #15803d; --warn: #b45309; --radius: 14px;
}
* { box-sizing: border-box; }
html, body { margin: 0; background: var(--bg); color: var(--text);
  font: 16px/1.5 -apple-system, BlinkMacSystemFont, "Segoe UI", "Helvetica Neue", Arial, "PingFang SC", sans-serif; }
.wrap { max-width: 1480px; margin: 0 auto; padding: 24px 16px 64px; }
.narrow { max-width: 640px; }
h1 { font-size: 26px; margin: 8px 0 4px; font-weight: 650; }
h2 { font-size: 20px; margin: 0 0 12px; font-weight: 600; color: #44403c; }
p { margin: 8px 0; }
.muted { color: var(--muted); font-size: 14px; }
.card { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 20px 24px; }
.eyebrow { color: var(--muted); font-size: 14px; margin-bottom: 6px; }
.prompt { font-size: 17px; margin: 0 0 14px; }
.prompt b { font-weight: 600; }
.btn { appearance: none; border: 1px solid var(--line); background: #fff; color: var(--text); border-radius: 10px;
  padding: 10px 18px; font-size: 15px; cursor: pointer; }
.btn:hover { border-color: #a8a29e; }
.btn.primary { background: var(--accent); color: #fff; border-color: var(--accent); }
.btn.primary:disabled { background: #b8c4e8; border-color: #b8c4e8; cursor: not-allowed; }
.btn.small { padding: 4px 10px; font-size: 13px; }
input.id { font-size: 22px; letter-spacing: 3px; padding: 10px 14px; width: 100%; border: 1px solid var(--line);
  border-radius: 10px; text-transform: uppercase; }
input.id:focus { outline: 2px solid var(--accent-soft); border-color: var(--accent); }
.err { color: #b91c1c; font-size: 14px; min-height: 20px; }
.topbar { display: flex; align-items: center; justify-content: space-between; gap: 12px; margin-bottom: 16px; flex-wrap: wrap; }
.progress { flex: 1; min-width: 200px; height: 6px; background: var(--line); border-radius: 3px; overflow: hidden; }
.progress > div { height: 100%; background: var(--accent); transition: width .3s; }

/* Part 1: five videos */
.grid5 { display: grid; gap: 10px; grid-template-columns: repeat(5, minmax(0, 1fr)); }
@media (max-width: 1200px) { .grid5 { grid-template-columns: repeat(3, minmax(0, 1fr)); } }
@media (max-width: 760px)  { .grid5 { grid-template-columns: repeat(2, minmax(0, 1fr)); } }
@media (max-width: 480px)  { .grid5 { grid-template-columns: 1fr; } }
.grid2 { display: grid; gap: 14px; grid-template-columns: repeat(2, minmax(0, 1fr)); }
@media (max-width: 640px)  { .grid2 { grid-template-columns: 1fr; } }
.tile { background: var(--tile); border-radius: 12px; padding: 8px; border: 2px solid transparent; }
.tile.ranked { border-color: var(--accent-soft); }
.tile video { width: 100%; aspect-ratio: 832 / 464; display: block; border-radius: 8px; background: #ddd; cursor: zoom-in; }
.tile .lab { display: flex; justify-content: space-between; align-items: center; margin: 6px 2px 4px; font-weight: 600; }
.ranks { display: flex; gap: 4px; }
.ranks button { flex: 1; border: 1px solid var(--line); background: #fff; border-radius: 8px; padding: 6px 0;
  font-size: 15px; cursor: pointer; color: var(--text); }
.ranks button.on { background: var(--accent); color: #fff; border-color: var(--accent); }
.ranks button:hover:not(.on) { border-color: #a8a29e; }
.rankhint { display: flex; justify-content: space-between; font-size: 12px; color: var(--muted); margin: 2px 2px 0; }
.question { margin: 16px 0 6px; font-size: 16px; }
.choices { display: flex; gap: 10px; flex-wrap: wrap; margin: 10px 0 4px; }
.choices .btn.on { background: var(--accent); color: #fff; border-color: var(--accent); }
.actions { display: flex; justify-content: space-between; align-items: center; gap: 12px; margin-top: 18px; flex-wrap: wrap; }

/* zoom overlay */
.zoom { position: fixed; inset: 0; background: rgba(0,0,0,.82); display: none; align-items: center; justify-content: center; z-index: 10; padding: 16px; }
.zoom.on { display: flex; }
.zoom video { max-width: min(1400px, 100%); max-height: 90vh; border-radius: 10px; background: #000; }
.zoom .close { position: absolute; top: 14px; right: 18px; color: #fff; font-size: 30px; cursor: pointer; background: none; border: 0; }
ol.steps { padding-left: 20px; } ol.steps li { margin: 6px 0; }

/* ranking box (Part 1) */
.rankbox { border: 2px dashed #c7d2f0; background: #f7f9ff; border-radius: 12px; padding: 12px; margin-top: 4px; }
.rankrow { display: grid; grid-template-columns: repeat(5, minmax(0, 1fr)); gap: 10px; }
.slot { position: relative; height: 64px; border-radius: 10px; background: #fff; border: 1px solid #dbe2f5;
  display: flex; align-items: center; justify-content: center; transition: background .15s, border-color .15s; }
.slot .pos { position: absolute; top: 4px; left: 8px; font-size: 12px; color: var(--muted); font-weight: 600; }
.slot.over { background: var(--accent-soft); border-color: var(--accent); }
.slot.filled { border-color: #aebde8; }
.rankends { display: flex; justify-content: space-between; font-size: 13px; color: var(--muted); margin: 6px 4px 0; }
.rankends span:first-child::before { content: "← "; } .rankends span:last-child::after { content: " →"; }
.pool { display: flex; gap: 10px; align-items: center; flex-wrap: wrap; min-height: 64px; margin-top: 12px; padding: 8px 4px; }
.chip { width: 48px; height: 48px; border-radius: 10px; background: var(--accent); color: #fff; font-weight: 700; font-size: 20px;
  display: flex; align-items: center; justify-content: center; cursor: grab; user-select: none; touch-action: none;
  box-shadow: 0 1px 3px rgba(0,0,0,.15); }
.chip.dragging { opacity: .3; }
.chip.ghost { position: fixed; z-index: 20; pointer-events: none; cursor: grabbing; box-shadow: 0 6px 18px rgba(0,0,0,.25); }
.tile .badge { background: var(--accent); color: #fff; border-radius: 6px; padding: 0 7px; font-size: 13px; }
.tile .badge:empty { display: none; }
.tile .vlab { font-size: 18px; }
@media (max-width: 480px) { .slot { height: 56px; } .chip { width: 42px; height: 42px; font-size: 18px; } .rankrow { gap: 6px; } }
@media (max-width: 480px) { .grid5 { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 6px; } .tile { padding: 4px; } .tile .vlab { font-size: 15px; } }