/* ============================================================
   VINTAGE OLD PAPER — FLAT UI
   Font: Reddit Sans · Icon: Font Awesome · No radius/shadow/gradient
   Palette lấy cảm hứng giấy cũ + mực sepia, tương phản chuẩn WCAG
   ============================================================ */

:root {
  /* giấy */
  --paper:      #f1e7cf;   /* nền chính */
  --paper-2:    #e9dcbe;   /* panel */
  --paper-3:    #dfd0a9;   /* header bảng / vùng nhấn */
  --paper-4:    #f7f0de;   /* sân khấu (sáng nhất — figure) */
  /* mực */
  --ink:        #2e2416;   /* chữ chính — 12.9:1 trên paper */
  --ink-soft:   #5b4a30;   /* chữ phụ — 7.2:1 */
  --ink-faint:  #8a7654;   /* chữ mờ — 4.6:1 */
  /* viền */
  --line:       #a8925f;
  --line-soft:  #c9b98c;
  /* màu nhấn kiểu mực in cũ */
  --amber:      #b0791f;   /* highlight */
  --amber-bg:   #f3dd9d;
  --green:      #44602f;   /* 6.4:1 trên paper */
  --green-bg:   #dfe4c2;
  --red:        #96392b;   /* 6.5:1 trên paper */
  --red-bg:     #ecd2c3;
  --blue:       #34576e;   /* 6.9:1 trên paper */
  --blue-bg:    #d9e0e0;
  --font: 'Reddit Sans', 'Segoe UI', system-ui, sans-serif;
}

* { margin: 0; padding: 0; box-sizing: border-box; border-radius: 0 !important; box-shadow: none !important; }

html, body { height: 100%; }
body {
  font-family: var(--font);
  font-size: 16px;
  color: var(--ink);
  background: var(--paper);
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

/* khung viền đôi kiểu giấy tờ cũ quanh toàn trang */
body::before {
  content: '';
  position: fixed; inset: 6px;
  border: 1px solid var(--line);
  outline: 1px solid var(--line-soft);
  outline-offset: 3px;
  pointer-events: none;
  z-index: 999;
}

/* ================= HEADER ================= */
header {
  display: flex; align-items: center; justify-content: space-between;
  gap: 16px;
  padding: 12px 26px;
  background: var(--paper-2);
  border-bottom: 2px solid var(--ink);
  flex-wrap: wrap;
}
.brand {
  font-size: 20px; font-weight: 800; letter-spacing: .02em;
  display: flex; align-items: center; gap: 10px; flex-wrap: wrap;
}
.brand > i { color: var(--amber); font-size: 22px; }
.brand .sep { color: var(--ink-faint); font-weight: 400; }
.badge-sql {
  font-size: 13px; font-weight: 700; letter-spacing: .08em; text-transform: uppercase;
  border: 1px solid var(--ink);
  padding: 3px 10px;
  background: var(--paper-4);
  display: inline-flex; align-items: center; gap: 7px;
}
.badge-sql i { color: var(--blue); }

.transport { display: flex; align-items: center; gap: 8px; flex-wrap: wrap; }
.transport button {
  font-family: var(--font);
  font-size: 15px; font-weight: 600;
  height: 36px; padding: 0 16px; gap: 8px;
  background: var(--paper-4);
  color: var(--ink);
  border: 1px solid var(--ink);
  cursor: pointer;
  display: inline-flex; align-items: center; justify-content: center;
  transition: background .15s, color .15s;
}
.transport button:hover { background: var(--ink); color: var(--paper-4); }
.transport button:active { background: var(--amber); border-color: var(--amber); }
.speed-ico { color: var(--ink-soft); font-size: 15px; margin-left: 6px; }
#speed {
  font-family: var(--font); font-size: 15px; font-weight: 600;
  background: var(--paper-4); color: var(--ink);
  border: 1px solid var(--ink);
  padding: 6px 8px; cursor: pointer;
}

/* ================= PROGRESS ================= */
#progress {
  position: relative;
  height: 34px;
  background: var(--paper);
  border-bottom: 1px solid var(--line);
  display: flex; align-items: center; justify-content: center; gap: 8px;
}
#progressFill {
  position: absolute; left: 0; top: 0; height: 3px;
  background: var(--amber);
  transition: width .4s;
}
#progressSteps { display: flex; gap: 8px; }
.pdot {
  width: 26px; height: 26px;
  border: 1px solid var(--line);
  background: var(--paper-4);
  color: var(--ink-soft);
  font-size: 13px; font-weight: 700;
  display: flex; align-items: center; justify-content: center;
  cursor: pointer;
  transition: background .15s, color .15s, border-color .15s;
}
.pdot:hover { border-color: var(--ink); }
.pdot.done { background: var(--ink); color: var(--paper-4); border-color: var(--ink); }
.pdot.current { background: var(--amber-bg); color: var(--ink); border: 2px solid var(--amber); }

/* ================= LAYOUT CHÍNH (gestalt: enclosure + proximity) ================= */
main {
  flex: 1; min-height: 0;
  display: grid;
  grid-template-columns: 340px 1fr;
  gap: 0;
}

/* --- panel SQL (trái) --- */
#sqlpanel {
  background: var(--paper-2);
  border-right: 1px solid var(--line);
  padding: 16px;
  display: flex; flex-direction: column; gap: 12px;
  overflow: auto;
  scrollbar-gutter: stable; /* giữ chỗ scrollbar cố định — layout không nhảy khi đóng/mở challenge */
}
.panel-title {
  font-size: 14px; font-weight: 800;
  text-transform: uppercase; letter-spacing: .12em;
  color: var(--ink-soft);
  border-bottom: 2px solid var(--ink);
  padding-bottom: 7px;
  display: flex; align-items: center; gap: 9px;
}
.panel-title i { color: var(--amber); }

#challenge {
  background: var(--paper-4);
  border: 1px solid var(--line);
}
#challenge summary {
  font-size: 14px; font-weight: 800;
  text-transform: uppercase; letter-spacing: .12em;
  color: var(--ink-soft);
  border-bottom: 2px solid var(--ink);
  padding: 0 10px 7px;
  display: flex; align-items: center; gap: 9px;
  cursor: pointer; list-style: none;
}
#challenge summary::-webkit-details-marker { display: none; }
#challenge summary::after {
  content: '\f0d8'; /* fa-chevron-up — đang mở */
  font-family: 'Font Awesome 6 Free'; font-weight: 900;
  margin-left: auto; font-size: 12px; color: var(--ink-faint);
}
#challenge:not([open]) summary { border-bottom-color: transparent; padding-bottom: 0; }
#challenge:not([open]) summary::after { content: '\f0d7'; } /* fa-chevron-down */
#challenge:not([open]) .challenge-body { display: none; }
#challenge summary i { color: var(--amber); }
.challenge-body {
  font-size: 14.5px; line-height: 1.55;
  padding: 10px 12px 12px;
  display: flex; flex-direction: column; gap: 8px;
}
.challenge-body p { color: var(--ink); }
.schema-name { font-weight: 800; color: var(--blue); display: flex; align-items: center; gap: 7px; }
.schema-name i { color: var(--amber); font-size: 13px; }
.schema { border-collapse: collapse; width: 100%; }
.schema td { border: 1px solid var(--line-soft); padding: 4px 9px; font-size: 13.5px; }
.schema td:last-child { color: var(--ink-soft); text-align: right; }

#sqlcode {
  font-family: var(--font);
  font-size: 14px; line-height: 1.55;
  white-space: pre-wrap; overflow-wrap: break-word;
  background: var(--paper-4);
  border: 1px solid var(--line);
  padding: 12px;
}
#sqlcode .tok { display: block; padding: 4px 6px; border-left: 3px solid transparent; transition: background .25s, border-color .25s; }
#sqlcode .tok.hl { background: var(--amber-bg); border-left-color: var(--amber); }
#sqlcode .kw { font-weight: 800; color: var(--blue); }
#sqlcode .fn { font-weight: 700; color: var(--red); }

/* --- sân khấu (giữa) --- */
#stagewrap {
  position: relative;
  overflow: auto;
  background: var(--paper);
  padding: 14px;
}
#stage {
  position: relative;
  width: 100%; min-height: 100%;
  background: var(--paper-4);
  border: 1px solid var(--line);
  overflow: auto;
  padding-bottom: 24px;
}



/* ================= FOOTER ================= */
footer {
  background: var(--paper-2);
  border-top: 2px solid var(--ink);
  padding: 12px 26px;
  min-height: 58px;
  display: flex; align-items: center;
}
#subtitle { font-size: 16.5px; line-height: 1.55; max-width: 1100px; }
#subtitle b { font-weight: 800; }
#subtitle .g { color: var(--green); font-weight: 700; }
#subtitle .r { color: var(--red); font-weight: 700; }
#subtitle .y { color: var(--amber); font-weight: 700; }

/* ================= PHẦN TỬ TRÊN SÂN KHẤU ================= */
.step-title {
  position: absolute; left: 18px; top: 12px; right: 18px;
  font-size: 22px; font-weight: 800;
  color: var(--ink);
  border-bottom: 2px solid var(--ink);
  padding-bottom: 7px;
  white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
  z-index: 5;
}

/* --- bảng dữ liệu --- */
.tbl { position: absolute; background: transparent; }
.tbl-name {
  font-size: 14px; font-weight: 800;
  letter-spacing: .04em;
  background: var(--paper-3);
  border: 1px solid var(--ink);
  border-bottom: none;
  padding: 5px 10px;
  display: flex; align-items: center; justify-content: space-between; gap: 12px;
}
.tbl-name .cnt {
  font-size: 12px; font-weight: 700;
  color: var(--paper-4);
  background: var(--ink);
  padding: 1px 8px;
}
.tbl table { border-collapse: collapse; background: var(--paper-4); border: 1px solid var(--ink); }
.tbl th {
  font-size: 13px; font-weight: 800; text-transform: uppercase; letter-spacing: .06em;
  background: var(--paper-3);
  border: 1px solid var(--line);
  padding: 5px 12px;
  color: var(--ink);
}
.tbl td {
  font-size: 14.5px;
  border: 1px solid var(--line-soft);
  padding: 4px 12px;
  text-align: center;
  font-variant-numeric: tabular-nums;
}
.tbl tr:nth-child(even) td { background: var(--paper); }
.tbl tr.row-hl td { background: var(--amber-bg); }
.tbl tr.row-ok td { background: var(--green-bg); color: var(--green); font-weight: 700; }
.tbl tr.row-bad td { background: var(--red-bg); color: var(--red); font-weight: 700; }
.tbl tr.row-dim td { opacity: .38; }
.tbl-compact .tbl-name { font-size: 13px; padding: 4px 8px; }
.tbl-compact th { font-size: 12px; padding: 4px 9px; }
.tbl-compact td { font-size: 13.5px; padding: 3px 9px; }

/* --- nhóm GROUP BY --- */
.gbox {
  position: absolute;
  border: 2px dashed var(--blue);
  background: rgba(217, 224, 224, .35);
  z-index: 2;
}
.glabel {
  position: absolute; top: -11px; left: 10px;
  font-size: 12.5px; font-weight: 800;
  background: var(--blue); color: var(--paper-4);
  padding: 1px 9px;
  letter-spacing: .04em;
}

/* --- chip bay --- */
.chip {
  position: absolute;
  font-size: 14px; font-weight: 700;
  padding: 4px 10px;
  border: 1px solid var(--ink);
  background: var(--paper-4);
  color: var(--ink);
  z-index: 20;
  white-space: nowrap;
}
.chip.c-date { background: var(--blue-bg); border-color: var(--blue); color: var(--blue); }
.chip.c-min { background: var(--green-bg); border-color: var(--green); color: var(--green); }
.chip.c-eq { background: var(--green-bg); border-color: var(--green); color: var(--green); }
.chip.c-neq { background: var(--red-bg); border-color: var(--red); color: var(--red); }

/* --- vùng chứa (zone) --- */
.zone {
  position: absolute;
  border: 1px dashed var(--line);
  background: var(--paper);
  z-index: 1;
}
.zlabel {
  position: absolute; top: -11px; left: 10px;
  font-size: 12px; font-weight: 800; text-transform: uppercase; letter-spacing: .1em;
  background: var(--paper-3);
  border: 1px solid var(--line);
  color: var(--ink-soft);
  padding: 1px 9px;
}

/* --- nhãn mũi tên / chú thích --- */
.arrow-label {
  position: absolute;
  font-size: 14.5px; font-weight: 600;
  color: var(--ink);
  background: var(--paper-2);
  border: 1px solid var(--line);
  border-left: 4px solid var(--amber);
  padding: 6px 12px;
  z-index: 10;
  max-width: 480px;
}
.caption {
  position: absolute;
  font-size: 13.5px; font-style: italic;
  color: var(--ink-soft);
  z-index: 10;
}

/* --- hộp index --- */
.idx-box {
  position: absolute;
  background: var(--paper-4);
  border: 1px solid var(--ink);
  padding: 10px 14px;
  font-size: 14.5px; line-height: 1.7;
  z-index: 10;
}
.idx-key {
  font-weight: 800;
  background: var(--blue-bg);
  border: 1px solid var(--blue);
  color: var(--blue);
  padding: 1px 8px;
  margin-right: 6px;
  font-size: 13px;
}

/* --- verdict TRUE/FALSE --- */
.verdict {
  position: absolute;
  font-size: 16px; font-weight: 800;
  padding: 6px 14px;
  border: 2px solid;
  z-index: 20;
  display: flex; align-items: center; gap: 8px;
  white-space: nowrap;
}
.verdict.v-ok { background: var(--green-bg); border-color: var(--green); color: var(--green); }
.verdict.v-bad { background: var(--red-bg); border-color: var(--red); color: var(--red); }

/* --- thẻ kết luận --- */
.card {
  position: absolute;
  background: var(--paper-4);
  border: 1px solid var(--ink);
  padding: 12px 16px;
  font-size: 15.5px; line-height: 1.55;
  z-index: 15;
  max-width: 460px;
}
.card.good { border-left: 6px solid var(--green); }
.card .note { font-size: 14px; color: var(--ink-soft); }
.card .gv { color: var(--green); font-weight: 800; font-size: 18px; }

/* --- codebox so sánh (bước SARGable) --- */
.codebox {
  position: absolute;
  font-size: 15px; line-height: 1.7;
  background: var(--paper-4);
  border: 1px solid var(--ink);
  padding: 12px 16px;
  z-index: 10;
  max-width: 440px;
}
.codebox.bad { border-left: 6px solid var(--red); }
.codebox.good { border-left: 6px solid var(--green); }
.codebox .kw { font-weight: 800; color: var(--blue); }
.codebox .fn { font-weight: 700; color: var(--red); }
.codebox u { text-decoration-thickness: 2px; text-underline-offset: 3px; }

/* --- thẻ lý do (bước 3 lý do ở quy mô lớn) --- */
.reason {
  position: absolute;
  display: flex; gap: 12px;
  background: var(--paper-4);
  border: 1px solid var(--ink);
  border-left: 6px solid var(--amber);
  padding: 12px 16px;
  z-index: 10;
  max-width: 560px;
}
.reason .rnum {
  flex: 0 0 30px; width: 30px; height: 30px;
  display: flex; align-items: center; justify-content: center;
  background: var(--amber); color: var(--paper-4);
  font-weight: 800; font-size: 16px;
}
.reason .rbody { font-size: 15px; line-height: 1.5; }
.reason .rbody .note { font-size: 13.5px; color: var(--ink-soft); margin-top: 3px; }
.stream-row {
  position: absolute;
  display: flex; gap: 8px; align-items: center; flex-wrap: wrap;
  z-index: 10; max-width: 640px;
}
.stream-row .sk {
  font-weight: 800; font-size: 13px;
  background: var(--blue-bg); border: 1px solid var(--blue); color: var(--blue);
  padding: 3px 10px;
}
.stream-row .sarr { color: var(--ink-faint); font-weight: 700; }

/* --- kết quả lớn --- */
.big-result {
  position: absolute;
  text-align: center;
  z-index: 10;
}
.big-result .frac { display: inline-flex; flex-direction: column; align-items: center; vertical-align: middle; }
.big-result .num, .big-result .den { font-size: 56px; font-weight: 800; line-height: 1.05; }
.big-result .bar { width: 64px; height: 4px; background: var(--ink); margin: 6px 0; }
.big-result .eq-val {
  display: inline-block; vertical-align: middle;
  font-size: 46px; font-weight: 800;
  margin-left: 22px;
  color: var(--green);
}
.big-result .pct { font-size: 26px; color: var(--ink-soft); font-weight: 700; }
.big-result .cap {
  margin-top: 14px;
  font-size: 15.5px; color: var(--ink-soft);
  border-top: 1px solid var(--line);
  padding-top: 10px;
}

/* --- flow recap --- */
.flow {
  position: static;
  margin-top: 64px;
  display: flex; flex-wrap: wrap; align-items: center; justify-content: center;
  gap: 10px;
  padding: 20px 24px;
}
.fnode {
  background: var(--paper-4);
  border: 1px solid var(--ink);
  padding: 12px 16px;
  min-width: 130px;
  text-align: center;
}
.fnode.final { border: 2px solid var(--green); background: var(--green-bg); }
.fname { font-size: 15.5px; font-weight: 800; }
.frows { font-size: 13.5px; color: var(--ink-soft); margin-top: 3px; }
.fnode.final .frows { color: var(--green); font-weight: 700; }
.farrow { text-align: center; min-width: 96px; }
.farrow > div:first-child { font-size: 12.5px; font-weight: 700; color: var(--ink-soft); margin-bottom: 2px; }
.farrow-ico { font-size: 20px; color: var(--amber); }

/* ================= ANIMATION (flat — không dùng shadow/glow) ================= */
@keyframes popIn { from { opacity: 0; transform: scale(.7); } to { opacity: 1; transform: scale(1); } }
.anim-pop { animation: popIn .4s cubic-bezier(.34, 1.4, .64, 1) both; }

@keyframes fadeIn { from { opacity: 0; } to { opacity: 1; } }
.anim-fade { animation: fadeIn .5s ease both; }

@keyframes glowPulse {
  0%, 100% { background-color: var(--amber-bg); }
  50% { background-color: var(--paper-4); }
}
.anim-glow { animation: glowPulse 1.1s ease 2; }
tr.anim-glow td { animation: glowPulse 1.1s ease 2; }

/* ================= RESPONSIVE ================= */
@media (max-width: 1200px) {
  main { grid-template-columns: 300px 1fr; }
}
@media (max-width: 980px) {
  main { grid-template-columns: 260px 1fr; }
  .brand { font-size: 17px; }
  .step-title { font-size: 19px; }
}
@media (max-width: 720px) {
  main { grid-template-columns: 1fr; grid-template-rows: auto 1fr; }
  #sqlpanel { max-height: 220px; border-right: none; border-bottom: 1px solid var(--line); }
  header { padding: 10px 14px; }
  footer { padding: 10px 14px; }
  #subtitle { font-size: 14.5px; }
  .pdot { width: 22px; height: 22px; font-size: 11px; }
  .step-title { font-size: 17px; }
  .big-result .num, .big-result .den { font-size: 42px; }
  .big-result .eq-val { font-size: 34px; }
}