/* EDU-SQL · SQL Playground — a distinct member of the EDU-* collection. Where
   EDU-REGEX evokes Olivetti's warm putty desktop, EDU-SQL evokes a 1970s
   mainframe operator console: a dark steel chassis, engraved labels, amber
   keycaps, and deep phosphor-green display insets for everything the machine
   "shows" — the tables, the pipeline, the result set, the event log. */

:root {
  --chassis: #1c2128;
  --chassis-deep: #14181d;
  --panel: #222831;
  --panel-2: #2a313b;
  --panel-edge: #3a434e;
  --ink: #cdd9e5;
  --ink-soft: #8b98a5;
  --amber: #e3b341;
  --amber-dark: #b8862a;
  --screen: #07130c;
  --screen-2: #0a1a10;
  --screen-edge: #030805;
  --phosphor: #57e389;
  --phosphor-dim: #3a9c63;
  --phosphor-soft: #9ff5c0;
  --pass: #57e389;
  --fail: #f0663f;
  --unknown: #c9a0dc;
  --mono: ui-monospace, "SF Mono", "Cascadia Mono", "JetBrains Mono", Menlo, Consolas, monospace;
  --sans: "Avenir Next", "Segoe UI", system-ui, -apple-system, sans-serif;
  /* group colours (GROUP BY clusters) */
  --g-0: #7ad4e8;
  --g-1: #e3b341;
  --g-2: #c9a0dc;
  --g-3: #f0a48a;
  --g-4: #57e389;
  --g-5: #e8e0a0;
}

* { box-sizing: border-box; margin: 0; padding: 0; }
[hidden] { display: none !important; }
html, body { height: 100%; }

body {
  font-family: var(--sans);
  color: var(--ink);
  background:
    radial-gradient(ellipse at 20% -10%, #262d36 0%, var(--chassis) 55%, var(--chassis-deep) 100%);
  display: flex;
  flex-direction: column;
}

button { font: inherit; cursor: pointer; }
a { color: var(--phosphor); }

/* ---------- header ---------- */

.top {
  display: flex; align-items: center; justify-content: space-between;
  gap: 1rem; padding: 0.7rem 1.2rem;
  border-bottom: 2px solid var(--panel-edge); flex-wrap: wrap;
  background: linear-gradient(#20262e, #1a1f26);
}
.brand { display: flex; align-items: center; gap: 0.75rem; }
.brand-mark {
  font-family: var(--mono); font-weight: 700; font-size: 0.85rem;
  color: var(--screen); background: var(--phosphor); border-radius: 6px;
  padding: 0.45rem 0.5rem; letter-spacing: 0.02em;
  box-shadow: 0 0 10px rgb(87 227 137 / 0.4), inset 0 -2px 0 rgb(0 0 0 / 0.25);
}
.brand-text h1 { font-family: var(--mono); font-size: 1.15rem; letter-spacing: 0.06em; line-height: 1.1; color: var(--ink); }
.brand-sub { font-size: 0.62rem; letter-spacing: 0.3em; color: var(--ink-soft); font-weight: 600; vertical-align: 0.15em; }
.brand-tag { font-size: 0.72rem; color: var(--ink-soft); font-style: italic; }
.top-nav { display: flex; align-items: center; gap: 0.5rem; }
.lang-switch { display: flex; border: 1px solid var(--panel-edge); border-radius: 6px; overflow: hidden; margin-left: 0.4rem; }
.lang-switch button { border: 0; background: var(--panel); color: var(--ink-soft); font-size: 0.7rem; font-weight: 700; letter-spacing: 0.08em; padding: 0.35rem 0.55rem; }
.lang-switch button.active { background: var(--phosphor); color: var(--screen); }

/* ---------- keycap buttons ---------- */

.btn {
  font-size: 0.78rem; font-weight: 600; letter-spacing: 0.06em; color: var(--ink);
  background: linear-gradient(#2f3742, #262d36); border: 1px solid var(--panel-edge);
  border-radius: 7px; padding: 0.42rem 0.85rem;
  box-shadow: 0 2px 0 #12161b, 0 3px 4px rgb(0 0 0 / 0.25);
  transition: transform 60ms, box-shadow 60ms; display: inline-block;
}
.btn:hover { filter: brightness(1.12); }
.btn:active { transform: translateY(2px); box-shadow: 0 0 0 #12161b; }
.btn:disabled { opacity: 0.4; cursor: default; transform: none; }
.btn-primary { color: var(--screen); background: linear-gradient(#f0c65a, var(--amber)); border-color: var(--amber-dark); box-shadow: 0 2px 0 var(--amber-dark), 0 3px 6px rgb(227 179 65 / 0.25); }
.btn-ghost { background: transparent; box-shadow: none; border-color: transparent; color: var(--ink-soft); }
.btn-ghost:active { transform: none; }
:focus-visible { outline: 2px solid var(--amber); outline-offset: 2px; }

/* ---------- cards & engraved labels ---------- */

.card {
  background: var(--panel); border: 1px solid var(--panel-edge); border-radius: 10px;
  box-shadow: 0 1px 0 rgb(255 255 255 / 0.03) inset, 0 6px 14px rgb(0 0 0 / 0.25);
  padding: 0.7rem 0.8rem 0.8rem;
}
.card-head { display: flex; align-items: center; justify-content: space-between; flex-wrap: wrap; gap: 0.5rem; margin-bottom: 0.55rem; }
.card-title, .lesson-eyebrow {
  font-size: 0.62rem; font-weight: 700; letter-spacing: 0.26em; text-transform: uppercase;
  color: var(--ink-soft);
}
.chip { border-radius: 4px; padding: 0.08rem 0.45rem; white-space: nowrap; }
.chip-rule { font-family: var(--mono); font-size: 0.68rem; background: var(--panel-2); border: 1px solid var(--panel-edge); color: var(--ink); }

/* ---------- lesson panel ---------- */

.lesson { display: flex; flex-direction: column; gap: 0.7rem; }
.lesson-eyebrow { display: flex; align-items: center; gap: 0.5rem; }
.lesson-title { font-size: 1.25rem; line-height: 1.2; color: var(--ink); }
.lesson-text { font-size: 0.86rem; line-height: 1.55; color: var(--ink); }
.lesson-text p + p { margin-top: 0.5rem; }
.lesson-text code, .goal code, .hint code, .help-body code {
  font-family: var(--mono); font-size: 0.85em; background: rgb(87 227 137 / 0.12);
  color: var(--phosphor-soft); border-radius: 4px; padding: 0.05em 0.3em;
}
.lesson-text pre, .help-body pre {
  font-family: var(--mono); font-size: 0.78rem; line-height: 1.5;
  background: var(--screen); color: var(--phosphor); border-radius: 7px;
  padding: 0.6rem 0.8rem; overflow-x: auto; margin: 0.4rem 0;
}
.goal { font-size: 0.86rem; line-height: 1.5; background: rgb(227 179 65 / 0.08); border-left: 3px solid var(--amber); border-radius: 0 7px 7px 0; padding: 0.5rem 0.7rem; }
.goal-label { display: block; font-size: 0.6rem; font-weight: 700; letter-spacing: 0.26em; text-transform: uppercase; color: var(--amber); margin-bottom: 0.15rem; }
.rule-chips { display: flex; flex-wrap: wrap; gap: 0.3rem; }
.hints { display: flex; flex-direction: column; gap: 0.4rem; align-items: flex-start; }
.hint { font-size: 0.82rem; line-height: 1.5; background: rgb(201 160 220 / 0.1); border-left: 3px solid var(--unknown); border-radius: 0 7px 7px 0; padding: 0.45rem 0.65rem; }
.banner { border-radius: 8px; padding: 0.7rem 0.8rem; font-size: 0.86rem; font-weight: 600; display: flex; flex-direction: column; gap: 0.55rem; }
.banner-pass { background: rgb(87 227 137 / 0.12); border: 1px solid var(--pass); color: var(--phosphor-soft); }
.banner-fail { background: rgb(240 102 63 / 0.12); border: 1px solid var(--fail); color: #f6a48a; }
.done-mark { color: var(--pass); font-weight: 700; }
.btn-hint { font-size: 0.72rem; border: 1px dashed var(--panel-edge); }

/* ---------- modals ---------- */

.overlay { position: fixed; inset: 0; background: rgb(5 8 5 / 0.65); display: flex; align-items: center; justify-content: center; padding: 1rem; z-index: 10; }
.modal { background: var(--panel); border: 1px solid var(--panel-edge); border-radius: 12px; box-shadow: 0 20px 60px rgb(0 0 0 / 0.5); max-width: 900px; width: 100%; max-height: 88vh; overflow-y: auto; padding: 1rem 1.2rem 1.2rem; }
.modal-head { display: flex; align-items: center; justify-content: space-between; margin-bottom: 0.8rem; }
.modal-head h2 { font-size: 1.1rem; letter-spacing: 0.02em; }
.level-cards { display: grid; grid-template-columns: repeat(auto-fill, minmax(190px, 1fr)); gap: 0.6rem; }
.level-card { position: relative; display: flex; flex-direction: column; align-items: flex-start; gap: 0.25rem; text-align: left; background: linear-gradient(#2b323c, #242a32); border: 1px solid var(--panel-edge); border-radius: 9px; padding: 0.7rem 0.8rem; box-shadow: 0 2px 0 #12161b; transition: transform 80ms; color: var(--ink); }
.level-card:hover { transform: translateY(-2px); }
.level-card.current { border-color: var(--amber); box-shadow: 0 2px 0 var(--amber-dark); }
.level-card .level-num { font-family: var(--mono); font-size: 0.7rem; font-weight: 700; color: var(--amber); letter-spacing: 0.1em; }
.level-card .level-name { font-weight: 600; font-size: 0.85rem; }
.level-card .level-desc { font-size: 0.72rem; color: var(--ink-soft); }
.level-card .done-mark { position: absolute; top: 0.55rem; right: 0.7rem; }
.level-card.done { border-color: var(--phosphor-dim); }
.sandbox-card { border-style: dashed; }
.help-body { font-size: 0.86rem; line-height: 1.55; }
.help-body h3 { font-size: 0.66rem; font-weight: 700; letter-spacing: 0.26em; text-transform: uppercase; color: var(--amber); margin: 1rem 0 0.4rem; }
.help-body p { margin-bottom: 0.5rem; }
.help-body table { border-collapse: collapse; width: 100%; font-size: 0.8rem; }
.help-body th, .help-body td { text-align: left; padding: 0.3rem 0.5rem; border-bottom: 1px solid var(--panel-edge); }
.help-body th { font-size: 0.62rem; letter-spacing: 0.2em; text-transform: uppercase; color: var(--ink-soft); }
.help-body td { vertical-align: top; }
.intro-foot { display: flex; justify-content: flex-end; margin-top: 1rem; }

/* ---------- workbench layout ---------- */

.workbench {
  flex: 1; display: grid;
  grid-template-columns: minmax(240px, 320px) minmax(460px, 1fr) minmax(300px, 380px);
  gap: 0.9rem; padding: 0.9rem 1.2rem 1.2rem; align-items: start;
  max-width: 1800px; width: 100%; margin: 0 auto;
}
.col-main, .col-inspect { display: flex; flex-direction: column; gap: 0.9rem; }
.toolbar { display: flex; align-items: center; gap: 0.4rem; flex-wrap: wrap; }
.speed { display: flex; align-items: center; gap: 0.4rem; font-size: 0.62rem; font-weight: 700; letter-spacing: 0.18em; text-transform: uppercase; color: var(--ink-soft); margin-left: 0.3rem; }
.speed input { width: 84px; accent-color: var(--amber); }

/* ---------- screen inset (shared) ---------- */

.netscreen { position: relative; background: var(--screen); border: 2px solid var(--screen-edge); border-radius: 8px; box-shadow: inset 0 2px 14px rgb(0 0 0 / 0.7); overflow: hidden; }
.netscreen::after { content: ''; position: absolute; inset: 0; background: repeating-linear-gradient(rgb(0 0 0 / 0.12) 0 1px, transparent 1px 3px); pointer-events: none; border-radius: 6px; z-index: 5; }

/* ---------- pipeline (phase indicator) ---------- */

.pipeline-host { display: flex; flex-wrap: wrap; gap: 0.25rem; align-items: stretch; }
.pl-stage {
  display: flex; flex-direction: column; align-items: center; gap: 0.1rem;
  font-family: var(--mono); font-size: 0.6rem; letter-spacing: 0.05em;
  color: var(--ink-soft); background: var(--panel-2); border: 1px solid var(--panel-edge);
  border-radius: 6px; padding: 0.28rem 0.5rem; min-width: 3.6rem; position: relative;
  transition: background 120ms, color 120ms, border-color 120ms;
}
.pl-stage .pl-name { font-weight: 700; text-transform: uppercase; }
.pl-stage .pl-count { font-size: 0.58rem; color: var(--phosphor-dim); min-height: 0.8em; }
.pl-stage.active { background: var(--amber); color: var(--screen); border-color: var(--amber); box-shadow: 0 0 12px rgb(227 179 65 / 0.5); }
.pl-stage.active .pl-count { color: var(--screen); }
.pl-stage.spent { border-color: var(--phosphor-dim); color: var(--phosphor); }
.pl-stage.spent .pl-count { color: var(--phosphor-dim); }
.pl-arrow { align-self: center; color: var(--ink-soft); font-size: 0.7rem; }

/* ---------- the tables (signature canvas) ---------- */

.tables-host { min-height: 200px; padding: 0.6rem; position: relative; }
.tables-wrap { position: relative; display: flex; flex-wrap: wrap; gap: 1rem; align-items: flex-start; z-index: 6; }
.db-table { position: relative; }
.db-caption { font-family: var(--mono); font-size: 0.62rem; letter-spacing: 0.18em; text-transform: uppercase; color: var(--phosphor-dim); margin-bottom: 0.25rem; }
.db-caption .db-idx { color: var(--amber); }
.db-grid { border-collapse: separate; border-spacing: 0; font-family: var(--mono); font-size: 0.74rem; color: var(--phosphor); }
.db-grid th { font-size: 0.62rem; color: var(--phosphor-dim); text-align: left; padding: 0.18rem 0.5rem; border-bottom: 1px solid rgb(87 227 137 / 0.25); font-weight: 700; }
.db-grid td { padding: 0.16rem 0.5rem; border-bottom: 1px solid rgb(87 227 137 / 0.08); white-space: nowrap; }
.db-grid td.tnull { color: var(--phosphor-dim); font-style: italic; }
.db-row { transition: background 110ms, opacity 140ms, box-shadow 110ms; }
.db-row .rid { color: var(--phosphor-dim); font-size: 0.6rem; }
.db-row.scanning { background: rgb(227 179 65 / 0.22); box-shadow: inset 3px 0 0 var(--amber); }
.db-row.kept { background: rgb(87 227 137 / 0.16); box-shadow: inset 3px 0 0 var(--pass); }
.db-row.dropped { opacity: 0.28; }
.db-row.unknown { background: rgb(201 160 220 / 0.16); box-shadow: inset 3px 0 0 var(--unknown); }
.db-row.joined { box-shadow: inset 3px 0 0 var(--phosphor-soft); }
.db-row.g-0 { box-shadow: inset 3px 0 0 var(--g-0); } .db-row.g-1 { box-shadow: inset 3px 0 0 var(--g-1); }
.db-row.g-2 { box-shadow: inset 3px 0 0 var(--g-2); } .db-row.g-3 { box-shadow: inset 3px 0 0 var(--g-3); }
.db-row.g-4 { box-shadow: inset 3px 0 0 var(--g-4); } .db-row.g-5 { box-shadow: inset 3px 0 0 var(--g-5); }
.db-empty { color: var(--phosphor-dim); font-family: var(--mono); font-size: 0.75rem; padding: 0.5rem; }

.join-arcs { position: absolute; inset: 0; z-index: 7; pointer-events: none; overflow: visible; }
.join-arc { fill: none; stroke: var(--phosphor); stroke-width: 1.4; stroke-opacity: 0.8; filter: drop-shadow(0 0 3px var(--phosphor)); }
.join-arc.nomatch { stroke: var(--fail); stroke-dasharray: 3 3; stroke-opacity: 0.7; filter: none; }

/* ---------- query editor ---------- */

.sql-editor { display: flex; flex-direction: column; gap: 0.4rem; }
.sql-field { background: var(--screen); border: 2px solid var(--screen-edge); border-radius: 8px; box-shadow: inset 0 2px 12px rgb(0 0 0 / 0.6); padding: 0.5rem 0.6rem; }
.sql-input {
  width: 100%; min-height: 4.5rem; resize: vertical; background: transparent; border: 0;
  color: var(--phosphor); caret-color: var(--phosphor-soft); font-family: var(--mono);
  font-size: 0.9rem; line-height: 1.45; text-shadow: 0 0 6px rgb(87 227 137 / 0.25);
}
.sql-input:focus { outline: none; }
.sql-input.has-error { color: #f6b8a4; }
.sql-squiggle { font-family: var(--mono); font-size: 0.75rem; border-left: 3px solid var(--fail); background: rgb(240 102 63 / 0.08); border-radius: 0 6px 6px 0; padding: 0.4rem 0.6rem; }
.sql-echo { color: var(--fail); white-space: pre; overflow-x: auto; margin-bottom: 0.2rem; }
.sql-errmsg { color: #f6a48a; font-weight: 600; }

.status-line { font-size: 0.78rem; color: var(--ink-soft); min-height: 1.3em; padding-top: 0.5rem; }
.status-line[data-kind="err"] { color: #f6a48a; font-weight: 600; }
.status-line[data-kind="ok"] { color: var(--phosphor); font-weight: 600; }

/* ---------- result panel ---------- */

.res-grid { width: 100%; border-collapse: collapse; font-family: var(--mono); font-size: 0.74rem; color: var(--phosphor); }
.res-grid th { font-size: 0.62rem; color: var(--phosphor-dim); text-align: left; padding: 0.2rem 0.5rem; border-bottom: 1px solid rgb(87 227 137 / 0.25); }
.res-grid td { padding: 0.16rem 0.5rem; border-bottom: 1px solid rgb(87 227 137 / 0.08); white-space: nowrap; }
.res-grid td.tnull { color: var(--phosphor-dim); font-style: italic; }
.res-grid tr.appear { animation: res-in 220ms ease-out; }
@keyframes res-in { from { background: rgb(87 227 137 / 0.35); } to { background: transparent; } }
.net-screenbox { background: var(--screen); border: 2px solid var(--screen-edge); border-radius: 7px; box-shadow: inset 0 2px 10px rgb(0 0 0 / 0.6); padding: 0.45rem 0.55rem; overflow-x: auto; min-height: 2.4em; }
.res-count { font-family: var(--mono); font-size: 0.66rem; color: var(--ink-soft); margin-bottom: 0.35rem; }

/* ---------- plan / inspector ---------- */

.net-tbl { width: 100%; border-collapse: collapse; font-family: var(--mono); font-size: 0.74rem; color: var(--phosphor); }
.net-tbl td { padding: 0.16rem 0.5rem 0.16rem 0; white-space: nowrap; }
.net-tbl td.k { color: var(--phosphor-dim); }
.plan-node { font-family: var(--mono); font-size: 0.72rem; color: var(--phosphor); padding: 0.12rem 0; }
.plan-node .op { color: var(--amber); font-weight: 700; }
.plan-node .op.seqscan { color: #f0a48a; }
.plan-node .op.indexscan { color: var(--phosphor); }
.lane-cmp { display: flex; gap: 0.5rem; flex-wrap: wrap; }
.lane-box { flex: 1 1 120px; background: var(--screen); border: 2px solid var(--screen-edge); border-radius: 7px; padding: 0.4rem 0.55rem; }
.lane-box .lane-name { font-size: 0.6rem; letter-spacing: 0.16em; text-transform: uppercase; color: var(--phosphor-dim); }
.lane-box .lane-rows { font-family: var(--mono); font-size: 1.1rem; color: var(--phosphor); }
.lane-box.win { border-color: var(--phosphor); box-shadow: 0 0 10px rgb(87 227 137 / 0.3); }
.tbl-empty { color: var(--phosphor-dim); font-family: var(--mono); font-size: 0.75rem; }

/* ---------- cases panel ---------- */

.cases { display: flex; flex-direction: column; gap: 0.4rem; }
.case-row { display: flex; justify-content: space-between; align-items: center; gap: 0.4rem; font-family: var(--mono); font-size: 0.7rem; background: var(--screen); color: var(--phosphor); border: 1px solid var(--screen-edge); border-radius: 5px; padding: 0.3rem 0.5rem; text-align: left; width: 100%; }
.case-row:hover { border-color: var(--phosphor-dim); }
.case-desc { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; color: var(--ink); }
.case-row.ok { border-color: var(--pass); }
.case-row.ok .case-mark { color: var(--pass); }
.case-row.bad { border-color: var(--fail); background: rgb(240 102 63 / 0.14); }
.case-row.bad .case-mark { color: var(--fail); }
.cases-note { font-size: 0.66rem; color: var(--ink-soft); font-style: italic; }

/* ---------- event log tape ---------- */

.evt-tape { background: var(--screen); border: 2px solid var(--screen-edge); border-radius: 7px; box-shadow: inset 0 2px 8px rgb(0 0 0 / 0.6); height: 200px; overflow-y: auto; font-family: var(--mono); font-size: 0.68rem; padding: 0.35rem 0.45rem; }
.evt-row { display: flex; align-items: baseline; gap: 0.4rem; padding: 0.05rem 0.15rem; color: var(--phosphor); white-space: nowrap; }
.evt-time { color: var(--phosphor-dim); flex: 0 0 2.6em; text-align: right; }
.evt-lane { color: var(--amber); flex: 0 0 auto; font-size: 0.6rem; }
.evt-phase { color: var(--amber); font-weight: 700; }
.evt-pass { color: var(--phosphor-soft); }
.evt-drop { color: #f0a48a; }
.evt-unknown { color: var(--unknown); }
.evt-group { color: var(--g-0); }
.evt-result { color: var(--phosphor); font-weight: 700; }
.evt-sub { color: var(--g-2); }

/* ---------- responsive ---------- */

@media (max-width: 1300px) {
  .workbench { grid-template-columns: minmax(230px, 300px) 1fr; }
  .col-inspect { grid-column: 1 / -1; flex-direction: row; flex-wrap: wrap; }
  .col-inspect .card { flex: 1 1 300px; }
}
@media (max-width: 820px) {
  .workbench { grid-template-columns: 1fr; padding: 0.7rem; }
  .col-inspect { flex-direction: column; }
}
@media (prefers-reduced-motion: reduce) {
  * { animation: none !important; transition: none !important; }
}