/* Layout: a single exam-sheet column under a sticky control strip; passages set in 명조 like a printed test, answers revealed in red grading ink. */
:root {
  --paper: #f6f7f5;
  --sheet: #ffffff;
  --ink: #1b2130;
  --ink-soft: #545c6e;
  --rule: #c9cdd6;
  --rule-soft: #e4e7ec;
  --pen: #2547a0;        /* blue answer pen: UI accent */
  --pen-soft: #e8edf9;
  --red: #b5302a;        /* grading ink: answers */
  --red-soft: #fbefed;
  --font-text: "Nanum Myeongjo", "Noto Serif KR", "AppleMyungjo", "Batang", serif;
  --font-ui: "IBM Plex Sans KR", "Apple SD Gothic Neo", "Malgun Gothic", system-ui, sans-serif;
  --font-num: "IBM Plex Mono", ui-monospace, "SFMono-Regular", Menlo, monospace;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --paper: #12151c; --sheet: #191d26; --ink: #e5e8ef; --ink-soft: #9aa2b4;
    --rule: #3a4150; --rule-soft: #272c37; --pen: #8fa8ec; --pen-soft: #1f2840;
    --red: #f08a80; --red-soft: #2c1c1c; color-scheme: dark;
  }
}
:root[data-theme="dark"] {
  --paper: #12151c; --sheet: #191d26; --ink: #e5e8ef; --ink-soft: #9aa2b4;
  --rule: #3a4150; --rule-soft: #272c37; --pen: #8fa8ec; --pen-soft: #1f2840;
  --red: #f08a80; --red-soft: #2c1c1c; color-scheme: dark;
}
* { box-sizing: border-box; }
body { background: var(--paper); color: var(--ink); font-family: var(--font-ui); font-size: 15px; line-height: 1.6; }
body::before { content: ""; position: fixed; inset: 0 0 auto; height: env(safe-area-inset-top, 0px); z-index: 10; background: var(--sheet); }
button { font: inherit; color: inherit; cursor: pointer; }
button:focus-visible, textarea:focus-visible, select:focus-visible { outline: 2px solid var(--pen); outline-offset: 2px; }

.bar { position: sticky; top: env(safe-area-inset-top, 0px); z-index: 5; background: var(--sheet); border-bottom: 1px solid var(--rule);
  padding-left: max(16px, env(safe-area-inset-left, 0px)); padding-right: max(16px, env(safe-area-inset-right, 0px)); }
.bar-in { max-width: 880px; margin: 0 auto; display: flex; flex-wrap: wrap; align-items: center; gap: 10px 14px; padding-block: 10px; }
.brand { font-weight: 700; font-size: 15px; letter-spacing: -0.01em; margin-right: auto; }
.brand small { display: block; font-weight: 500; font-size: 12px; color: var(--ink-soft); letter-spacing: 0; }
.ctrl { display: flex; align-items: center; gap: 8px; flex-wrap: wrap; }
.btn { border: 1px solid var(--rule); background: var(--sheet); border-radius: 6px; padding: 6px 12px; font-size: 14px; font-weight: 500; }
.btn:hover { border-color: var(--pen); }
.btn[aria-pressed="true"] { background: var(--red-soft); border-color: var(--red); color: var(--red); }
.btn.pen { background: var(--pen); border-color: var(--pen); color: var(--sheet); }
.timer { font-family: var(--font-num); font-variant-numeric: tabular-nums; font-size: 18px; min-width: 4.2em; text-align: right; }
.timer.low { color: var(--red); }
select.sel { font: inherit; font-size: 14px; font-weight: 600; border: 1px solid var(--rule); border-radius: 6px; padding: 6px 8px; background: var(--sheet); color: var(--ink); }

.picker { max-width: 880px; margin: 0 auto; display: grid; grid-template-columns: repeat(10, minmax(0, 1fr)); gap: 6px; padding-block: 0 12px; }
.picker button { border: 1px solid var(--rule-soft); background: transparent; border-radius: 5px; padding: 5px 0; font-family: var(--font-num); font-size: 13px; font-variant-numeric: tabular-nums; }
.picker button.on { border-color: var(--pen); background: var(--pen-soft); color: var(--pen); font-weight: 700; }
.picker button:disabled { opacity: .35; cursor: default; }

main { padding-left: max(16px, env(safe-area-inset-left, 0px)); padding-right: max(16px, env(safe-area-inset-right, 0px)); padding-block: 24px 64px; }
.sheet { max-width: 880px; margin: 0 auto; background: var(--sheet); border: 1px solid var(--rule); padding: clamp(18px, 4vw, 44px); }
.cover { border-bottom: 2px solid var(--ink); padding-bottom: 16px; margin-bottom: 8px; display: grid; gap: 6px; }
.cover .round { font-family: var(--font-num); font-size: 13px; color: var(--pen); letter-spacing: .08em; }
.cover h1 { margin: 0; font-family: var(--font-text); font-weight: 700; font-size: clamp(22px, 3.4vw, 30px); line-height: 1.3; text-wrap: balance; }
.meta { display: flex; flex-wrap: wrap; gap: 4px 16px; font-size: 13px; color: var(--ink-soft); }
.meta b { color: var(--ink); font-weight: 600; }
.contact { margin: 4px 0 0; font-size: 13px; color: var(--pen); border: 1px solid var(--pen); background: var(--pen-soft); padding: 4px 10px; justify-self: start; }
.contact b { font-family: var(--font-num); font-weight: 500; }
.note { font-size: 12.5px; color: var(--ink-soft); margin: 0; }

.prob { padding-block: 28px; border-bottom: 1px solid var(--rule-soft); display: grid; gap: 14px; }
.prob:last-child { border-bottom: 0; }
.ph { display: flex; flex-wrap: wrap; align-items: baseline; gap: 4px 12px; }
.ph h2 { margin: 0; font-size: 18px; font-weight: 700; }
.ph .pts { font-family: var(--font-num); font-size: 13px; color: var(--ink-soft); font-variant-numeric: tabular-nums; }
.ph .area { margin-left: auto; font-size: 12px; color: var(--ink-soft); border: 1px solid var(--rule-soft); border-radius: 999px; padding: 1px 10px; }
.src { font-size: 12px; color: var(--ink-soft); margin: -8px 0 0; }
.lead p { margin: 0; }

.passage { border: 1px solid var(--rule); padding: 18px 20px; font-family: var(--font-text); font-size: 15.5px; line-height: 1.85; overflow-x: auto; }
.passage p { margin: 0 0 .25em; text-indent: 1em; word-break: keep-all; overflow-wrap: anywhere; }
.passage p.lbl, .box p.lbl { text-indent: 0; font-family: var(--font-ui); font-weight: 600; font-size: 14px; margin-top: .6em; }
.passage p.lbl:first-child { margin-top: 0; }
.passage p.attr, .stanza .attr { display: block; text-align: right; text-indent: 0; font-size: 14px; color: var(--ink-soft); margin-top: .4em; }
.passage p.omit { text-align: center; text-indent: 0; color: var(--ink-soft); }
.fns { margin-top: .8em; padding-top: .5em; border-top: 1px dashed var(--rule-soft); }
p.fn, .stanza .fn { font-family: var(--font-ui); font-size: 12.5px; line-height: 1.55; text-indent: 0 !important; color: var(--ink-soft); }
.stanza { margin-bottom: .9em; }
.stanza:last-child { margin-bottom: 0; }
.stanza span { display: block; padding-left: 1.4em; text-indent: -1.4em; }
.stanza .lbl { font-family: var(--font-ui); font-weight: 600; font-size: 14px; padding-left: 0; text-indent: 0; }
.items p { text-indent: 0; padding-left: 1.6em; text-indent: -1.6em; }

.box { position: relative; border: 1px solid var(--ink-soft); padding: 22px 18px 14px; margin-top: 6px; font-family: var(--font-text); font-size: 14.5px; line-height: 1.8; }
.bx { overflow-x: auto; }
.box > .bt { position: absolute; top: -0.8em; left: 50%; transform: translateX(-50%); background: var(--sheet); padding: 0 10px; font-family: var(--font-ui); font-weight: 600; font-size: 13px; white-space: nowrap; }
.box p { margin: 0 0 .3em; text-indent: 0; word-break: keep-all; overflow-wrap: anywhere; }
table { border-collapse: collapse; margin: 4px 0; font-family: var(--font-ui); font-size: 13.5px; }
th, td { border: 1px solid var(--rule); padding: 5px 10px; text-align: center; vertical-align: middle; }
th { background: var(--rule-soft); font-weight: 600; }

.sub { display: grid; gap: 8px; }
.sub .q { display: flex; gap: 8px; align-items: baseline; }
.sub .q .n { font-weight: 700; flex: none; }
.sub .q .t { min-width: 0; word-break: keep-all; overflow-wrap: anywhere; }
.sub .q .sp { font-family: var(--font-num); font-size: 12.5px; color: var(--ink-soft); white-space: nowrap; margin-left: 4px; }
.ans { width: 100%; min-height: 3.2em; resize: vertical; border: 0; border-bottom: 1px solid var(--rule); background:
  repeating-linear-gradient(var(--sheet) 0 1.95em, var(--rule-soft) 1.95em calc(1.95em + 1px)); color: var(--pen);
  font-family: var(--font-ui); font-size: 15px; line-height: 1.95em; padding: 0 2px; }
.ans::placeholder { color: var(--ink-soft); opacity: .6; }

.reveal { justify-self: start; border: 1px dashed var(--red); color: var(--red); background: transparent; border-radius: 6px; padding: 4px 12px; font-size: 13px; font-weight: 600; }
.key { border-left: 3px double var(--red); background: var(--red-soft); padding: 12px 16px; font-size: 14px; }
.key p { margin: 0 0 .5em; }
.key strong { color: var(--red); }
.key ul { margin: 0 0 .6em; padding-left: 1.2em; }
.key li { margin-bottom: .2em; }

.foot { max-width: 880px; margin: 18px auto 0; font-size: 12.5px; color: var(--ink-soft); display: grid; gap: 4px; }
math { font-size: 1.05em; }
math[display="block"] { margin: .4em 0; }
@media (max-width: 560px) {
  .picker { grid-template-columns: repeat(5, minmax(0, 1fr)); }
  .ph .area { margin-left: 0; }
  .passage { padding: 14px; font-size: 15px; }
}
@media (prefers-reduced-motion: reduce) { * { scroll-behavior: auto !important; } }