/* ==========================================================
C Visual Lab — components (cards, buttons, tabs, viz, quiz)
========================================================== */

/* ---------- buttons ---------- */
.btn {
display: inline-flex; align-items: center; justify-content: center; gap: 8px;
min-height: 44px; padding: 9px 18px;
font: 600 0.9rem var(--sans); color: var(--text);
background: var(--raised);
border: 1px solid var(--border-strong);
border-radius: var(--radius-sm);
cursor: pointer;
transition: background 0.15s ease, border-color 0.15s ease, transform 0.1s ease;
text-decoration: none;
}
.btn:hover { background: color-mix(in srgb, var(--raised) 70%, var(--surface)); border-color: var(--cyan); text-decoration: none; }
.btn:active { transform: translateY(1px); }
.btn-primary { background: linear-gradient(135deg, #14b3c7, #0e93a5); border-color: transparent; color: #04222a; }
.btn-primary:hover { background: linear-gradient(135deg, #2cc9dd, #14a5b8); border-color: transparent; }
.btn-purple { background: var(--purple-soft); border-color: var(--purple); color: var(--purple); }
.btn-danger { background: var(--red-soft); border-color: var(--red); color: var(--red); }
.btn-ghost { background: transparent; }
.btn-sm { min-height: 34px; padding: 5px 12px; font-size: 0.82rem; }
.btn[disabled] { opacity: 0.45; cursor: not-allowed; }
.btn-row { display: flex; flex-wrap: wrap; gap: 10px; margin: 12px 0; }

/* icon-only button (theme toggle) */
.icon-btn {
width: 38px; height: 38px; border-radius: 9px;
display: grid; place-items: center;
background: var(--raised); border: 1px solid var(--border);
color: var(--muted); cursor: pointer; font-size: 1rem;
}
.icon-btn:hover { color: var(--text); border-color: var(--border-strong); }

/* ---------- cards & grids ---------- */
.card {
background: var(--surface);
border: 1px solid var(--border);
border-radius: var(--radius);
padding: 18px 20px;
}
.card.tight { padding: 14px 16px; }
.grid { display: grid; gap: 16px; }
.grid.cols-2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid.cols-3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.grid.cols-4 { grid-template-columns: repeat(4, minmax(0, 1fr)); }
@media (max-width: 860px) {
.grid.cols-3, .grid.cols-4 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}
@media (max-width: 600px) {
.grid.cols-2, .grid.cols-3, .grid.cols-4 { grid-template-columns: minmax(0, 1fr); }
}

/* ---------- badges & pills ---------- */
.pill {
display: inline-flex; align-items: center; gap: 6px;
font: 600 0.74rem var(--mono);
padding: 3px 10px; border-radius: 999px;
border: 1px solid var(--border);
color: var(--muted); white-space: nowrap;
}
.pill.cyan { color: var(--cyan); background: var(--cyan-soft); border-color: color-mix(in srgb, var(--cyan) 45%, transparent); }
.pill.purple { color: var(--purple); background: var(--purple-soft); border-color: color-mix(in srgb, var(--purple) 45%, transparent); }
.pill.orange { color: var(--orange); background: var(--orange-soft); border-color: color-mix(in srgb, var(--orange) 45%, transparent); }
.pill.red { color: var(--red); background: var(--red-soft); border-color: color-mix(in srgb, var(--red) 45%, transparent); }
.pill.green { color: var(--green); background: var(--green-soft); border-color: color-mix(in srgb, var(--green) 45%, transparent); }

/* ---------- callouts ---------- */
.callout {
display: flex; gap: 12px; align-items: flex-start;
border: 1px solid var(--border);
border-left: 3px solid var(--cyan);
border-radius: var(--radius-sm);
background: var(--surface);
padding: 13px 16px; margin: 14px 0;
font-size: 0.94rem;
}
.callout .co-icon { flex: none; font-size: 1.05rem; line-height: 1.4; }
.callout p { margin: 0; }
.callout.warn { border-left-color: var(--orange); background: color-mix(in srgb, var(--orange-soft) 55%, var(--surface)); }
.callout.danger { border-left-color: var(--red); background: color-mix(in srgb, var(--red-soft) 55%, var(--surface)); }
.callout.good { border-left-color: var(--green); background: color-mix(in srgb, var(--green-soft) 55%, var(--surface)); }
.callout.idea { border-left-color: var(--purple); background: color-mix(in srgb, var(--purple-soft) 55%, var(--surface)); }

/* ---------- tooltips ---------- */
.term {
border-bottom: 1px dashed var(--purple);
cursor: help; position: relative; color: var(--text);
}
.term::after {
content: attr(data-tip);
position: absolute; left: 50%; bottom: calc(100% + 8px);
transform: translateX(-50%) translateY(4px);
width: max-content; max-width: 260px;
background: var(--raised); color: var(--text);
border: 1px solid var(--border-strong);
border-radius: 8px; padding: 8px 11px;
font-size: 0.78rem; line-height: 1.45; font-family: var(--sans); font-weight: 400;
box-shadow: var(--shadow);
opacity: 0; pointer-events: none;
transition: opacity 0.15s ease, transform 0.15s ease;
z-index: 60; white-space: normal;
}
.term:hover::after, .term:focus-visible::after {
opacity: 1; transform: translateX(-50%) translateY(0);
}

/* ---------- tabs ---------- */
.tabs { margin: 16px 0; }
.tab-list {
display: flex; flex-wrap: wrap; gap: 6px;
border-bottom: 1px solid var(--border);
padding-bottom: 0; margin-bottom: 18px;
}
.tab-btn {
font: 600 0.88rem var(--sans); color: var(--muted);
background: none; border: none; border-bottom: 2px solid transparent;
padding: 10px 14px; cursor: pointer; border-radius: 8px 8px 0 0;
min-height: 44px;
}
.tab-btn:hover { color: var(--text); background: var(--raised); }
.tab-btn[aria-selected="true"] { color: var(--cyan); border-bottom-color: var(--cyan); }
.tab-panel[hidden] { display: none; }

/* file tabs (encapsulation demo) */
.file-tabs .tab-btn { font-family: var(--mono); font-size: 0.8rem; }

/* ---------- dashboard widgets ---------- */
.stat-card { text-align: left; }
.stat-card .stat-label { font: 600 0.72rem var(--mono); letter-spacing: 0.08em; text-transform: uppercase; color: var(--faint); }
.stat-card .stat-value { font: 700 1.9rem var(--mono); margin: 4px 0 2px; color: var(--cyan); }
.stat-card .stat-sub { font-size: 0.8rem; color: var(--muted); }

/* ---------- roadmap ---------- */
.roadmap { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 12px; counter-reset: stage; }
@media (max-width: 700px) { .roadmap { grid-template-columns: minmax(0, 1fr); } }
.roadmap-card {
display: flex; gap: 13px; align-items: flex-start;
background: var(--surface); border: 1px solid var(--border);
border-radius: var(--radius); padding: 14px 16px;
color: var(--text);
}
.roadmap-card:hover { text-decoration: none; border-color: var(--cyan); }
.roadmap-card .stage-num {
flex: none; width: 32px; height: 32px; border-radius: 9px;
display: grid; place-items: center;
font: 700 0.85rem var(--mono);
background: var(--cyan-soft); color: var(--cyan);
border: 1px solid color-mix(in srgb, var(--cyan) 40%, transparent);
}
.roadmap-card.done .stage-num { background: var(--green-soft); color: var(--green); border-color: var(--green); }
.roadmap-card h3 { margin: 0 0 3px; font-size: 0.96rem; }
.roadmap-card p { margin: 0; font-size: 0.82rem; color: var(--muted); }
.roadmap-card .done-check { margin-left: auto; color: var(--green); font-weight: 700; }

/* ---------- comparison panel (C vs C++) ---------- */
.compare { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; }
@media (max-width: 700px) { .compare { grid-template-columns: 1fr; } }
.compare .card h3 { display: flex; align-items: center; gap: 8px; }

/* ---------- simulator shells ---------- */
.sim {
border: 1px solid var(--border-strong);
border-radius: var(--radius);
background: var(--surface);
margin: 18px 0;
overflow: hidden;
}
.sim-head {
display: flex; align-items: center; gap: 10px; flex-wrap: wrap;
padding: 11px 16px;
background: var(--raised);
border-bottom: 1px solid var(--border);
}
.sim-head h3 { margin: 0; font-size: 0.95rem; display: flex; align-items: center; gap: 8px; }
.sim-head .spacer { flex: 1; }
.sim-body { padding: 16px; }
.sim-cols { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
@media (max-width: 820px) { .sim-cols { grid-template-columns: 1fr; } }

/* controls inside sims */
.field-row { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; margin: 8px 0; }
.field-row label { font-size: 0.85rem; color: var(--muted); min-width: 110px; }
select, input[type="text"], input[type="number"], textarea {
font: 400 0.88rem var(--mono);
color: var(--text); background: var(--inset);
border: 1px solid var(--border-strong);
border-radius: 8px; padding: 8px 10px;
min-height: 40px;
}
textarea { width: 100%; resize: vertical; line-height: 1.55; }
select:focus, input:focus, textarea:focus { outline: 2px solid var(--cyan); outline-offset: 1px; }
input[type="checkbox"] { width: 18px; height: 18px; accent-color: var(--cyan); }
input[type="range"] { accent-color: var(--cyan); }

/* console output */
.console {
background: var(--code-bg); color: #cfe3d8;
font: 0.82rem/1.65 var(--mono);
border: 1px solid var(--code-border); border-radius: var(--radius-sm);
padding: 12px 14px; min-height: 72px;
white-space: pre-wrap; word-break: break-word;
}
.console .c-ok { color: var(--green); }
.console .c-err { color: var(--red); }
.console .c-warn { color: var(--orange); }
.console .c-dim { color: #6b7a96; }
.console .c-cyan { color: var(--cyan); }

/* ---------- memory visualization ---------- */
.mem-grid { display: flex; flex-wrap: wrap; gap: 4px; margin: 10px 0; }
.mem-byte {
width: 46px; height: 52px; border-radius: 7px;
border: 1px solid var(--border-strong);
background: var(--inset);
display: flex; flex-direction: column; align-items: center; justify-content: center; gap: 1px;
font-family: var(--mono); position: relative;
}
.mem-byte .addr { font-size: 0.56rem; color: var(--faint); }
.mem-byte .val { font-size: 0.72rem; font-weight: 700; color: var(--text); }
.mem-byte.f-cyan { background: var(--cyan-soft); border-color: var(--cyan); }
.mem-byte.f-purple { background: var(--purple-soft); border-color: var(--purple); }
.mem-byte.f-green { background: var(--green-soft); border-color: var(--green); }
.mem-byte.f-orange { background: var(--orange-soft); border-color: var(--orange); }
.mem-byte.f-red { background: var(--red-soft); border-color: var(--red); }
.mem-byte.pad {
background: repeating-linear-gradient(45deg, transparent 0 4px, rgba(148,163,184,0.10) 4px 8px);
border-style: dashed;
}
.mem-byte.pad .val { color: var(--faint); font-weight: 400; }
.mem-legend { display: flex; flex-wrap: wrap; gap: 8px 14px; font-size: 0.78rem; color: var(--muted); margin-top: 8px; }
.mem-legend .key { display: inline-flex; align-items: center; gap: 6px; }
.mem-legend .swatch { width: 12px; height: 12px; border-radius: 3px; border: 1px solid var(--border-strong); display: inline-block; }

/* field/offset table */
table.data {
width: 100%; border-collapse: collapse;
font-size: 0.84rem; margin: 12px 0;
}
table.data th, table.data td {
text-align: left; padding: 8px 10px;
border-bottom: 1px solid var(--border);
}
table.data th { font: 600 0.72rem var(--mono); text-transform: uppercase; letter-spacing: 0.07em; color: var(--faint); }
table.data td.mono, table.data .mono { font-family: var(--mono); font-size: 0.8rem; }
table.data tr.pad-row td { color: var(--faint); font-style: italic; }

/* object/record box */
.obj-box {
border: 1.5px solid var(--cyan); border-radius: var(--radius);
background: var(--cyan-soft); padding: 12px 14px;
font-family: var(--mono); font-size: 0.84rem;
min-width: 200px;
}
.obj-box .obj-title { font-weight: 700; color: var(--cyan); margin-bottom: 8px; font-size: 0.8rem; }
.obj-box .obj-field {
display: flex; justify-content: space-between; gap: 14px;
background: var(--surface); border: 1px solid var(--border);
border-radius: 6px; padding: 5px 10px; margin: 4px 0;
}
.obj-box .obj-field .fname { color: var(--muted); }
.obj-box .obj-field .fval { color: var(--green); font-weight: 600; }
.obj-box.nested-base { border-color: var(--purple); background: var(--purple-soft); }
.obj-box.nested-base > .obj-title { color: var(--purple); }

/* loose variables (concepts page) */
.loose-vars { display: flex; flex-wrap: wrap; gap: 7px; align-content: flex-start; min-height: 90px; }
.loose-var {
font: 0.74rem var(--mono); color: var(--orange);
background: var(--orange-soft);
border: 1px dashed color-mix(in srgb, var(--orange) 50%, transparent);
border-radius: 6px; padding: 4px 9px;
}

/* ---------- state machine ---------- */
.sm-wrap { display: flex; flex-wrap: wrap; gap: 12px; align-items: center; justify-content: center; margin: 12px 0; }
.sm-node {
min-width: 118px; text-align: center;
border: 1.5px solid var(--border-strong); border-radius: 10px;
background: var(--inset); padding: 10px 12px;
font-family: var(--mono); font-size: 0.78rem; color: var(--muted);
transition: border-color 0.25s ease, background 0.25s ease, color 0.25s ease;
}
.sm-node .sm-val { display: block; font-size: 0.66rem; color: var(--faint); margin-top: 3px; }
.sm-node.active { border-color: var(--cyan); background: var(--cyan-soft); color: var(--cyan); }
.sm-node.active.err { border-color: var(--red); background: var(--red-soft); color: var(--red); }
.sm-arrow { color: var(--faint); font-size: 1.1rem; user-select: none; }

/* ---------- quiz ---------- */
.quiz-box {
border: 1px solid color-mix(in srgb, var(--purple) 40%, transparent);
border-radius: var(--radius);
background: color-mix(in srgb, var(--purple-soft) 45%, var(--surface));
padding: 16px 18px; margin: 18px 0;
}
.quiz-box .quiz-tag { font: 700 0.7rem var(--mono); letter-spacing: 0.1em; text-transform: uppercase; color: var(--purple); }
.quiz-box .quiz-q { font-weight: 600; margin: 8px 0 12px; }
.quiz-opts { display: grid; gap: 8px; }
.quiz-opt {
text-align: left; font: 0.88rem var(--sans); color: var(--text);
background: var(--surface); border: 1px solid var(--border-strong);
border-radius: 8px; padding: 10px 13px; cursor: pointer;
min-height: 44px; width: 100%;
transition: border-color 0.15s ease, background 0.15s ease;
}
.quiz-opt:hover { border-color: var(--purple); }
.quiz-opt.correct { border-color: var(--green); background: var(--green-soft); color: var(--green); font-weight: 600; }
.quiz-opt.wrong { border-color: var(--red); background: var(--red-soft); color: var(--red); }
.quiz-opt[disabled] { cursor: default; }
.quiz-explain {
margin-top: 12px; font-size: 0.86rem; color: var(--muted);
border-top: 1px dashed var(--border-strong); padding-top: 10px;
}
.quiz-explain.ok { color: var(--green); }
.quiz-explain .exp-body { color: var(--muted); font-weight: 400; }

/* ---------- warning cards (pitfalls) ---------- */
.warn-card {
border: 1px solid var(--border);
border-left: 4px solid var(--orange);
border-radius: var(--radius);
background: var(--surface);
margin: 14px 0; overflow: hidden;
}
.warn-card[data-sev="red"] { border-left-color: var(--red); }
.warn-card[data-sev="orange"] { border-left-color: var(--orange); }
.warn-card[data-sev="yellow"] { border-left-color: #e7c94c; }
.warn-card[data-sev="green"] { border-left-color: var(--green); }
.warn-card > summary {
list-style: none; cursor: pointer;
display: flex; align-items: center; gap: 11px;
padding: 13px 16px; font-weight: 600; font-size: 0.94rem;
}
.warn-card > summary::-webkit-details-marker { display: none; }
.warn-card > summary:hover { background: var(--raised); }
.warn-card > summary .chev { margin-left: auto; color: var(--faint); transition: transform 0.2s ease; flex: none; }
.warn-card[open] > summary .chev { transform: rotate(90deg); }
.warn-card .warn-body { padding: 4px 18px 18px; border-top: 1px solid var(--border); }
.warn-card .warn-sec { margin: 12px 0; }
.warn-card .warn-sec h4 {
font: 700 0.72rem var(--mono); letter-spacing: 0.08em;
text-transform: uppercase; color: var(--faint); margin: 0 0 5px;
}
.rule-line {
font-weight: 600; font-size: 0.92rem;
border: 1px dashed var(--border-strong); border-radius: 8px;
background: var(--raised); padding: 10px 14px; margin-top: 14px;
}
.rule-line .rl-tag { color: var(--purple); font: 700 0.72rem var(--mono); text-transform: uppercase; letter-spacing: 0.08em; margin-right: 8px; }

/* severity meter */
.sev-meter { display: flex; align-items: center; gap: 6px; margin: 8px 0 2px; flex-wrap: wrap; }
.sev-seg { width: 34px; height: 10px; border-radius: 4px; background: var(--inset); border: 1px solid var(--border); }
.sev-seg.on-green { background: var(--green); border-color: var(--green); }
.sev-seg.on-yellow { background: #e7c94c; border-color: #e7c94c; }
.sev-seg.on-orange { background: var(--orange); border-color: var(--orange); }
.sev-seg.on-red { background: var(--red); border-color: var(--red); }
.sev-label { font: 600 0.74rem var(--mono); color: var(--muted); margin-left: 4px; }

/* ---------- file visibility (encapsulation) ---------- */
.private-field { position: relative; transition: filter 0.3s ease, opacity 0.3s ease; }
.locked .private-field { filter: blur(4px); opacity: 0.55; user-select: none; }
.lock-note {
display: none; font: 600 0.78rem var(--mono); color: var(--purple);
background: var(--purple-soft); border: 1px solid color-mix(in srgb, var(--purple) 40%, transparent);
border-radius: 7px; padding: 6px 11px; margin-top: 8px;
}
.locked .lock-note { display: inline-block; }

/* ---------- steps / traces ---------- */
.trace { list-style: none; counter-reset: step; margin: 12px 0; padding: 0; }
.trace li {
counter-increment: step;
display: flex; gap: 12px; align-items: flex-start;
padding: 9px 0; border-bottom: 1px dashed var(--border);
font-size: 0.9rem;
}
.trace li::before {
content: counter(step);
flex: none; width: 24px; height: 24px; border-radius: 50%;
display: grid; place-items: center;
font: 700 0.72rem var(--mono);
background: var(--purple-soft); color: var(--purple);
border: 1px solid color-mix(in srgb, var(--purple) 40%, transparent);
}

/* verdict banners */
.verdict {
border-radius: var(--radius-sm); padding: 11px 15px; margin: 12px 0;
font-size: 0.9rem; border: 1px solid var(--border);
display: flex; gap: 10px; align-items: flex-start;
}
.verdict.v-ok { border-color: var(--green); background: var(--green-soft); }
.verdict.v-warn { border-color: var(--orange); background: var(--orange-soft); }
.verdict.v-err { border-color: var(--red); background: var(--red-soft); }
.verdict.v-info { border-color: var(--cyan); background: var(--cyan-soft); }
.verdict b { display: block; margin-bottom: 2px; }

/* hero */
.hero {
text-align: left; padding: 40px 0 8px;
}
.hero h1 {
font-size: clamp(1.8rem, 4.5vw, 2.7rem);
background: linear-gradient(100deg, var(--cyan), var(--purple));
-webkit-background-clip: text; background-clip: text;
-webkit-text-fill-color: transparent; color: transparent;
max-width: 720px;
}
.hero .lede { font-size: 1.06rem; color: var(--muted); max-width: 680px; }

/* svg diagrams */
.diagram-svg { width: 100%; height: auto; display: block; margin: 10px 0; }
.diagram-svg text { font-family: var(--mono); }

/* mark complete strip */
.complete-strip {
display: flex; align-items: center; gap: 14px; flex-wrap: wrap;
border: 1px solid var(--border); border-radius: var(--radius);
background: var(--surface); padding: 15px 18px; margin: 36px 0 8px;
}
.complete-strip .cs-msg { font-size: 0.92rem; color: var(--muted); flex: 1; min-width: 200px; }