/* Hydrogen orbital explorer, on the site's night palette. The tokens (--dd-*)
   come from ../project.css; what the canvas draws keeps its own colours. */

:root {
    color-scheme: dark;
    --ink: var(--dd-ink);
    --muted: var(--dd-muted);
    --faint: var(--dd-faint);
    --rule: var(--dd-line);
    --panel: var(--dd-glass);
    --accent: var(--dd-amber);
    --good: #5fcf8e;
    --bad: var(--dd-danger);
    --gap: clamp(16px, 2.4vw, 28px);
    --sheet: 52%;   /* phone layout: the controls take the lower half */
}

* { box-sizing: border-box; }

/* An id selector with display:flex outranks the UA sheet's [hidden] rule, so
   #busy stayed on screen forever. Make hidden mean hidden. */
[hidden] { display: none !important; }

body {
    margin: 0;
    background: var(--dd-bg);
    color: var(--ink);
    font-family: var(--dd-sans);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    overflow: hidden;
}

button,
select,
input { font: inherit; color: inherit; }

:focus-visible {
    outline: 2px solid var(--accent);
    outline-offset: 3px;
}

/* the stage starts under the site header (64px, 56px on phones) */
#stage {
    position: fixed;
    inset: 0;
    top: var(--dd-header-h);
}

#gl {
    position: absolute;
    inset: 0;
    width: 100%;
    height: 100%;
    display: block;
    cursor: grab;
    touch-action: none;
}

#gl:active { cursor: grabbing; }

/* Vignette + a faint violet and amber haze so the void is not flat black,
   centred on the space the panel leaves, where viewer.js centres the orbital. */
#stage::after {
    content: '';
    position: absolute;
    inset: 0;
    pointer-events: none;
    --cx: calc(50% - (340px + var(--gap)) / 2);
    background:
        radial-gradient(ellipse 42% 50% at var(--cx) 44%, rgba(140, 120, 255, 0.09), transparent 70%),
        radial-gradient(ellipse 34% 34% at 12% 0%, rgba(255, 160, 80, 0.06), transparent 70%),
        radial-gradient(ellipse 72% 92% at var(--cx) 50%, transparent 45%, rgba(0, 0, 0, 0.72) 100%);
}

/* --- title -------------------------------------------------------------- */

#titlebar {
    position: absolute;
    top: clamp(22px, 3vw, 34px);
    left: clamp(20px, 3vw, 40px);
    z-index: 3;
    pointer-events: none;
}

#titlebar h1 {
    margin: 0;
    font-family: var(--dd-display);
    font-size: clamp(34px, 3.8vw, 52px);
    font-weight: 700;
    line-height: 1;
    letter-spacing: -0.035em;
    background: linear-gradient(180deg, #ffffff 10%, #cfc9e2 100%);
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
    padding-bottom: 0.06em;
    filter: drop-shadow(0 2px 18px rgba(0, 0, 0, 0.75));
}

#titlebar p {
    margin: 10px 0 0;
    font-size: 14px;
    line-height: 1.55;
    color: var(--dd-ink-2);
    max-width: 34ch;
    text-shadow: 0 2px 14px rgba(0, 0, 0, 0.9);
}

#error {
    position: absolute;
    top: 50%;
    left: 40px;
    right: calc(340px + var(--gap) + 40px);
    z-index: 6;
    padding: 16px 20px;
    background: rgba(40, 14, 14, 0.88);
    border: 1px solid rgba(255, 122, 107, 0.5);
    border-radius: 14px;
    -webkit-backdrop-filter: blur(12px);
    backdrop-filter: blur(12px);
    font-size: 14px;
}

#busy {
    position: absolute;
    bottom: 26px;
    left: clamp(20px, 3vw, 40px);
    z-index: 4;
    display: flex;
    align-items: center;
    gap: 10px;
    font-family: var(--dd-mono);
    font-size: 11.5px;
    letter-spacing: 0.14em;
    text-transform: uppercase;
    color: var(--muted);
}

.spinner {
    width: 13px;
    height: 13px;
    border: 2px solid rgba(255, 180, 106, 0.22);
    border-top-color: var(--accent);
    border-radius: 50%;
    animation: spin 0.7s linear infinite;
}

@keyframes spin { to { transform: rotate(360deg); } }

@media (prefers-reduced-motion: reduce) {
    .spinner { animation-duration: 2.4s; }
}

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

#panel {
    position: absolute;
    top: var(--gap);
    right: var(--gap);
    bottom: var(--gap);
    width: 340px;
    z-index: 5;
    overflow-y: auto;
    overscroll-behavior: contain;
    padding: 24px 22px 32px;
    background: var(--panel);
    -webkit-backdrop-filter: blur(16px) saturate(140%);
    backdrop-filter: blur(16px) saturate(140%);
    border: 1px solid var(--rule);
    border-radius: 20px;
    box-shadow: 0 30px 70px -30px rgba(0, 0, 0, 0.9);
    font-size: 13px;
    scrollbar-width: thin;
    scrollbar-color: rgba(255, 255, 255, 0.18) transparent;
}

#panel::-webkit-scrollbar { width: 8px; }
#panel::-webkit-scrollbar-thumb { background: rgba(255, 255, 255, 0.16); border-radius: 8px; }

.block { padding-bottom: 22px; margin-bottom: 22px; border-bottom: 1px solid var(--rule); }
.block:last-child { border-bottom: 0; margin-bottom: 0; padding-bottom: 0; }

.block h2 {
    margin: 0 0 14px;
    font-family: var(--dd-mono);
    font-size: 11px;
    font-weight: 500;
    letter-spacing: 0.14em;
    text-transform: uppercase;
    color: var(--muted);
}

.name {
    margin-bottom: 18px;
    font-family: var(--dd-display);
    font-size: 30px;
    font-weight: 650;
    line-height: 1.05;
    letter-spacing: -0.025em;
    color: var(--ink);
}

/* --- sliders ------------------------------------------------------------ */

.slider {
    display: grid;
    grid-template-columns: 1fr 128px 50px;
    align-items: center;
    gap: 10px;
    margin-bottom: 12px;
}

.slider > span { font-size: 13px; color: var(--dd-ink-2); }
.slider > span em {
    display: block;
    margin-top: 2px;
    font-family: var(--dd-mono);
    font-style: normal;
    font-size: 9.5px;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    color: var(--faint);
}
.slider > b {
    font-family: var(--dd-mono);
    font-size: 12px;
    font-weight: 500;
    text-align: right;
    color: var(--accent);
    white-space: nowrap;
}

input[type="range"] {
    -webkit-appearance: none;
    appearance: none;
    width: 100%;
    height: 4px;
    margin: 0;
    background: rgba(255, 255, 255, 0.14);
    border-radius: 999px;
    outline: none;
    cursor: pointer;
}

input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 14px;
    height: 14px;
    border: 0;
    border-radius: 50%;
    background: var(--accent);
    cursor: pointer;
    box-shadow: 0 0 0 4px rgba(255, 180, 106, 0.18), 0 0 12px rgba(255, 170, 90, 0.6);
}

input[type="range"]::-moz-range-thumb {
    width: 14px;
    height: 14px;
    border: 0;
    border-radius: 50%;
    background: var(--accent);
    cursor: pointer;
    box-shadow: 0 0 0 4px rgba(255, 180, 106, 0.18), 0 0 12px rgba(255, 170, 90, 0.6);
}

input[type="range"]::-moz-range-track {
    height: 4px;
    border-radius: 999px;
    background: rgba(255, 255, 255, 0.14);
}

input[type="range"]:focus-visible {
    outline: 2px solid var(--accent);
    outline-offset: 6px;
}

.field {
    display: grid;
    grid-template-columns: 1fr 180px;
    align-items: center;
    gap: 10px;
    margin-bottom: 12px;
}

.field > span { font-size: 13px; color: var(--dd-ink-2); }

select {
    width: 100%;
    min-height: 36px;
    padding: 0 30px 0 12px;
    background-color: rgba(255, 255, 255, 0.04);
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 24 24' fill='none' stroke='%23c4c2d0' stroke-width='2.4' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='m6 9 6 6 6-6'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 10px center;
    color: var(--ink);
    border: 1px solid var(--dd-line-2);
    border-radius: 10px;
    font-size: 12.5px;
    outline: none;
    cursor: pointer;
    -webkit-appearance: none;
    appearance: none;
    transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

select:hover { border-color: var(--dd-line-3); }
select:focus { border-color: var(--dd-amber-line); box-shadow: 0 0 0 4px rgba(255, 180, 106, 0.12); }

select option { background: #12141c; color: var(--ink); }
select option:disabled { color: var(--faint); }

.check {
    display: flex;
    align-items: flex-start;
    gap: 10px;
    margin-bottom: 10px;
    font-size: 12.5px;
    line-height: 1.5;
    color: var(--dd-ink-2);
    cursor: pointer;
}

.check input {
    flex: none;
    width: 15px;
    height: 15px;
    margin: 1px 0 0;
    accent-color: var(--accent);
    cursor: pointer;
}

/* --- presets ------------------------------------------------------------ */

.presets { display: flex; flex-wrap: wrap; gap: 6px; margin-top: 16px; }

.presets button {
    min-width: 40px;
    padding: 6px 12px;
    background: rgba(255, 255, 255, 0.04);
    border: 1px solid var(--dd-line-2);
    border-radius: 999px;
    color: var(--dd-ink-2);
    font-family: var(--dd-mono);
    font-size: 12px;
    cursor: pointer;
    transition: background-color 0.15s ease, border-color 0.15s ease, color 0.15s ease;
}

.presets button:hover {
    background: var(--dd-amber-soft);
    border-color: var(--dd-amber-line);
    color: var(--accent);
}

/* --- readout ------------------------------------------------------------ */

.row {
    display: grid;
    grid-template-columns: 70px 1fr;
    gap: 10px;
    padding: 8px 0;
    border-top: 1px solid var(--rule);
    align-items: baseline;
}

.row:first-of-type { border-top: 0; }
/* not uppercased: ⟨r⟩ is a radius, ⟨R⟩ would be something else */
.row > span { font-family: var(--dd-mono); font-size: 11px; letter-spacing: 0.06em; color: var(--muted); }
.row > code { font-family: var(--dd-mono); font-size: 12px; color: var(--ink); }

button.wide,
.measure-buttons button {
    min-height: 38px;
    padding: 0 16px;
    background: rgba(255, 255, 255, 0.045);
    border: 1px solid var(--dd-line-2);
    border-radius: 999px;
    color: var(--ink);
    font-size: 13px;
    font-weight: 600;
    cursor: pointer;
    transition: transform 0.2s var(--dd-ease), background-color 0.2s ease, border-color 0.2s ease,
        box-shadow 0.2s ease;
}

button.wide {
    width: 100%;
    margin-top: 14px;
}

button.wide:hover,
.measure-buttons button:hover {
    background: rgba(255, 255, 255, 0.09);
    border-color: var(--dd-line-3);
}

button.wide:active,
.measure-buttons button:active { transform: scale(0.97); }

#verifyOut { margin-top: 12px; }

.vrow {
    display: grid;
    grid-template-columns: 1fr auto auto 14px;
    gap: 8px;
    align-items: baseline;
    padding: 6px 0;
    border-top: 1px solid var(--rule);
    font-size: 11px;
}

.vrow span { color: var(--dd-ink-2); }
.vrow code { font-family: var(--dd-mono); font-size: 11px; color: var(--ink); }
.vrow em { font-style: normal; font-family: var(--dd-mono); color: var(--faint); font-size: 10px; }
.vrow b { text-align: right; }
.vrow.ok b { color: var(--good); }
.vrow.bad b { color: var(--bad); }

/* --- prose -------------------------------------------------------------- */

.hint, .caveat {
    margin: 10px 0 0;
    font-size: 12px;
    line-height: 1.6;
    color: var(--dd-ink-2);
}

.hint em { color: var(--ink); }

.caveat {
    padding-top: 14px;
    border-top: 1px solid var(--rule);
    color: var(--muted);
}

.legend { list-style: none; margin: 0; padding: 0; }
.legend li {
    position: relative;
    margin-bottom: 10px;
    padding-left: 14px;
    font-size: 12px;
    line-height: 1.6;
    color: var(--dd-ink-2);
}
.legend li::before {
    content: '';
    position: absolute;
    left: 0; top: 8px;
    width: 5px; height: 5px;
    border-radius: 50%;
    background: var(--accent);
    box-shadow: 0 0 8px rgba(255, 170, 90, 0.7);
}
.legend b { color: var(--ink); font-weight: 600; }

#superPanel { margin-top: 14px; }

/* --- measurement --------------------------------------------------------- */

.measure-buttons {
    display: grid;
    grid-template-columns: 1fr auto auto;
    gap: 6px;
    margin: 14px 0 6px;
}

.measure-buttons button { padding: 0 14px; }

/* Measure is the panel's main action */
#measureOne {
    color: var(--dd-amber-ink);
    border-color: transparent;
    background: linear-gradient(180deg, #ffcc96 0%, var(--dd-amber) 48%, #ff9a52 100%);
    box-shadow: 0 10px 26px -12px rgba(255, 150, 70, 0.65), inset 0 1px 0 rgba(255, 255, 255, 0.5);
}

#measureOne:hover {
    background: linear-gradient(180deg, #ffd4a6 0%, #ffbd7c 48%, #ffa463 100%);
    border-color: transparent;
}

#measureLast { line-height: 1.5; }

/* --- phones and narrow tablets: canvas on top, controls in a sheet below --- */

@media (max-width: 860px) {
    /* a canvas does not stretch between top and bottom, so size it outright;
       it runs 20px under the sheet's rounded corners */
    #gl { bottom: auto; height: calc(100% - var(--sheet) + 20px); }
    #stage::after { bottom: calc(var(--sheet) - 20px); --cx: 50%; }
    #panel {
        top: auto;
        left: 0;
        right: 0;
        bottom: 0;
        width: auto;
        height: var(--sheet);
        padding: 22px 20px 28px;
        border-width: 1px 0 0;
        border-radius: 20px 20px 0 0;
        box-shadow: 0 -20px 50px -30px rgba(0, 0, 0, 0.9);
    }
    #titlebar { top: 18px; }
    #titlebar h1 { font-size: 30px; }
    #titlebar p { margin-top: 6px; font-size: 13px; }
    #error { left: 20px; right: 20px; top: 20%; }
    #busy { bottom: calc(var(--sheet) + 14px); }
    .slider { grid-template-columns: 1fr minmax(110px, 46%) 52px; }
    .field { grid-template-columns: 1fr minmax(150px, 58%); }
}