/* SumIR — dark instrument-panel theme.
   Palette: warm charcoal panels, off-white text, pilot-lamp amber accent.
   Type: Chakra Petch (wordmark) / IBM Plex Sans (UI) / IBM Plex Mono (values). */

:root {
    --bg: #131417;
    --panel: #1c1e22;
    --inset: #16171a;
    --border: #2b2e35;
    --border-soft: #23262c;
    --text: #e8e5dc;
    --muted: #97938a;
    --accent: #dfa64f;
    --accent-bright: #edbd6e;
    --accent-ink: #1c1305;
    --danger: #e0685c;
    --ok: #9dbb7a;
    --radius: 12px;
    --radius-sm: 8px;
    --font-ui: "IBM Plex Sans", -apple-system, system-ui, sans-serif;
    --font-mono: "IBM Plex Mono", ui-monospace, SFMono-Regular, monospace;
    --font-display: "Chakra Petch", var(--font-ui);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: var(--font-ui);
    font-size: 15px;
    line-height: 1.55;
    color: var(--text);
    background:
        radial-gradient(1100px 500px at 50% -10%, #1a1c20 0%, var(--bg) 60%)
        var(--bg);
    min-height: 100vh;
}

.shell {
    max-width: 760px;
    margin: 0 auto;
    padding: 44px 22px 28px;
}

/* ---- header ---- */
header {
    margin-bottom: 26px;
}

.wordmark {
    font-family: var(--font-display);
    font-weight: 700;
    font-size: 2rem;
    letter-spacing: 0.06em;
    color: var(--text);
}

.wordmark::after {
    content: "";
    display: inline-block;
    width: 0.55em;
    height: 0.55em;
    margin-left: 0.45em;
    border-radius: 50%;
    background: radial-gradient(circle at 35% 30%, var(--accent-bright), var(--accent) 55%, #6e4d1d);
    box-shadow: 0 0 10px rgba(223, 166, 79, 0.55);
    vertical-align: 6%;
}

.tagline {
    color: var(--muted);
    margin-top: 4px;
}

/* ---- panels (fieldset sections) ---- */
.panel {
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 22px;
    margin-bottom: 22px;
    background: var(--panel);
}

.panel > legend {
    font-family: var(--font-mono);
    font-size: 0.72rem;
    font-weight: 500;
    letter-spacing: 0.18em;
    text-transform: uppercase;
    color: var(--muted);
    padding: 0 9px;
    margin-left: 8px;
}

/* ---- dropzone / speaker ---- */
.dropzone {
    display: flex;
    align-items: center;
    gap: 26px;
    padding: 10px 6px;
    cursor: pointer;
    border-radius: var(--radius-sm);
}

#file-input {
    display: none;
}

.speaker {
    flex: 0 0 auto;
    width: 128px;
    height: 128px;
    border-radius: 50%;
    background: var(--inset);
    border: 1px solid var(--border);
    display: grid;
    place-items: center;
    transition: border-color 0.25s ease, box-shadow 0.25s ease;
}

.speaker-cone {
    width: 96px;
    height: 96px;
    border-radius: 50%;
    background: radial-gradient(circle at 38% 32%, #26282d 0%, #1a1b1f 55%, #131417 100%);
    border: 1px solid var(--border-soft);
    display: grid;
    place-items: center;
}

.speaker-cap {
    width: 34px;
    height: 34px;
    border-radius: 50%;
    background: radial-gradient(circle at 36% 30%, #33363c, #1e2024 70%);
    border: 1px solid var(--border);
    transition: background 0.25s ease, box-shadow 0.25s ease, border-color 0.25s ease;
}

.dropzone:hover .speaker,
.dropzone.dragover .speaker {
    border-color: color-mix(in srgb, var(--accent) 55%, var(--border));
}

.dropzone.dragover .speaker {
    box-shadow: 0 0 0 4px rgba(223, 166, 79, 0.12);
}

.dropzone:hover .speaker-cap,
.dropzone.dragover .speaker-cap {
    background: radial-gradient(circle at 36% 30%, var(--accent-bright), var(--accent) 60%, #6e4d1d);
    border-color: var(--accent);
    box-shadow: 0 0 16px rgba(223, 166, 79, 0.45);
}

.dropzone-copy {
    flex: 1;
}

.drop-lead {
    font-size: 1.06rem;
    font-weight: 500;
    margin-bottom: 12px;
}

.file-types {
    margin-top: 12px;
    font-family: var(--font-mono);
    font-size: 0.78rem;
    color: var(--muted);
}

/* discreet text toggle into the single-IR bandpass flow */
.bandpass-toggle {
    display: inline-block;
    margin-top: 12px;
    padding: 0;
    background: none;
    border: none;
    font-family: var(--font-mono);
    font-size: 0.78rem;
    letter-spacing: 0.04em;
    color: var(--muted);
    cursor: pointer;
    text-decoration: underline;
    text-underline-offset: 3px;
    text-decoration-color: var(--border);
    transition: color 0.15s ease, text-decoration-color 0.15s ease;
}

.bandpass-toggle:hover {
    color: var(--accent-bright);
    text-decoration-color: var(--accent);
}

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

/* ---- buttons ---- */
.btn {
    font-family: var(--font-ui);
    font-size: 0.95rem;
    font-weight: 600;
    border-radius: var(--radius-sm);
    padding: 9px 18px;
    cursor: pointer;
    transition: background-color 0.15s ease, border-color 0.15s ease, color 0.15s ease;
}

.btn-quiet {
    background: var(--inset);
    color: var(--text);
    border: 1px solid var(--border);
}

.btn-quiet:hover {
    border-color: color-mix(in srgb, var(--accent) 45%, var(--border));
    color: var(--accent-bright);
}

.btn-primary {
    background: var(--accent);
    color: var(--accent-ink);
    border: 1px solid var(--accent);
}

.btn-primary:hover {
    background: var(--accent-bright);
    border-color: var(--accent-bright);
}

.btn:disabled {
    opacity: 0.55;
    cursor: not-allowed;
}

/* ---- voicing controls ---- */
.mode-controls-row {
    display: flex;
    align-items: center;
    gap: 10px;
}

.mode-controls {
    display: inline-flex;
    background: var(--inset);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    padding: 3px;
    gap: 2px;
}

.mode-controls label {
    cursor: pointer;
}

.mode-controls input[type="radio"] {
    position: absolute;
    opacity: 0;
    pointer-events: none;
}

.mode-controls span {
    display: inline-block;
    padding: 7px 20px;
    border-radius: 6px;
    font-size: 0.92rem;
    font-weight: 500;
    color: var(--muted);
    transition: background-color 0.15s ease, color 0.15s ease;
}

.mode-controls label:hover span {
    color: var(--text);
}

.mode-controls input:checked + span {
    background: var(--panel);
    color: var(--accent-bright);
    box-shadow: inset 0 0 0 1px var(--border);
}

.mode-controls input:focus-visible + span {
    outline: 2px solid var(--accent);
    outline-offset: 2px;
}

.mode-hint {
    margin-top: 10px;
    font-size: 0.83rem;
    color: var(--muted);
}

/* ---- advanced disclosure ---- */
.advanced {
    margin-top: 18px;
    border-top: 1px solid var(--border-soft);
    padding-top: 14px;
}

.advanced summary {
    font-family: var(--font-mono);
    font-size: 0.78rem;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    color: var(--muted);
    cursor: pointer;
    list-style: none;
    user-select: none;
}

.advanced summary::-webkit-details-marker {
    display: none;
}

.advanced summary::before {
    content: "▸";
    display: inline-block;
    margin-right: 8px;
    transition: transform 0.15s ease;
}

.advanced[open] summary::before {
    transform: rotate(90deg);
}

.advanced summary:hover {
    color: var(--text);
}

.advanced-options {
    margin-top: 16px;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 14px 18px;
}

.option-group {
    display: flex;
    flex-direction: column;
    gap: 5px;
}

.option-group label {
    font-size: 0.8rem;
    color: var(--muted);
}

/* renormalize checkbox in the bandpass flow (#9) */
.bp-normalize-row {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-top: 16px;
}

.checkbox-label {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    font-size: 0.8rem;
    color: var(--muted);
    cursor: pointer;
}

.checkbox-label input[type="checkbox"] {
    width: 15px;
    height: 15px;
    accent-color: var(--accent);
    cursor: pointer;
}

/* ---- fields ---- */
select,
input[type="number"] {
    font-family: var(--font-ui);
    font-size: 0.92rem;
    color: var(--text);
    background: var(--inset);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    padding: 8px 10px;
    appearance: none;
}

select {
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='10' height='6'%3E%3Cpath d='M1 1l4 4 4-4' stroke='%2397938a' fill='none' stroke-width='1.5'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 10px center;
    padding-right: 28px;
}

select:hover,
input[type="number"]:hover {
    border-color: color-mix(in srgb, var(--accent) 35%, var(--border));
}

select:focus-visible,
input[type="number"]:focus-visible,
.btn:focus-visible,
.advanced summary:focus-visible,
.dropzone:focus-visible {
    outline: 2px solid var(--accent);
    outline-offset: 2px;
}

input[type="number"]::placeholder {
    color: color-mix(in srgb, var(--muted) 70%, transparent);
}

/* ---- notices ---- */
.notice {
    border-radius: var(--radius);
    padding: 18px 22px;
    margin-bottom: 22px;
    background: var(--panel);
    border: 1px solid var(--border);
}

.processing {
    display: flex;
    align-items: center;
    gap: 14px;
    color: var(--muted);
}

.spinner {
    width: 18px;
    height: 18px;
    border-radius: 50%;
    border: 2px solid var(--border);
    border-top-color: var(--accent);
    animation: spin 0.9s linear infinite;
}

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

.error {
    border-color: color-mix(in srgb, var(--danger) 55%, var(--border));
}

.error p {
    color: var(--danger);
}

.single-candidate {
    border-color: color-mix(in srgb, var(--accent) 45%, var(--border));
}

.single-candidate p + p {
    margin-top: 6px;
    color: var(--muted);
}

.single-candidate .mono {
    color: var(--accent-bright);
}

.mono {
    font-family: var(--font-mono);
    font-size: 0.88rem;
}

/* ---- output ---- */
.plot-container {
    margin-bottom: 16px;
}

#plot-canvas {
    display: block;
    width: 100%;
    height: 420px;
    border: 1px solid var(--border-soft);
    border-radius: var(--radius-sm);
    background-color: var(--inset);
}

.output-row {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

#output-filename {
    color: var(--accent-bright);
    overflow-wrap: anywhere;
}

.output-format {
    display: flex;
    align-items: center;
    justify-content: flex-end;
    gap: 10px;
    flex-wrap: wrap;
}

/* ---- info tooltip (circle-i) ---- */
.info-tooltip {
    position: relative;
    display: inline-flex;
}

.info-trigger {
    width: 20px;
    height: 20px;
    padding: 0;
    border-radius: 50%;
    border: 1px solid var(--border);
    background: var(--inset);
    color: var(--muted);
    font-family: var(--font-mono);
    font-style: italic;
    font-weight: 600;
    font-size: 0.72rem;
    line-height: 1;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: color 0.15s ease, border-color 0.15s ease;
}

.info-trigger:hover,
.info-trigger[aria-expanded="true"] {
    color: var(--accent-bright);
    border-color: color-mix(in srgb, var(--accent) 45%, var(--border));
}

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

.info-popover {
    position: absolute;
    top: calc(100% + 8px);
    left: 0;
    z-index: 30;
    width: max-content;
    max-width: min(300px, calc(100vw - 44px));
    background: var(--panel);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    padding: 12px 14px;
    font-size: 0.83rem;
    line-height: 1.5;
    color: var(--text);
    box-shadow: 0 12px 30px rgba(0, 0, 0, 0.45);
}

.info-popover:focus {
    outline: none;
}

.info-popover p + p {
    margin-top: 8px;
}

.info-popover strong {
    color: var(--accent-bright);
    font-weight: 600;
}

.info-popover a {
    color: var(--accent);
}

/* ---- modal ---- */
.modal-backdrop {
    position: fixed;
    inset: 0;
    background: rgba(10, 10, 12, 0.68);
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 24px;
    z-index: 50;
}

.modal-dialog {
    position: relative;
    background: var(--panel);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    width: 100%;
    max-width: 560px;
    max-height: calc(100vh - 48px);
    overflow-y: auto;
    padding: 30px 26px 24px;
    box-shadow: 0 24px 60px rgba(0, 0, 0, 0.5);
}

.modal-dialog:focus {
    outline: none;
}

.modal-close {
    position: absolute;
    top: 12px;
    right: 12px;
    width: 30px;
    height: 30px;
    border-radius: 50%;
    border: 1px solid var(--border);
    background: var(--inset);
    color: var(--muted);
    font-size: 1.1rem;
    line-height: 1;
    cursor: pointer;
    transition: color 0.15s ease, border-color 0.15s ease;
}

.modal-close:hover {
    color: var(--accent-bright);
    border-color: color-mix(in srgb, var(--accent) 45%, var(--border));
}

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

.modal-body p {
    margin-bottom: 14px;
    font-size: 0.92rem;
    line-height: 1.6;
    color: var(--text);
}

.modal-body p:last-child {
    margin-bottom: 0;
}

.modal-body strong {
    color: var(--accent-bright);
    font-weight: 600;
}

.modal-body a {
    color: var(--accent);
}

.popover-list {
    margin: 4px 0 14px;
    padding-left: 20px;
}

.popover-list li {
    margin-bottom: 10px;
}

.popover-list li:last-child {
    margin-bottom: 0;
}

body.modal-open {
    overflow: hidden;
}

/* ---- footer ---- */
footer {
    text-align: center;
    padding-top: 6px;
}

footer p {
    font-family: var(--font-mono);
    font-size: 0.75rem;
    color: var(--muted);
}

.link-btn {
    background: none;
    border: none;
    padding: 0;
    font: inherit;
    color: var(--accent);
    text-decoration: underline;
    cursor: pointer;
}

.link-btn:hover {
    color: var(--accent-bright);
}

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

/* ---- utility ---- */
.hidden {
    display: none !important;
}

/* ---- responsive ---- */
@media (max-width: 560px) {
    .shell {
        padding: 28px 14px 20px;
    }

    .dropzone {
        flex-direction: column;
        text-align: center;
        gap: 18px;
    }

    .mode-controls-row {
        gap: 8px;
    }

    .mode-controls {
        display: flex;
        flex: 1 1 auto;
        min-width: 0;
    }

    .mode-controls label {
        flex: 1;
    }

    .mode-controls span {
        display: block;
        text-align: center;
        padding: 7px 0;
    }

    .info-popover {
        left: auto;
        right: 0;
        max-width: calc(100vw - 28px);
    }

    .modal-dialog {
        padding: 26px 18px 20px;
    }

    #plot-canvas {
        height: 300px;
    }

    .output-row,
    .output-format {
        flex-direction: column;
        align-items: stretch;
    }

    .output-format .btn {
        width: 100%;
    }
}

/* ---- reduced motion ---- */
@media (prefers-reduced-motion: reduce) {
    * {
        transition: none !important;
        animation-duration: 1.5s !important;
    }
}