/* =========================================================
   Ultrasonic — Data over Sound
   ========================================================= */

:root {
    --bg:        #0b1020;
    --bg-soft:   #131a30;
    --bg-elev:   #1a2342;
    --border:    #2a3354;
    --text:      #e6ebff;
    --text-dim:  #9aa3c7;
    --accent:    #38e8ff;
    --accent-2:  #ff5ec7;
    --good:      #4ade80;
    --warn:      #fbbf24;
    --bad:       #f87171;
    --radius:    12px;
    --mono:      ui-monospace, "JetBrains Mono", "SF Mono", Consolas, monospace;
    --sans:      -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, system-ui, sans-serif;
}

* { box-sizing: border-box; }

html, body {
    margin: 0; padding: 0;
    background:
        radial-gradient(ellipse at top, rgba(56,232,255,0.08), transparent 60%),
        radial-gradient(ellipse at bottom right, rgba(255,94,199,0.06), transparent 60%),
        var(--bg);
    color: var(--text);
    font-family: var(--sans);
    line-height: 1.55;
    min-height: 100vh;
}

/* ---- Top Bar ---- */
.top-bar {
    display: flex; align-items: center; justify-content: space-between;
    padding: 16px 24px;
    background: rgba(11,16,32,0.85);
    backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border);
    position: sticky; top: 0; z-index: 100;
}
.brand {
    font-family: var(--mono);
    font-weight: 700; font-size: 18px;
    color: var(--accent);
    text-decoration: none;
    letter-spacing: -0.5px;
}
.brand::before { content: "~ "; opacity: 0.6; }
.top-bar nav { display: flex; gap: 24px; }
.top-bar nav a {
    color: var(--text-dim);
    text-decoration: none;
    font-size: 14px;
    padding: 4px 8px;
    border-radius: 6px;
    transition: color .15s, background .15s;
}
.top-bar nav a:hover { color: var(--text); }
.top-bar nav a.active { color: var(--accent); background: rgba(56,232,255,0.1); }

/* ---- Container ---- */
.container {
    max-width: 960px;
    margin: 0 auto;
    padding: 32px 24px 64px;
}

h1 {
    font-size: 32px;
    margin: 8px 0 16px;
    background: linear-gradient(135deg, var(--accent), var(--accent-2));
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
}
h2 { font-size: 22px; margin: 32px 0 12px; color: var(--text); }
h3 { font-size: 17px; margin: 20px 0 8px; color: var(--accent); }

.lead {
    font-size: 17px;
    color: var(--text-dim);
    margin-bottom: 24px;
}

/* ---- Research Page ---- */
.page-research section {
    background: var(--bg-soft);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 20px 24px;
    margin-bottom: 16px;
}
.page-research ul, .page-research ol { padding-left: 20px; }
.page-research li { margin: 6px 0; color: var(--text-dim); }
.page-research li strong { color: var(--text); }
.page-research p { color: var(--text-dim); }
.page-research p strong, .page-research p em { color: var(--text); }
.page-research em { color: #c2cae8; font-style: italic; }

.data-table {
    width: 100%;
    border-collapse: collapse;
    margin: 12px 0;
    background: var(--bg-elev);
    border-radius: 8px;
    overflow: hidden;
    font-family: var(--mono);
    font-size: 14px;
}
.data-table th, .data-table td {
    padding: 8px 12px;
    text-align: left;
    border-bottom: 1px solid var(--border);
}
.data-table th { background: rgba(56,232,255,0.08); color: var(--accent); }
.data-table tbody tr:last-child td { border-bottom: none; }
.data-table tbody tr:hover { background: rgba(56,232,255,0.04); }

.frame-diagram {
    background: var(--bg-elev);
    color: var(--accent);
    border: 1px solid var(--border);
    padding: 16px;
    border-radius: 8px;
    overflow-x: auto;
    font-family: var(--mono);
    font-size: 12px;
    line-height: 1.4;
}

.info-box {
    background: rgba(56,232,255,0.06);
    border-left: 3px solid var(--accent);
    padding: 12px 16px;
    border-radius: 6px;
    color: var(--text-dim);
    margin: 12px 0;
}

.examples { display: grid; gap: 12px; }
.examples dt {
    font-weight: 600;
    color: var(--accent);
    font-family: var(--mono);
    font-size: 14px;
}
.examples dd {
    margin: 0 0 8px;
    padding-left: 12px;
    border-left: 2px solid var(--border);
    color: var(--text-dim);
    font-size: 14px;
}

.links li { font-size: 14px; }
.cta { text-align: center; margin: 32px 0 0; }

/* ---- Use case grid ---- */
.usecase-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: 12px;
    margin-top: 12px;
}
.usecase {
    background: var(--bg-elev);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 14px 16px;
}
.usecase h3 { margin: 0 0 6px; font-size: 15px; color: var(--text); }
.usecase p { margin: 0; font-size: 13px; color: var(--text-dim); }

/* ---- Buttons ---- */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 10px 20px;
    background: linear-gradient(135deg, var(--accent), #1ec5dd);
    color: #001425;
    border: none;
    border-radius: 8px;
    font-weight: 600;
    font-size: 15px;
    cursor: pointer;
    text-decoration: none;
    transition: transform .1s, box-shadow .15s, opacity .15s;
    box-shadow: 0 4px 20px rgba(56,232,255,0.2);
}
.btn:hover { transform: translateY(-1px); box-shadow: 0 6px 24px rgba(56,232,255,0.35); }
.btn:active { transform: translateY(0); }
.btn:disabled { opacity: 0.5; cursor: not-allowed; transform: none; }
.btn.secondary {
    background: var(--bg-elev);
    color: var(--text);
    border: 1px solid var(--border);
    box-shadow: none;
}
.btn.secondary:hover { background: var(--border); box-shadow: none; }
.btn.danger {
    background: linear-gradient(135deg, var(--bad), #c64242);
    color: white;
    box-shadow: 0 4px 20px rgba(248,113,113,0.25);
}
.btn.large { padding: 14px 28px; font-size: 16px; }

/* ---- Bottom bar ---- */
.bottom-bar {
    border-top: 1px solid var(--border);
    padding: 16px 24px;
    text-align: center;
    color: var(--text-dim);
    font-size: 12px;
    font-family: var(--mono);
}

/* =========================================================
   APP (index.html)
   ========================================================= */

.tab-bar {
    display: flex;
    background: var(--bg-soft);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 4px;
    margin-bottom: 20px;
    gap: 4px;
}
.tab-bar button {
    flex: 1;
    background: transparent;
    border: none;
    color: var(--text-dim);
    padding: 10px 16px;
    font-size: 15px;
    font-weight: 600;
    font-family: var(--sans);
    cursor: pointer;
    border-radius: 8px;
    transition: background .15s, color .15s;
}
.tab-bar button:hover { color: var(--text); }
.tab-bar button.active {
    background: linear-gradient(135deg, var(--accent), #1ec5dd);
    color: #001425;
}

.tab-panel { display: none; }
.tab-panel.active { display: block; }

.card {
    background: var(--bg-soft);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 20px;
    margin-bottom: 16px;
}
.card h2 { margin-top: 0; font-size: 18px; }

.input-group { margin-bottom: 14px; }
.input-group label {
    display: block;
    margin-bottom: 6px;
    font-size: 13px;
    color: var(--text-dim);
    font-weight: 500;
}
.input-group input[type="text"],
.input-group input[type="file"],
.input-group select,
.input-group textarea {
    width: 100%;
    background: var(--bg-elev);
    color: var(--text);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 10px 12px;
    font-size: 14px;
    font-family: var(--sans);
    transition: border-color .15s;
}
.input-group input:focus, .input-group select:focus, .input-group textarea:focus {
    outline: none;
    border-color: var(--accent);
}
.input-group textarea { min-height: 90px; resize: vertical; font-family: var(--mono); }

.mode-tabs {
    display: flex;
    gap: 8px;
    margin-bottom: 16px;
}
.mode-tabs button {
    background: var(--bg-elev);
    color: var(--text-dim);
    border: 1px solid var(--border);
    padding: 8px 14px;
    border-radius: 8px;
    font-size: 13px;
    font-weight: 500;
    cursor: pointer;
    transition: all .15s;
}
.mode-tabs button:hover { color: var(--text); }
.mode-tabs button.active {
    color: var(--accent);
    border-color: var(--accent);
    background: rgba(56,232,255,0.08);
}

.button-row {
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
    margin-top: 4px;
}

/* ---- Status / Log ---- */
.status {
    font-family: var(--mono);
    font-size: 13px;
    padding: 10px 14px;
    border-radius: 8px;
    background: var(--bg-elev);
    border: 1px solid var(--border);
    margin-top: 12px;
    min-height: 22px;
}
.status.good { border-color: var(--good); color: var(--good); }
.status.warn { border-color: var(--warn); color: var(--warn); }
.status.bad  { border-color: var(--bad);  color: var(--bad); }

.log {
    background: var(--bg-elev);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 12px;
    font-family: var(--mono);
    font-size: 12px;
    color: var(--text-dim);
    max-height: 220px;
    overflow-y: auto;
    margin-top: 12px;
}
.log .log-line { padding: 2px 0; border-bottom: 1px dashed rgba(255,255,255,0.04); }
.log .log-line:last-child { border-bottom: none; }
.log .log-time { color: var(--accent); margin-right: 6px; }
.log .log-info { color: var(--text-dim); }
.log .log-ok   { color: var(--good); }
.log .log-err  { color: var(--bad); }
.log .log-warn { color: var(--warn); }

/* ---- Progress bar ---- */
.progress {
    height: 10px;
    background: var(--bg-elev);
    border: 1px solid var(--border);
    border-radius: 999px;
    overflow: hidden;
    margin-top: 8px;
}
.progress-bar {
    height: 100%;
    background: linear-gradient(90deg, var(--accent), var(--accent-2));
    transition: width .25s;
    width: 0%;
}

/* ---- Spectrum visualizer ---- */
.spectrum {
    width: 100%;
    height: 140px;
    background: var(--bg-elev);
    border: 1px solid var(--border);
    border-radius: 8px;
    display: block;
}

/* ---- Inbox (received items) ---- */
.inbox { display: grid; gap: 10px; }
.inbox-item {
    background: var(--bg-elev);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 12px 14px;
    display: flex;
    align-items: flex-start;
    gap: 10px;
}
.inbox-item .icon { font-size: 22px; flex-shrink: 0; }
.inbox-item .body { flex: 1; min-width: 0; }
.inbox-item .meta {
    font-family: var(--mono);
    font-size: 11px;
    color: var(--text-dim);
    margin-bottom: 4px;
}
.inbox-item .content {
    color: var(--text);
    font-size: 14px;
    word-break: break-word;
}
.inbox-item img.preview {
    max-width: 200px;
    max-height: 200px;
    border-radius: 6px;
    margin-top: 8px;
    display: block;
}
.inbox-item .actions { display: flex; gap: 6px; flex-wrap: wrap; margin-top: 6px; }
.inbox-item a.dl-link {
    color: var(--accent);
    text-decoration: none;
    font-size: 13px;
    padding: 4px 10px;
    border: 1px solid var(--accent);
    border-radius: 6px;
}
.inbox-item a.dl-link:hover { background: rgba(56,232,255,0.1); }

.empty-state {
    text-align: center;
    color: var(--text-dim);
    padding: 24px;
    font-size: 14px;
    font-style: italic;
}

/* ---- Hero / Landing ---- */
.hero {
    text-align: center;
    padding: 24px 0 8px;
}
.hero h1 { font-size: 38px; margin-bottom: 8px; }
.hero p { color: var(--text-dim); font-size: 16px; max-width: 580px; margin: 0 auto 16px; }

.feature-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
    gap: 10px;
    margin: 16px 0;
}
.feature {
    background: var(--bg-soft);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 12px;
    font-size: 13px;
    color: var(--text-dim);
    text-align: center;
}
.feature .icon { font-size: 22px; display: block; margin-bottom: 4px; }

/* ---- Settings collapse ---- */
details.settings {
    background: var(--bg-soft);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 8px 16px;
    margin-bottom: 16px;
}
details.settings summary {
    cursor: pointer;
    font-weight: 600;
    padding: 6px 0;
    color: var(--text-dim);
    font-size: 14px;
    list-style: none;
}
details.settings summary::-webkit-details-marker { display: none; }
details.settings summary::before {
    content: "▸";
    display: inline-block;
    margin-right: 8px;
    transition: transform .15s;
}
details.settings[open] summary::before { transform: rotate(90deg); }
details.settings[open] summary { color: var(--accent); }
.settings-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: 12px;
    padding: 12px 0 8px;
}

/* ---- Pill / Badge ---- */
.pill {
    display: inline-block;
    background: rgba(56,232,255,0.1);
    color: var(--accent);
    padding: 2px 8px;
    border-radius: 999px;
    font-size: 11px;
    font-family: var(--mono);
    margin-left: 6px;
}
.pill.live { background: rgba(74,222,128,0.1); color: var(--good); }
.pill.live::before {
    content: "●";
    margin-right: 4px;
    animation: pulse 1.4s ease-in-out infinite;
}
@keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.3; }
}

/* ---- Responsive ---- */
@media (max-width: 600px) {
    h1 { font-size: 26px; }
    .container { padding: 20px 14px 40px; }
    .top-bar { padding: 12px 14px; }
    .top-bar nav { gap: 12px; }
    .card { padding: 14px; }
}