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

:root {
    --bg: #0a0f1e;
    --bg2: #0d1528;
    --accent: #00b4d8;
    --accent2: #0077b6;
    --accent-glow: rgba(0, 180, 216, 0.15);
    --accent-glow2: rgba(0, 180, 216, 0.08);
    --text-white: #e8edf5;
    --text-muted: #7b8ba3;
    --card-bg: #ffffff;
    --card-border: #e2e8f0;
    --text-dark: #1e293b;
    --text-mid: #475569;
    --text-light: #94a3b8;
    --green: #22c55e;
    --amber: #f59e0b;
    --red: #ef4444;
    --radius: 16px;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    background: var(--bg);
    color: var(--text-white);
    min-height: 100vh;
    line-height: 1.6;
}

/* ── Circuit Background ── */
.circuit-bg {
    position: fixed; inset: 0; z-index: 0; pointer-events: none; overflow: hidden;
}
.circuit-bg::before {
    content: ''; position: absolute; inset: 0;
    background:
        linear-gradient(90deg, transparent 49.5%, rgba(0,180,216,0.04) 49.5%, rgba(0,180,216,0.04) 50.5%, transparent 50.5%),
        linear-gradient(0deg,  transparent 49.5%, rgba(0,180,216,0.04) 49.5%, rgba(0,180,216,0.04) 50.5%, transparent 50.5%);
    background-size: 50px 50px;
}
.circuit-bg::after {
    content: ''; position: absolute; inset: 0;
    background:
        radial-gradient(ellipse at 30% 0%,   rgba(0,180,216,0.08) 0%, transparent 50%),
        radial-gradient(ellipse at 70% 100%,  rgba(0,119,182,0.06) 0%, transparent 50%),
        radial-gradient(circle  at 50% 50%,   rgba(0,180,216,0.03) 0%, transparent 70%);
}
.circuit-nodes { position: fixed; inset: 0; z-index: 0; pointer-events: none; }
.node { position: absolute; width: 6px; height: 6px; background: var(--accent); border-radius: 50%; opacity: 0.08; }
.node:nth-child(1) { top: 100px; left: 100px; }
.node:nth-child(2) { top: 100px; left: 300px; }
.node:nth-child(3) { top: 100px; right: 200px; }
.node:nth-child(4) { top: 250px; left: 50px; }
.node:nth-child(5) { top: 250px; right: 150px; }
.node:nth-child(6) { top: 400px; left: 200px; }
.node:nth-child(7) { top: 400px; right: 100px; }
.node:nth-child(8) { top: 550px; left: 150px; }

/* ── App Container ── */
.app-container {
    position: relative; z-index: 1;
    max-width: 800px; margin: 0 auto; padding: 1.5rem;
}

/* ── Header ── */
.header {
    display: flex; align-items: center; justify-content: space-between;
    gap: 1rem; padding: 0.75rem 0;
}
.header-brand { flex: 1; min-width: 0; }
.header h1 {
    font-size: 1.75rem; font-weight: 800; color: var(--text-white);
    letter-spacing: -0.02em; text-shadow: 0 0 30px rgba(0,180,216,0.3);
}
.header h1 .accent { color: var(--accent); }
.header .subtitle {
    font-size: 0.85rem; color: var(--text-muted); margin-top: 0.2rem;
}
.header-attribution {
    display: block; font-size: 0.72rem; color: var(--text-muted);
    margin-top: 0.25rem; opacity: 0.8;
}
.header-attribution strong { color: var(--accent); font-weight: 600; }

/* ── Header Nav ── */
.header-nav { display: flex; align-items: center; gap: 0.5rem; flex-shrink: 0; }
.header-nav-link {
    display: inline-flex; align-items: center; gap: 0.35rem;
    padding: 0.45rem 0.875rem;
    background: rgba(255,255,255,0.07);
    border: 1px solid rgba(255,255,255,0.12);
    border-radius: 8px;
    color: var(--text-white);
    font-size: 0.8rem; font-weight: 600; font-family: inherit;
    cursor: pointer; text-decoration: none; white-space: nowrap;
    transition: background 0.2s, border-color 0.2s, color 0.2s;
}
.header-nav-link:hover {
    background: rgba(0,180,216,0.12);
    border-color: rgba(0,180,216,0.4);
    color: var(--accent);
}

/* ── Main Card ── */
.main-card {
    background: var(--card-bg);
    border-radius: var(--radius);
    box-shadow: 0 4px 24px rgba(0,0,0,0.3), 0 0 0 1px rgba(0,180,216,0.08);
    overflow: hidden;
}

/* ── Category Tabs ── */
.category-tabs { display: flex; background: #f1f5f9; border-bottom: 1px solid var(--card-border); }
.cat-tab {
    flex: 1; padding: 0.65rem 1rem; background: none; border: none;
    font-size: 0.9rem; font-weight: 700; color: var(--text-light); cursor: pointer;
    transition: all 0.2s; font-family: inherit;
    border-bottom: 3px solid transparent;
    text-transform: uppercase; letter-spacing: 0.04em;
}
.cat-tab:hover { color: var(--text-mid); background: #e8edf5; }
.cat-tab.active { color: var(--accent2); background: var(--card-bg); border-bottom-color: var(--accent); }

/* ── Form Area ── */
.form-area { padding: 1rem 1.25rem 1.1rem; }
.step-label {
    font-size: 0.7rem; font-weight: 700; text-transform: uppercase;
    letter-spacing: 0.06em; color: var(--text-light); margin-bottom: 0.3rem;
    display: flex; align-items: center; gap: 0.4rem;
}
.form-group { margin-bottom: 0.875rem; }
.form-select, .form-input {
    width: 100%; padding: 0.6rem 0.875rem;
    border: 2px solid var(--card-border); border-radius: 10px;
    font-size: 0.95rem; font-family: inherit; color: var(--text-dark);
    background: var(--card-bg); outline: none;
    transition: border-color 0.2s, box-shadow 0.2s;
}
.form-select:focus, .form-input:focus {
    border-color: var(--accent); box-shadow: 0 0 0 3px var(--accent-glow);
}
.form-select:disabled, .form-input:disabled {
    background: #f1f5f9; color: var(--text-light); cursor: not-allowed;
}
.helper-text { font-size: 0.78rem; color: var(--text-light); margin-top: 0.3rem; }

/* ── Era Dropdown & Note ── */
.info-icon {
    display: inline-flex; align-items: center; justify-content: center;
    width: 16px; height: 16px; border-radius: 50%;
    background: var(--accent); color: #fff;
    font-size: 0.62rem; font-weight: 700; cursor: help;
    font-style: normal; flex-shrink: 0;
}
.era-note {
    font-size: 0.78rem;
    color: #555;
    margin-top: 0.5rem;
    line-height: 1.5;
    font-style: italic;
}

/* ── Decode Button ── */
.decode-btn {
    width: 100%; padding: 0.7rem;
    background: linear-gradient(135deg, var(--accent) 0%, var(--accent2) 100%);
    color: #fff; border: none; border-radius: 10px;
    font-size: 1rem; font-weight: 700; font-family: inherit;
    cursor: pointer; transition: all 0.2s;
    box-shadow: 0 4px 12px rgba(0,180,216,0.25); margin-top: 0.5rem;
}
.decode-btn:hover:not(:disabled) {
    transform: translateY(-1px); box-shadow: 0 6px 20px rgba(0,180,216,0.35);
}
.decode-btn:disabled { background: #cbd5e1; cursor: not-allowed; box-shadow: none; }

/* ── Alt Lookup Toggle ── */
.alt-toggle {
    display: inline-flex; align-items: center; gap: 0.35rem;
    color: var(--accent); font-size: 0.8rem; font-weight: 600;
    cursor: pointer; user-select: none; margin-top: 0.5rem; transition: color 0.2s;
}
.alt-toggle:hover { color: var(--accent2); }
.alt-toggle .arrow { display: inline-block; transition: transform 0.3s ease; font-size: 0.55rem; }
.alt-toggle.open .arrow { transform: rotate(90deg); }

.alt-section { max-height: 0; opacity: 0; overflow: hidden; transition: max-height 0.35s ease, opacity 0.35s ease; }
.alt-section.open { max-height: 700px; opacity: 1; }

.alt-inner {
    background: #f4f4f4; border-radius: 12px;
    padding: 0.875rem 1rem; margin-top: 0.25rem;
}
.alt-divider {
    display: flex; align-items: center; gap: 0.75rem; margin-bottom: 0.75rem;
}
.alt-divider::before, .alt-divider::after {
    content: ''; flex: 1; height: 1px; background: var(--card-border);
}
.alt-divider span {
    font-size: 0.7rem; font-weight: 600; color: var(--text-light);
    text-transform: uppercase; letter-spacing: 0.08em;
}

/* ── Alt Scope Note (electronics coverage) ── */
.alt-scope-note {
    font-size: 0.78rem; color: var(--accent);
    background: rgba(0,180,216,0.07);
    border: 1px solid rgba(0,180,216,0.2);
    border-radius: 6px; padding: 0.45rem 0.7rem;
    margin-bottom: 0.6rem; line-height: 1.5;
}
.alt-scope-note strong { color: var(--accent); }

/* ── Alt Disclaimer (dark text for readability) ── */
.alt-disclaimer {
    font-size: 0.8rem;
    color: #333333;
    background: #fff;
    border: 1px solid var(--card-border);
    border-left: 3px solid var(--accent);
    border-radius: 8px;
    padding: 0.75rem 0.875rem;
    margin-bottom: 0.875rem;
    line-height: 1.55;
}

/* ── Loading Animation ── */
.loading-inner {
    display: flex; flex-direction: column; align-items: center;
    justify-content: center; padding: 2rem 1.5rem; gap: 0.75rem;
}
.loading-emoji { font-size: 2.75rem; line-height: 1; display: block; }
.loading-emoji.lightning { animation: flicker 0.75s infinite; }
.loading-emoji.sun        { animation: sunPop 0.5s ease forwards; }
@keyframes flicker {
    0%, 100% { opacity: 1;   transform: scale(1);    }
    25%       { opacity: 0.4; transform: scale(0.93); }
    50%       { opacity: 1;   transform: scale(1.07); }
    75%       { opacity: 0.6; transform: scale(1);    }
}
@keyframes sunPop {
    0%   { transform: scale(0.4) rotate(-15deg); opacity: 0; }
    65%  { transform: scale(1.2) rotate(5deg);   opacity: 1; }
    100% { transform: scale(1)   rotate(0deg);   opacity: 1; }
}
.loading-text {
    text-align: center; color: var(--text-light);
    font-style: italic; font-size: 0.9rem;
}

/* ── Results Cards ── */
.results-card {
    margin-top: 1.5rem; background: var(--card-bg);
    border-radius: var(--radius);
    box-shadow: 0 4px 24px rgba(0,0,0,0.3), 0 0 0 1px rgba(0,180,216,0.08);
    overflow: hidden;
}
.results-header {
    background: linear-gradient(135deg, #0d2847 0%, #1a3a5c 100%);
    padding: 1rem 1.5rem;
    display: flex; align-items: center; justify-content: space-between; gap: 0.5rem;
}
.results-header h3 { font-size: 1rem; font-weight: 700; color: var(--text-white); }
.results-body { padding: 1.5rem; }

.result-row {
    display: flex; justify-content: space-between; align-items: center;
    padding: 0.85rem 1rem; margin-bottom: 0.5rem;
    background: #f8fafc; border-radius: 10px; border-left: 4px solid var(--accent);
}
.result-label { font-size: 0.85rem; font-weight: 600; color: var(--text-mid); }
.result-value { font-size: 1.05rem; font-weight: 700; color: var(--accent2); }

.info-block {
    margin-top: 1rem; padding: 1rem; background: #f8fafc;
    border-radius: 10px; border-left: 4px solid var(--card-border);
}
.info-block.method      { border-left-color: var(--amber); background: #fffbeb; }
.info-block.notes       { border-left-color: var(--red);   background: #fef2f2; }
.info-block.sources     { border-left-color: var(--green);  background: #f0fdf4; }
.info-block.serial-loc  { border-left-color: #6366f1; background: #f5f3ff; }
.info-block.serial-rule { border-left-color: var(--accent); background: #ecfeff; }
.info-block h4 {
    font-size: 0.78rem; font-weight: 700; color: var(--text-mid);
    text-transform: uppercase; letter-spacing: 0.05em; margin-bottom: 0.4rem;
}
.info-block p { font-size: 0.85rem; color: var(--text-mid); line-height: 1.6; }

/* ── Brand Logo ── */
.brand-logo-wrap {
    display: none; align-items: center; justify-content: flex-end; min-width: 44px;
}
.brand-logo {
    height: 32px; max-width: 80px; object-fit: contain;
    filter: brightness(0) invert(1); opacity: 0.88;
}
.brand-badge {
    display: inline-flex; align-items: center; justify-content: center;
    width: 34px; height: 34px; border-radius: 8px;
    background: rgba(255,255,255,0.18); color: #fff;
    font-size: 0.75rem; font-weight: 800; letter-spacing: 0.02em;
}

/* ── Confidence Badge & Bar ── */
.confidence-badge {
    display: inline-block; padding: 0.15rem 0.5rem;
    border-radius: 4px; font-size: 0.7rem; font-weight: 700; text-transform: uppercase;
}
.confidence-badge.high   { background: #dcfce7; color: #166534; }
.confidence-badge.medium { background: #fef9c3; color: #854d0e; }
.confidence-badge.low    { background: #fef2f2; color: #991b1b; }

.confidence-bar-wrap { margin: 0.875rem 0 0.25rem; }
.confidence-bar-label {
    font-size: 0.7rem; font-weight: 700; text-transform: uppercase;
    letter-spacing: 0.06em; color: var(--text-light); margin-bottom: 0.4rem;
}
.confidence-bar { display: flex; gap: 4px; }
.conf-seg {
    flex: 1; padding: 0.42rem 0; text-align: center;
    font-size: 0.72rem; font-weight: 700;
    background: #e2e8f0; color: var(--text-light);
    border-radius: 5px; transition: background 0.25s, color 0.25s;
}
.conf-seg.active.low    { background: #fee2e2; color: #991b1b; }
.conf-seg.active.medium { background: #fef9c3; color: #854d0e; }
.conf-seg.active.high   { background: #dcfce7; color: #166534; }

/* ── Evidence List ── */
.evidence-list { margin-top: 1rem; }
.evidence-item {
    padding: 0.6rem 0.75rem; margin-bottom: 0.35rem;
    background: #f8fafc; border-radius: 8px;
    font-size: 0.82rem; color: var(--text-mid); display: flex; gap: 0.5rem;
}
.evidence-item .ev-source { font-weight: 700; color: var(--text-dark); white-space: nowrap; }
.evidence-item .ev-date   { color: var(--accent2); font-weight: 600; white-space: nowrap; }

/* ── "Possible Error?" Button ── */
.results-footer {
    padding: 0.75rem 1.5rem 1.25rem;
    display: flex; justify-content: center;
}
.error-btn {
    display: inline-flex; align-items: center; gap: 0.4rem;
    background: #fff7ed;
    border: 2px solid #fb923c;
    border-radius: 10px;
    padding: 0.65rem 1.5rem;
    font-size: 0.88rem; font-weight: 700;
    color: #c2410c;
    cursor: pointer; font-family: inherit;
    transition: all 0.18s;
    width: 100%; justify-content: center;
    box-shadow: 0 2px 6px rgba(249,115,22,0.15);
}
.error-btn:hover {
    background: #ffedd5; border-color: #ea580c; color: #9a3412;
    box-shadow: 0 4px 12px rgba(249,115,22,0.25);
    transform: translateY(-1px);
}

/* ── Footer ── */
.footer {
    text-align: center; padding: 2rem 1rem;
    color: var(--text-muted); font-size: 0.75rem; line-height: 1.6;
}
.footer a { color: var(--accent); text-decoration: none; }

.hidden { display: none !important; }

/* ── Guide Drawer ── */
.guide-overlay {
    position: fixed; inset: 0; z-index: 900;
    background: rgba(0,0,0,0.45);
    opacity: 0; pointer-events: none;
    transition: opacity 0.3s;
    backdrop-filter: blur(2px);
}
.guide-overlay.open { opacity: 1; pointer-events: all; }

.guide-drawer {
    position: fixed; top: 0; left: -110%; bottom: 0;
    width: min(380px, 92vw); z-index: 910;
    background: #fff; overflow-y: auto;
    box-shadow: 6px 0 32px rgba(0,0,0,0.25);
    transition: left 0.32s cubic-bezier(0.4, 0, 0.2, 1);
    display: flex; flex-direction: column;
}
.guide-drawer.open { left: 0; }

.guide-drawer-header {
    display: flex; align-items: center; justify-content: space-between;
    background: linear-gradient(135deg, #0d2847 0%, #1a3a5c 100%);
    padding: 1.1rem 1.25rem;
    position: sticky; top: 0; z-index: 1;
}
.guide-drawer-header h3 { font-size: 1rem; font-weight: 700; color: var(--text-white); }
.guide-drawer-close {
    background: none; border: none; color: rgba(255,255,255,0.7);
    font-size: 1.1rem; cursor: pointer; padding: 0.2rem 0.45rem;
    border-radius: 4px; transition: background 0.2s; line-height: 1;
}
.guide-drawer-close:hover { background: rgba(255,255,255,0.12); color: #fff; }

.guide-drawer-body {
    padding: 1.5rem;
    color: var(--text-mid); font-size: 0.875rem; line-height: 1.7;
}
.guide-drawer-body h4 {
    color: var(--text-dark); font-size: 0.95rem;
    margin: 1.25rem 0 0.5rem;
}
.guide-drawer-body h4:first-child { margin-top: 0; }
.guide-drawer-body ol,
.guide-drawer-body ul { margin-left: 1.25rem; margin-bottom: 0.75rem; }
.guide-drawer-body li { margin-bottom: 0.35rem; }
.guide-drawer-body strong { color: var(--text-dark); }
.guide-drawer-body p { margin-bottom: 0.75rem; }
.warning-note {
    background: #fffbeb; border-left: 3px solid var(--amber);
    padding: 0.75rem 1rem; border-radius: 8px;
    margin: 0.75rem 0; color: #92400e; font-size: 0.82rem;
}

/* ── Feedback Modal ── */
.modal-overlay {
    position: fixed; inset: 0; z-index: 1000;
    background: rgba(0,0,0,0.58);
    display: flex; align-items: center; justify-content: center;
    padding: 1rem; backdrop-filter: blur(4px);
}
.modal-overlay.hidden { display: none !important; }
.modal-card {
    background: var(--card-bg); border-radius: var(--radius);
    box-shadow: 0 24px 64px rgba(0,0,0,0.45);
    width: 100%; max-width: 440px; overflow: hidden;
    animation: modalIn 0.22s ease;
}
@keyframes modalIn {
    from { transform: translateY(14px) scale(0.97); opacity: 0; }
    to   { transform: translateY(0)    scale(1);    opacity: 1; }
}
.modal-header {
    display: flex; align-items: center; justify-content: space-between;
    background: linear-gradient(135deg, #0d2847 0%, #1a3a5c 100%);
    padding: 1rem 1.25rem;
}
.modal-header h3 { font-size: 1rem; font-weight: 700; color: var(--text-white); }
.modal-close {
    background: none; border: none; color: rgba(255,255,255,0.65);
    font-size: 1.1rem; cursor: pointer; padding: 0.2rem 0.45rem;
    border-radius: 4px; transition: background 0.2s, color 0.2s; line-height: 1;
}
.modal-close:hover { background: rgba(255,255,255,0.12); color: #fff; }
.modal-body { padding: 1.25rem; }
.modal-field { margin-bottom: 0.875rem; }
.modal-field label {
    display: block; font-size: 0.7rem; font-weight: 700;
    text-transform: uppercase; letter-spacing: 0.06em;
    color: var(--text-light); margin-bottom: 0.3rem;
}
.modal-field input[readonly] { background: #f8fafc; color: var(--text-mid); }
.modal-field textarea.form-input { resize: vertical; min-height: 72px; }
.modal-actions { display: flex; gap: 0.75rem; margin-top: 1rem; }
.modal-actions .decode-btn { flex: 1; margin-top: 0; }
.cancel-btn {
    flex: 0 0 auto; padding: 0.85rem 1.25rem;
    background: #f1f5f9; border: none; border-radius: 10px;
    font-size: 0.9rem; font-weight: 600; font-family: inherit;
    color: var(--text-mid); cursor: pointer; transition: background 0.2s;
}
.cancel-btn:hover { background: #e2e8f0; }
.fb-thanks {
    background: #f0fdf4; border: 1px solid #bbf7d0; border-radius: 8px;
    padding: 0.75rem 1rem; color: #166534; font-size: 0.85rem;
    font-weight: 600; margin-bottom: 0.875rem; text-align: center;
}

/* ── Responsive ── */

@media (max-width: 768px) {
    .app-container { padding: 0.75rem; }
    .header { flex-wrap: wrap; }
    .header h1 { font-size: 1.4rem; }
    .header-nav { gap: 0.35rem; }
    .header-nav-link { font-size: 0.75rem; padding: 0.4rem 0.65rem; }
    .form-area { padding: 1rem; }
    .results-body { padding: 1rem; }
    .result-row { flex-direction: column; align-items: flex-start; gap: 0.3rem; }
}

@media (max-width: 600px) {
    .decode-btn    { padding: 1rem; font-size: 1.05rem; min-height: 52px; }
    .cat-tab       { padding: 0.9rem 0.5rem; font-size: 0.8rem; }
    .form-select,
    .form-input    { padding: 0.875rem 1rem; font-size: 1rem; min-height: 50px; }
    .modal-card    { max-width: 100%; }
    .modal-body    { padding: 1rem; }
    .brand-logo    { height: 28px; }
    .error-btn     { font-size: 0.9rem; padding: 0.75rem 1rem; }
}