:root {
    --bg-color: #090b10;
    --panel: #11151d;
    --panel-strong: #151b26;
    --field: #090d14;
    --field-raised: #0e1420;
    --text-primary: #f8fafc;
    --text-secondary: #9aa7b8;
    --text-muted: #687589;
    --accent: #19c6b3;
    --accent-hover: #5eead4;
    --accent-soft: rgba(25, 198, 179, 0.13);
    --amber: #f5b84b;
    --amber-soft: rgba(245, 184, 75, 0.13);
    --coral: #f07167;
    --border: rgba(148, 163, 184, 0.18);
    --border-strong: rgba(148, 163, 184, 0.28);
    --error: #fb7185;
    --error-soft: rgba(251, 113, 133, 0.12);
    --shadow: 0 30px 90px rgba(0, 0, 0, 0.42);
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    -webkit-tap-highlight-color: transparent;
}

body {
    align-items: center;
    background:
        linear-gradient(135deg, rgba(25, 198, 179, 0.16), transparent 34%),
        linear-gradient(315deg, rgba(240, 113, 103, 0.13), transparent 32%),
        linear-gradient(180deg, #10131b 0%, var(--bg-color) 64%);
    color: var(--text-primary);
    display: flex;
    font-family: Inter, 'Segoe UI', system-ui, -apple-system, sans-serif;
    justify-content: center;
    min-height: 100vh;
    padding: 18px;
    padding-bottom: max(18px, env(safe-area-inset-bottom));
    padding-top: max(18px, env(safe-area-inset-top));
}

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

.container {
    background:
        linear-gradient(180deg, rgba(255, 255, 255, 0.05), transparent 42%),
        var(--panel);
    border: 1px solid var(--border);
    border-radius: 8px;
    box-shadow: var(--shadow);
    max-width: 1080px;
    overflow: hidden;
    position: relative;
    width: 100%;
}

.container::before {
    background: linear-gradient(90deg, var(--accent), var(--amber), var(--coral));
    content: "";
    height: 3px;
    inset: 0 0 auto;
    position: absolute;
}

header {
    align-items: flex-start;
    border-bottom: 1px solid var(--border);
    display: grid;
    gap: 1rem;
    grid-template-columns: auto minmax(0, 1fr) auto;
    justify-content: initial;
    padding: 1.35rem 1.5rem 1.1rem;
}

.back-btn {
    align-items: center;
    align-self: flex-start;
    background: var(--field-raised);
    border: 1px solid var(--border);
    border-radius: 8px;
    color: var(--text-secondary);
    display: inline-flex;
    height: 38px;
    justify-content: center;
    text-decoration: none;
    transition: background-color 0.18s, border-color 0.18s, color 0.18s;
    width: 38px;
}

.back-btn:hover,
.back-btn:focus-visible {
    background: var(--accent-soft);
    border-color: rgba(94, 234, 212, 0.38);
    color: var(--accent-hover);
}

.back-btn:focus-visible {
    outline: 3px solid rgba(94, 234, 212, 0.28);
    outline-offset: 3px;
}

.back-btn svg {
    height: 18px;
    width: 18px;
}

h1 {
    color: var(--text-primary);
    font-size: 1.6rem;
    font-weight: 760;
    letter-spacing: 0;
    line-height: 1.12;
    margin-bottom: 0.38rem;
}

.subtitle {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.status-line {
    align-items: center;
    color: var(--text-muted);
    display: flex;
    flex: 0 0 auto;
    font-size: 0.82rem;
    gap: 0.45rem;
    min-height: 1.25rem;
    padding-top: 0.15rem;
}

.status-dot {
    background: var(--accent);
    border-radius: 50%;
    box-shadow: 0 0 0 4px rgba(25, 198, 179, 0.12);
    height: 7px;
    width: 7px;
}

.status-line.error .status-dot {
    background: var(--error);
    box-shadow: 0 0 0 4px rgba(251, 113, 133, 0.12);
}

.workspace {
    display: grid;
    gap: 1rem;
    grid-template-columns: minmax(280px, 0.85fr) minmax(0, 1.35fr);
    padding: 1.25rem;
}

.panel {
    background:
        linear-gradient(180deg, rgba(255, 255, 255, 0.035), transparent),
        var(--panel-strong);
    border: 1px solid var(--border);
    border-radius: 8px;
    min-width: 0;
    padding: 1rem;
}

label,
.mode-label {
    align-items: center;
    color: var(--text-secondary);
    display: flex;
    font-size: 0.76rem;
    font-weight: 760;
    justify-content: space-between;
    letter-spacing: 0;
    margin-bottom: 0.72rem;
    text-transform: uppercase;
}

label:not(:first-child),
.mode-label {
    margin-top: 1rem;
}

label span:last-child,
.mode-label span:last-child {
    color: var(--accent-hover);
    font-size: 0.72rem;
    text-transform: none;
}

.control-grid {
    display: grid;
    gap: 0.7rem;
    grid-template-columns: 138px minmax(0, 1fr);
}

input,
select,
textarea {
    background-color: var(--field);
    border: 1px solid var(--border);
    border-radius: 8px;
    color: var(--text-primary);
    outline: none;
    transition: border-color 0.18s, box-shadow 0.18s, background-color 0.18s;
    width: 100%;
}

input,
select {
    min-height: 52px;
    padding: 0 0.85rem;
}

select {
    appearance: none;
    background-image: url("data:image/svg+xml;charset=UTF-8,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%239aa7b8' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3e%3cpolyline points='6 9 12 15 18 9'%3e%3c/polyline%3e%3c/svg%3e");
    background-position: right 12px center;
    background-repeat: no-repeat;
    background-size: 16px;
    cursor: pointer;
    font-weight: 700;
    padding-right: 2rem;
}

select option {
    background-color: #111827;
    color: var(--text-primary);
}

textarea {
    line-height: 1.55;
    min-height: 116px;
    padding: 0.85rem;
    resize: vertical;
}

input::placeholder,
textarea::placeholder {
    color: rgba(154, 167, 184, 0.46);
}

input:focus,
select:focus,
textarea:focus {
    border-color: rgba(94, 234, 212, 0.78);
    box-shadow: 0 0 0 3px rgba(25, 198, 179, 0.14);
}

.mode-toggle {
    background: var(--field);
    border: 1px solid var(--border);
    border-radius: 8px;
    display: grid;
    gap: 0.35rem;
    grid-template-columns: 1fr 1fr;
    padding: 0.35rem;
}

.mode-btn,
.action-btn {
    border: 0;
    border-radius: 8px;
    cursor: pointer;
    font-weight: 760;
    min-height: 42px;
    transition: background-color 0.18s, border-color 0.18s, color 0.18s, transform 0.18s;
}

.mode-btn {
    background: transparent;
    color: var(--text-secondary);
}

.mode-btn:hover,
.mode-btn.active {
    background: var(--accent-soft);
    color: var(--accent-hover);
}

.action-row {
    display: grid;
    gap: 0.65rem;
    grid-template-columns: 1fr 1fr;
    margin-top: 1rem;
}

.action-btn {
    background: linear-gradient(135deg, var(--accent), #2dd4bf);
    color: #04110f;
}

.action-btn:hover {
    transform: translateY(-1px);
}

.action-btn.secondary {
    background: var(--field-raised);
    border: 1px solid var(--border);
    color: var(--text-secondary);
}

.action-btn:focus-visible,
.mode-btn:focus-visible {
    outline: 3px solid rgba(94, 234, 212, 0.28);
    outline-offset: 3px;
}

.hint-box {
    background: rgba(25, 198, 179, 0.07);
    border: 1px solid rgba(94, 234, 212, 0.18);
    border-radius: 8px;
    color: var(--text-secondary);
    font-size: 0.82rem;
    line-height: 1.55;
    margin-top: 1rem;
    padding: 0.8rem;
}

.summary {
    align-items: center;
    border-bottom: 1px solid var(--border);
    display: flex;
    gap: 1rem;
    justify-content: space-between;
    margin: -0.1rem 0 1rem;
    padding-bottom: 0.9rem;
}

.summary-title {
    color: var(--text-secondary);
    font-size: 0.76rem;
    font-weight: 760;
    letter-spacing: 0;
    text-transform: uppercase;
}

.summary-value {
    color: var(--accent-hover);
    font-size: 0.82rem;
    font-weight: 720;
    text-align: right;
}

.result-grid {
    display: grid;
    gap: 0.75rem;
    grid-template-columns: 1fr 1fr;
}

.result-card {
    background: var(--field-raised);
    border: 1px solid var(--border);
    border-radius: 8px;
    min-width: 0;
    padding: 0.8rem;
}

.result-card.wide {
    grid-column: 1 / -1;
}

.result-label {
    color: var(--text-muted);
    display: block;
    font-size: 0.68rem;
    font-weight: 760;
    letter-spacing: 0.06em;
    margin-bottom: 0.5rem;
    text-transform: uppercase;
}

.result-value {
    color: var(--text-primary);
    font-family: 'Cascadia Mono', 'SFMono-Regular', Consolas, 'Courier New', monospace;
    font-size: 0.94rem;
    line-height: 1.55;
    overflow-wrap: anywhere;
}

.result-value.expression {
    color: var(--accent-hover);
}

.table-wrap {
    margin-top: 1rem;
    overflow-x: auto;
}

.truth-table {
    border-collapse: collapse;
    min-width: 100%;
}

.truth-table th,
.truth-table td {
    border-bottom: 1px solid var(--border);
    color: var(--text-secondary);
    font-family: 'Cascadia Mono', 'SFMono-Regular', Consolas, 'Courier New', monospace;
    font-size: 0.82rem;
    padding: 0.62rem 0.7rem;
    text-align: center;
}

.truth-table th {
    color: var(--text-muted);
    font-family: Inter, 'Segoe UI', system-ui, -apple-system, sans-serif;
    font-size: 0.68rem;
    font-weight: 760;
    letter-spacing: 0.06em;
    text-transform: uppercase;
}

.truth-table td.output-one {
    color: var(--accent-hover);
    font-weight: 760;
}

.truth-table td.output-zero {
    color: #f59d97;
    font-weight: 760;
}

.output-toggle {
    align-items: center;
    border: 1px solid var(--border);
    border-radius: 8px;
    cursor: pointer;
    display: inline-flex;
    font-family: 'Cascadia Mono', 'SFMono-Regular', Consolas, 'Courier New', monospace;
    font-size: 0.86rem;
    font-weight: 780;
    height: 34px;
    justify-content: center;
    min-width: 46px;
    transition: background-color 0.18s, border-color 0.18s, color 0.18s, transform 0.18s;
}

.output-toggle:hover {
    transform: translateY(-1px);
}

.output-toggle:focus-visible {
    outline: 3px solid rgba(94, 234, 212, 0.28);
    outline-offset: 3px;
}

.output-toggle.is-one {
    background: var(--accent-soft);
    border-color: rgba(94, 234, 212, 0.38);
    color: var(--accent-hover);
}

.output-toggle.is-zero {
    background: rgba(240, 113, 103, 0.08);
    border-color: rgba(240, 113, 103, 0.22);
    color: #f59d97;
}

.empty-state {
    align-items: center;
    background: rgba(148, 163, 184, 0.05);
    border: 1px dashed var(--border-strong);
    border-radius: 8px;
    color: var(--text-muted);
    display: flex;
    font-size: 0.9rem;
    justify-content: center;
    min-height: 160px;
    padding: 1rem;
    text-align: center;
}

@media (max-width: 900px) {
    body {
        align-items: flex-start;
    }

    .workspace {
        grid-template-columns: 1fr;
    }


}

@media (max-width: 560px) {
    body {
        padding-left: 12px;
        padding-right: 12px;
    }

    header {
        display: block;
        padding: 1.2rem 1rem 1rem;
    }

    .status-line {
        margin-top: 0.85rem;
    }

    .workspace {
        padding: 1rem;
    }

    .control-grid,
    .result-grid {
        grid-template-columns: 1fr;
    }

    h1 {
        font-size: 1.35rem;
    }
    
    .back-btn {
        display: none;
    }
}