:root {
    /* Paleta Escura - Instrumento Técnico Premium */
    --bg-app: #090a0f;              /* Grafite Escuro Ultra-Profundo */
    --bg-paper: #121318;            /* Preto Carbono Sólido */
    --bg-tabs: #0d0e12;             /* Fundo das abas inativas */
    --bg-tab-active: #121318;       /* Fundo da aba ativa (igual ao papel) */
    --border-color: #212530;        /* Bordas sutis de alta definição */
    --border-color-active: #a3e635; /* Borda ativa em Verde Ácido */

    --text-main: #f1f5f9;           /* Off-white super legível (Slate 100) */
    --text-muted: #64748b;          /* Slate 500 para comentários/linhas inativas */
    --text-positive: #f1f5f9;
    --text-negative: #f87171;       /* Vermelho Coral de precisão */
    --text-result: #f97316;         /* Laranja Sinalizador de destaque */
    --text-comment: #34d399;        /* Verde Sálvia de precisão para comentários */
    --text-variable: #22d3ee;       /* Ciano técnico para variáveis */

    --line-number-color: #475569;   /* Slate 600 */
    --result-line-color: #f97316;   /* Laranja Sinalizador */
    --copy-icon-color: #475569;

    --font-ui: 'Outfit', 'Segoe UI', system-ui, sans-serif;
    --font-mono: 'JetBrains Mono', 'Consolas', monospace;

    --line-h: 30px;                 /* Altura de linha ligeiramente maior para respirar */
    --gutter-w: 42px;               /* Mais espaço para números de linha/cópia */
    --op-w: 30px;                   /* Mais largura para operador */
    --number-w: 150px;              /* Espaço perfeito para alinhamento decimal */
}

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

/* Custom Scrollbars */
::-webkit-scrollbar {
    width: 6px;
    height: 6px;
}
::-webkit-scrollbar-track {
    background: var(--bg-app);
}
::-webkit-scrollbar-thumb {
    background: #212530;
    border-radius: 0px;
}
::-webkit-scrollbar-thumb:hover {
    background: #32384a;
}

body {
    font-family: var(--font-ui);
    background: var(--bg-app);
    color: var(--text-main);
    height: 100vh;
    overflow: hidden;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* App Layout */
.app-container {
    display: flex;
    flex-direction: column;
    height: 100vh;
}

/* ===== TABS BAR ===== */
.tabs-bar {
    display: flex;
    align-items: stretch;
    background: var(--bg-tabs);
    border-bottom: 1px solid var(--border-color);
    height: 42px;
    min-height: 42px;
    padding-left: 12px;
}

.tabs-scroll {
    display: flex;
    align-items: stretch;
    overflow-x: auto;
    flex: 1;
    scrollbar-width: none;
}

.tabs-scroll::-webkit-scrollbar { display: none; }

.tab {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 0 18px;
    font-size: 0.85rem;
    color: var(--text-muted);
    background: transparent;
    border: none;
    border-right: 1px solid var(--border-color);
    cursor: pointer;
    white-space: nowrap;
    position: relative;
    font-family: var(--font-ui);
    transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
}

.tab:hover {
    background: rgba(255, 255, 255, 0.01);
    color: var(--text-main);
}

.tab.active {
    background: var(--bg-tab-active);
    color: var(--text-main);
    font-weight: 600;
}

/* Linha ativa neon na aba */
.tab.active::after {
    content: '';
    position: absolute;
    bottom: -1px;
    left: 0;
    right: 0;
    height: 2px;
    background: var(--border-color-active);
}

.tab-close {
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.95rem;
    line-height: 1;
    color: var(--text-muted);
    background: none;
    border: none;
    cursor: pointer;
    padding: 2px 4px;
    border-radius: 2px;
    transition: all 0.15s;
}

.tab-close:hover {
    background: rgba(248, 113, 113, 0.15);
    color: var(--text-negative);
}

.tab-btn-new {
    display: flex;
    align-items: center;
    justify-content: center;
    background: none;
    border: none;
    border-left: 1px solid var(--border-color);
    padding: 0 16px;
    font-size: 1.3rem;
    cursor: pointer;
    color: var(--text-muted);
    transition: all 0.15s;
}

.tab-btn-new:hover {
    background: rgba(255, 255, 255, 0.02);
    color: var(--border-color-active);
}

/* ===== CONTENT AREA ===== */
.content-area {
    flex: 1;
    display: flex;
    overflow: hidden;
}

.main-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

/* ===== TAPE PAPER ===== */
.tape-scroll {
    flex: 1;
    overflow-y: auto;
    background: var(--bg-paper);
    padding: 0;
}

.tape-paper {
    width: 100%;
    background-color: var(--bg-paper);
    /* Desenha a calha divisória diretamente no papel como uma faixa vertical contínua */
    background-image: linear-gradient(
        to right,
        rgba(255, 255, 255, 0.015) 0px,
        rgba(255, 255, 255, 0.015) calc(var(--gutter-w) + 3px),
        var(--border-color) calc(var(--gutter-w) + 3px),
        var(--border-color) calc(var(--gutter-w) + 4px),
        transparent calc(var(--gutter-w) + 4px)
    );
    border: none;
    box-shadow: none;
    padding: 12px 0;
    min-height: 100%;
    position: relative;
}

/* ===== TAPE LINE ===== */
.tape-line {
    display: flex;
    align-items: center;
    height: var(--line-h);
    padding: 0 16px 0 0;
    position: relative;
    border-left: 3px solid transparent;
    transition: background 0.15s, border-color 0.15s;
    user-select: none;
    -webkit-user-select: none;
}

.tape-line:hover {
    background: rgba(255, 255, 255, 0.008);
}

/* Indicador de linha ativa focada */
.tape-line.editing {
    background: rgba(163, 230, 53, 0.02);
    border-left-color: var(--border-color-active);
}

/* Gutter: line number or copy icon */
.tape-gutter {
    width: var(--gutter-w);
    min-width: var(--gutter-w);
    max-width: var(--gutter-w);
    flex: 0 0 var(--gutter-w);
    text-align: right;
    padding-right: 12px;
    font-family: var(--font-mono);
    font-size: 0.75rem;
    color: var(--line-number-color);
    user-select: none;
    cursor: default;
    background: transparent;
    border-right: none;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: flex-end;
    box-sizing: border-box;
}

.tape-gutter.copy-gutter {
    cursor: pointer;
    color: var(--copy-icon-color);
    font-size: 0.9rem;
    transition: color 0.15s;
}

.tape-gutter.copy-gutter:hover {
    color: var(--text-result);
}

/* Operator column */
.tape-op {
    width: var(--op-w);
    min-width: var(--op-w);
    max-width: var(--op-w);
    flex: 0 0 var(--op-w);
    text-align: center;
    font-family: var(--font-mono);
    font-size: 0.95rem;
    font-weight: 700;
    color: var(--border-color-active); /* Neon acid green */
    user-select: none;
    box-sizing: border-box;
}

.tape-op.negative { color: var(--text-negative); }

/* Number column - right aligned */
.tape-value {
    width: var(--number-w);
    min-width: var(--number-w);
    max-width: var(--number-w);
    flex: 0 0 var(--number-w);
    text-align: right;
    font-family: var(--font-mono);
    font-size: 0.95rem;
    font-weight: 500;
    padding-right: 14px;
    color: var(--text-main);
    box-sizing: border-box;
}

.tape-value.negative { color: var(--text-negative); }

/* Input for editing the line */
.tape-input {
    flex: 1;
    font-family: var(--font-mono);
    font-size: 0.95rem;
    line-height: var(--line-h);
    height: var(--line-h);
    border: none;
    outline: none;
    background: transparent;
    color: var(--text-main);
    padding: 0 4px;
    min-width: 0;
}

.tape-input:focus {
    background: transparent;
}

.tape-input.hidden-input {
    position: absolute;
    width: 1px;
    height: 1px;
    opacity: 0;
    pointer-events: none;
}

/* Comment portion */
.tape-comment {
    flex: 1;
    font-family: var(--font-ui);
    font-size: 0.85rem;
    color: var(--text-comment);
    padding-left: 8px;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

/* ===== RESULT LINE ===== */
.tape-line.result-line {
    margin: 6px 0;
    background: transparent;
    border-left: none !important;
}

.tape-line.result-line:hover {
    background: rgba(255, 255, 255, 0.005);
}

.tape-line.result-line .tape-op,
.tape-line.result-line .tape-value {
    border-top: 1px dashed rgba(249, 115, 22, 0.35); /* Tracinhos laranja com opacidade */
    border-bottom: 1px dashed rgba(249, 115, 22, 0.35); /* Tracinhos laranja com opacidade */
    color: var(--text-main);
}

.tape-line.result-line .tape-value {
    font-weight: 700;
}

.tape-line.result-line.negative .tape-op,
.tape-line.result-line.negative .tape-value {
    color: var(--text-negative);
    border-top: 1px dashed rgba(248, 113, 113, 0.35); /* Tracinhos vermelhos com opacidade */
    border-bottom: 1px dashed rgba(248, 113, 113, 0.35);
}

/* ===== VARIABLE & COMMENT LINES (FULL-WIDTH) ===== */
.tape-line.variable-line:not(.editing) .tape-op,
.tape-line.variable-line:not(.editing) .tape-value,
.tape-line.comment-line:not(.editing) .tape-op,
.tape-line.comment-line:not(.editing) .tape-value {
    display: none;
}

.tape-line.variable-line .tape-comment {
    color: var(--text-variable);
    font-weight: 600;
    font-family: var(--font-mono);
}

.tape-line.comment-line .tape-comment {
    color: var(--text-muted);
    font-style: italic;
}

/* ===== EMPTY SEPARATOR ===== */
.tape-line.separator-line {
    height: 18px;
    border: none;
    background: transparent;
}
.tape-line.separator-line:hover {
    background: transparent;
}

/* ===== EDIT MODE: when line is focused, show full-width input ===== */
.tape-line.editing .tape-op,
.tape-line.editing .tape-value,
.tape-line.editing .tape-comment {
    display: none;
}

.tape-line.editing .tape-input {
    position: static;
    width: auto;
    height: var(--line-h);
    opacity: 1;
    pointer-events: auto;
    padding-left: 12px;
}

/* ===== VARIABLES PANEL ===== */
.vars-panel {
    width: 240px;
    min-width: 240px;
    background: var(--bg-paper);
    border-left: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1), width 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    transform-origin: right;
    position: relative;
}

.vars-panel.resizing {
    transition: none !important;
}

.vars-panel.hidden {
    width: 0px !important;
    min-width: 0px !important;
    border-left: none !important;
    transform: scaleX(0);
}

.vars-resizer {
    position: absolute;
    left: 0;
    top: 0;
    bottom: 0;
    width: 6px;
    cursor: col-resize;
    background: transparent;
    transition: background 0.15s;
    z-index: 100;
}

.vars-resizer:hover,
.vars-resizer.dragging {
    background: var(--border-color-active);
}

.vars-header {
    padding: 14px 16px;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: var(--bg-tabs);
}

.vars-header h3 {
    font-size: 0.75rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--text-muted);
}

.btn-icon-sm {
    display: flex;
    align-items: center;
    justify-content: center;
    background: none;
    border: none;
    font-size: 1.3rem;
    cursor: pointer;
    color: var(--text-muted);
    padding: 0 4px;
    line-height: 1;
    transition: color 0.15s;
}

.btn-icon-sm:hover { color: var(--text-negative); }

.vars-list {
    list-style: none;
    padding: 8px;
    overflow-y: auto;
    flex: 1;
}

.var-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 8px 12px;
    font-family: var(--font-mono);
    font-size: 0.85rem;
    cursor: pointer;
    border-radius: 2px;
    margin-bottom: 4px;
    transition: all 0.15s;
    background: rgba(255, 255, 255, 0.005);
    border: 1px solid transparent;
    gap: 12px;
}

.var-item:hover {
    background: rgba(163, 230, 53, 0.02);
    border-color: rgba(163, 230, 53, 0.15);
}

.var-name {
    color: var(--text-variable);
    font-weight: 600;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    min-width: 0;
}

.var-value {
    color: var(--text-main);
    font-weight: 500;
    white-space: nowrap;
    flex-shrink: 0;
}

/* ===== STATUS BAR ===== */
.status-bar {
    height: 34px;
    min-height: 34px;
    background: var(--bg-tabs);
    border-top: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 16px;
    font-size: 0.75rem;
    color: var(--text-muted);
    font-family: var(--font-ui);
}

.status-actions { display: flex; gap: 8px; }

.status-btn {
    background: none;
    border: 1px solid var(--border-color);
    font-size: 0.75rem;
    color: var(--text-muted);
    cursor: pointer;
    padding: 3px 10px;
    border-radius: 2px;
    font-family: var(--font-ui);
    transition: all 0.15s;
}

.status-btn:hover {
    background: rgba(255, 255, 255, 0.03);
    color: var(--border-color-active);
    border-color: var(--border-color-active);
}

/* ===== SELECTION STYLES ===== */
.tape-line.selected {
    background: rgba(34, 211, 238, 0.06) !important;
    border-left-color: var(--text-variable);
}

/* ===== KEYPAD PANEL ===== */
.keypad-panel {
    width: 260px;
    min-width: 260px;
    background: var(--bg-paper);
    border-left: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1), width 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    transform-origin: right;
}

.keypad-panel.hidden {
    width: 0px !important;
    min-width: 0px !important;
    border-left: none !important;
    transform: scaleX(0);
}

.keypad-header {
    padding: 14px 16px;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: var(--bg-tabs);
}

.keypad-header h3 {
    font-size: 0.75rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--text-muted);
}

.keypad-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    grid-auto-rows: 44px;
    gap: 8px;
    padding: 16px;
    flex: 1;
    overflow-y: auto;
}

/* Keypad Buttons */
.keypad-btn {
    background: #1e2530; /* Azul-cinza escuro */
    border: 1px solid var(--border-color);
    border-radius: 4px;
    color: var(--border-color-active); /* Acid green / ciano */
    font-family: var(--font-ui);
    font-size: 0.95rem;
    font-weight: 700;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    user-select: none;
    transition: all 0.1s ease-in-out;
}

.keypad-btn:hover {
    background: #2d3748;
    border-color: var(--border-color-active);
}

.keypad-btn:active {
    transform: scale(0.96);
    background: #1a202c;
}

/* Number Buttons (7, 8, 9, etc.) */
.keypad-btn.btn-num {
    background: #16181f; /* Fundo de número sutil */
    color: var(--text-main); /* Off-white */
    font-weight: 500;
    font-size: 1.05rem;
}

.keypad-btn.btn-num:hover {
    background: #232733;
}

/* AC Button */
.keypad-btn.btn-orange {
    background: #7c2d12; /* Vermelho-laranja escuro */
    border-color: #9a3412;
    color: #ffedd5;
}

.keypad-btn.btn-orange:hover {
    background: #9a3412;
}

/* Backspace Button */
.keypad-btn.btn-blue {
    background: #334155;
    border-color: #475569;
    color: #e2e8f0;
}

.keypad-btn.btn-blue:hover {
    background: #475569;
}

/* Memory Buttons */
.keypad-btn.btn-mem {
    background: #111827;
    border-color: var(--border-color);
    color: var(--text-variable); /* Ciano */
    font-size: 0.85rem;
}

.keypad-btn.btn-mem:hover {
    background: #1f2937;
    border-color: var(--text-variable);
}

/* Plus Button (+) spans 2 rows */
.keypad-btn.btn-plus {
    grid-row: span 2;
    height: 100%;
    background: #1e293b;
    color: var(--border-color-active);
}

/* Equal Button (=) spans 2 rows */
.keypad-btn.btn-equal {
    grid-row: span 2;
    height: 100%;
    background: #0f172a;
    border-color: var(--border-color-active);
    color: var(--border-color-active);
}

.keypad-btn.btn-equal:hover {
    background: #1e293b;
}

/* Zero Button (0) spans 2 columns */
.keypad-btn.btn-zero {
    grid-column: span 2;
}

/* Tax Buttons span 2 columns each */
.keypad-btn.btn-tax {
    grid-column: span 2;
    background: #0f172a;
    border-color: var(--border-color);
    color: var(--text-comment); /* Verde sálvia */
    font-size: 0.85rem;
}

.keypad-btn.btn-tax:hover {
    background: #1e293b;
    border-color: var(--text-comment);
}

/* ===== FILE BUTTONS & COPY BUTTON ===== */
.tab-btn-file {
    display: flex;
    align-items: center;
    justify-content: center;
    background: none;
    border: none;
    border-left: 1px solid var(--border-color);
    padding: 0 14px;
    font-size: 1.1rem;
    cursor: pointer;
    color: var(--text-muted);
    transition: all 0.15s;
}

.tab-btn-file:hover {
    background: rgba(255, 255, 255, 0.02);
    color: var(--border-color-active);
}

.status-btn.btn-cyan {
    border-color: rgba(34, 211, 238, 0.3);
    color: var(--text-variable);
}

.status-btn.btn-cyan:hover {
    background: rgba(34, 211, 238, 0.05);
    border-color: var(--text-variable);
    color: var(--text-variable);
}

.status-btn.hidden-btn {
    display: none;
}