:root {
            --bg-dark: #12121a;
            --panel-bg: #1e1e2d;
            --accent: #00e5ff;
            --accent-hover: #00b3cc;
            --carbon-color: #2b2b36;
            --hydrogen-color: #f0f4f8;
            --text-light: #e2e8f0;
            --danger: #ff4757;
            --success: #2ed573;
        }

        * {
            box-sizing: border-box;
            margin: 0;
            padding: 0;
            font-family: 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
            user-select: none;
        }

        body {
            background-color: var(--bg-dark);
            color: var(--text-light);
            display: flex;
            flex-direction: column;
            height: 100vh;
            overflow: hidden;
        }

        /* Cabeçalho */
        header {
            background: linear-gradient(135deg, #1a1a2e, #16213e);
            padding: 15px 30px;
            display: flex;
            align-items: center;
            box-shadow: 0 4px 15px rgba(0, 0, 0, 0.5);
            z-index: 20;
            border-bottom: 2px solid var(--accent);
        }

        .logo-placeholder {
            width: 60px;
            height: 60px;
            background-color: transparent;
            border-radius: 0;
            border: none;
            margin-right: 20px;
            display: flex;
            align-items: center;
            justify-content: center;
            object-fit: contain;
        }

        h1 {
            font-size: 1.8rem;
            font-weight: 700;
            letter-spacing: 1px;
            color: white;
            text-shadow: 0 0 10px rgba(0, 229, 255, 0.3);
        }

        h1 span {
            color: var(--accent);
            font-weight: 300;
            font-size: 1.2rem;
            display: block;
            margin-top: 5px;
        }

        /* Container Principal */
        #app-container {
            display: flex;
            flex: 1;
            overflow: hidden;
            position: relative;
        }

        /* Painéis Laterais */
        .sidebar-panel {
            width: 280px;
            background-color: var(--panel-bg);
            padding: 20px;
            display: flex;
            flex-direction: column;
            gap: 25px;
            box-shadow: 5px 0 20px rgba(0,0,0,0.5);
            z-index: 10;
        }

        #history-sidebar {
            width: 260px;
            box-shadow: -5px 0 20px rgba(0,0,0,0.5);
            border-left: 1px solid rgba(255,255,255,0.05);
        }

        .tool-section h3, .history-header h3 {
            font-size: 1.1rem;
            color: #8b9bb4;
            margin-bottom: 15px;
            text-transform: uppercase;
            letter-spacing: 1px;
            border-bottom: 1px solid rgba(255,255,255,0.1);
            padding-bottom: 8px;
        }

        /* Itens Arrastáveis e Ferramentas */
        .tool-item {
            background: rgba(255, 255, 255, 0.05);
            border: 2px solid rgba(255, 255, 255, 0.1);
            border-radius: 12px;
            padding: 15px;
            display: flex;
            align-items: center;
            gap: 15px;
            cursor: grab;
            transition: all 0.3s ease;
        }

        .tool-item:hover {
            background: rgba(255, 255, 255, 0.1);
            border-color: var(--accent);
            transform: translateY(-2px);
        }

        .tool-item:active { cursor: grabbing; }
        .tool-item.bond-tool { cursor: pointer; }

        .tool-item.bond-tool.active {
            background: rgba(0, 229, 255, 0.15);
            border-color: var(--accent);
            box-shadow: 0 0 15px rgba(0, 229, 255, 0.3);
        }

        .tool-icon {
            width: 40px;
            height: 40px;
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            font-weight: bold;
            font-size: 1.2rem;
            box-shadow: inset -3px -3px 8px rgba(0,0,0,0.5), inset 3px 3px 8px rgba(255,255,255,0.2);
        }

        .icon-c { background: var(--carbon-color); color: var(--accent); border: 2px solid #555; }
        .icon-h { background: var(--hydrogen-color); color: #333; border: 2px solid #ccc; }
        
        .bond-icon-container {
            width: 40px;
            height: 40px;
            display: flex;
            flex-direction: column;
            justify-content: center;
            align-items: center;
            gap: 4px;
        }
        
        .bond-line-icon {
            width: 30px;
            height: 3px;
            background-color: var(--text-light);
            border-radius: 2px;
        }

        /* Histórico (Painel Direito) */
        #history-list {
            list-style: none;
            flex: 1;
            overflow-y: auto;
            display: flex;
            flex-direction: column;
            gap: 10px;
        }

        #history-list li {
            background: rgba(255, 255, 255, 0.03);
            padding: 12px 15px;
            border-radius: 8px;
            font-size: 1rem;
            border-left: 3px solid var(--success);
            animation: fadeIn 0.4s ease-out;
            display: flex;
            align-items: center;
        }

        #history-list li span.num {
            color: #8b9bb4;
            font-weight: bold;
            margin-right: 10px;
            font-size: 0.9rem;
        }

        .history-item-link {
            all: unset;
            cursor: pointer;
            width: 100%;
            display: flex;
            align-items: center;
            color: inherit;
        }

        .history-item-link:hover strong {
            color: var(--accent);
            text-decoration: underline;
        }

        .btn-discreet {
            background: none;
            border: none;
            color: #6c7a92;
            font-size: 0.85rem;
            cursor: pointer;
            text-align: center;
            padding: 10px;
            margin-top: auto;
            transition: color 0.3s;
            text-decoration: underline;
        }

        .btn-discreet:hover {
            color: var(--danger);
        }

        @keyframes fadeIn {
            from { opacity: 0; transform: translateX(10px); }
            to { opacity: 1; transform: translateX(0); }
        }

        /* Laboratório (Área Principal) */
        #lab-area {
            flex: 1;
            position: relative;
            background: radial-gradient(circle at center, #1a1a24 0%, #12121a 100%);
            overflow: hidden;
        }

        #grid-bg {
            position: absolute;
            width: 100%;
            height: 100%;
            background: linear-gradient(180deg, rgba(14, 52, 72, 0.5), rgba(5, 18, 28, 0.88));
            z-index: 1;
        }

        /* Container da Molécula (DOM 2D) */
        #molecule-container {
            position: absolute;
            top: 0; left: 0; right: 0; bottom: 0;
            z-index: 5;
            transition: opacity 0.4s ease-in-out;
        }

        #bonds-svg {
            position: absolute;
            top: 0; left: 0; width: 100%; height: 100%;
            pointer-events: none;
        }

        .bond-svg-line {
            stroke: #8b9bb4;
            stroke-linecap: round;
            pointer-events: stroke;
            cursor: pointer;
            transition: stroke 0.2s;
        }
        
        .bond-svg-line:hover { stroke: var(--danger); }

        /* Átomos na Tela */
        .atom-node {
            position: absolute;
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            font-weight: bold;
            font-size: 1.4rem;
            cursor: pointer;
            transform: translate(-50%, -50%);
            box-shadow: 0 5px 15px rgba(0,0,0,0.6), inset -4px -4px 10px rgba(0,0,0,0.5), inset 4px 4px 10px rgba(255,255,255,0.2);
            transition: transform 0.1s, box-shadow 0.2s;
        }

        .atom-node:active {
            cursor: grabbing;
            transform: translate(-50%, -50%) scale(1.1);
        }

        .atom-node.node-c {
            width: 60px;
            height: 60px;
            background: radial-gradient(circle at 30% 30%, #4a4a5a, #111116);
            color: var(--accent);
            border: 2px solid #555;
        }

        .atom-node.node-h {
            width: 45px;
            height: 45px;
            background: radial-gradient(circle at 30% 30%, #ffffff, #b0bec5);
            color: #1a1a2e;
            border: 2px solid #ccc;
        }

        /* Efeito de Erro e Destaque */
        .error-pulse {
            animation: pulse-red 1s infinite alternate;
            box-shadow: 0 0 20px var(--danger), inset 0 0 10px var(--danger);
            border-color: var(--danger) !important;
        }

        @keyframes pulse-red {
            from { box-shadow: 0 0 10px var(--danger); }
            to { box-shadow: 0 0 40px var(--danger); }
        }

        /* Controles Inferiores */
        .controls {
            position: absolute;
            bottom: 40px; 
            left: 50%;
            transform: translateX(-50%);
            z-index: 20;
            display: flex;
            gap: 20px;
            background: rgba(30, 30, 45, 0.85);
            padding: 15px 30px;
            border-radius: 30px;
            backdrop-filter: blur(10px);
            border: 1px solid rgba(255,255,255,0.1);
            box-shadow: 0 10px 30px rgba(0,0,0,0.5);
        }

        .btn {
            padding: 12px 25px;
            border: none;
            border-radius: 20px;
            font-size: 1.1rem;
            font-weight: 600;
            cursor: pointer;
            transition: all 0.3s;
            display: flex;
            align-items: center;
            gap: 10px;
        }

        .btn-check {
            background: linear-gradient(45deg, var(--accent), #0099ff);
            color: #12121a;
            box-shadow: 0 4px 15px rgba(0, 229, 255, 0.4);
        }

        .btn-check:hover {
            transform: translateY(-2px);
            box-shadow: 0 6px 20px rgba(0, 229, 255, 0.6);
        }

        .btn-clear {
            background: rgba(255, 71, 87, 0.1);
            color: var(--danger);
            border: 1px solid var(--danger);
        }

        .btn-clear:hover {
            background: var(--danger);
            color: white;
            transform: translateY(-2px);
        }

        /* Copyright Footer */
        .copyright {
            position: absolute;
            bottom: 8px;
            left: 50%;
            transform: translateX(-50%);
            font-size: 0.85rem;
            color: #ffffff;
            z-index: 10;
            text-align: center;
        }

        .copyright a {
            color: var(--accent);
            text-decoration: none;
            transition: color 0.3s;
        }

        .copyright a:hover {
            color: #ffffff;
            text-decoration: underline;
        }

        /* Overlay de Mensagens (HUD) */
        #hud-message {
            position: absolute;
            top: 30px;
            left: 50%;
            transform: translateX(-50%) translateY(-20px);
            background: rgba(0, 0, 0, 0.85);
            padding: 15px 40px;
            border-radius: 30px;
            font-size: 1.3rem;
            font-weight: bold;
            text-align: center;
            opacity: 0;
            visibility: hidden;
            transition: all 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
            z-index: 30;
            border: 2px solid transparent;
            box-shadow: 0 10px 30px rgba(0,0,0,0.5);
            line-height: 1.4;
        }

        #hud-message.show {
            opacity: 1;
            visibility: visible;
            transform: translateX(-50%) translateY(0);
        }

        #hud-message.success {
            background: rgba(15, 35, 25, 0.95);
            color: var(--success);
            border-color: var(--success);
            text-shadow: 0 0 10px rgba(46, 213, 115, 0.5);
            font-size: 1.6rem;
            padding: 20px 50px;
            box-shadow: 0 10px 40px rgba(46, 213, 115, 0.3);
        }

        #hud-message.error {
            color: var(--danger);
            border-color: var(--danger);
            text-shadow: 0 0 10px rgba(255, 71, 87, 0.5);
        }

        #explosion-canvas {
            position: absolute;
            top: 0; left: 0; width: 100%; height: 100%;
            pointer-events: none;
            z-index: 25;
        }

        #tool-eraser.active {
            background: rgba(255, 71, 87, 0.15);
            border-color: var(--danger);
            color: var(--danger);
        }

        :root {
            --bg-dark: #071724;
            --panel-bg: rgba(10, 31, 44, 0.78);
            --accent: #19e6b2;
            --accent-hover: #00b890;
            --carbon-color: #313a4a;
            --hydrogen-color: #f1f5fa;
            --text-light: #eff8ff;
            --danger: #ff4f6f;
            --success: #62f58e;
            --line-soft: rgba(201, 230, 245, 0.22);
        }

        * {
            font-family: 'Space Grotesk', 'Segoe UI', sans-serif;
        }

        * {
            scrollbar-width: thin;
            scrollbar-color: rgba(27, 230, 178, 0.75) rgba(7, 24, 36, 0.9);
        }

        ::-webkit-scrollbar {
            width: 10px;
            height: 10px;
        }

        ::-webkit-scrollbar-track {
            background: rgba(7, 24, 36, 0.9);
            border-radius: 10px;
        }

        ::-webkit-scrollbar-thumb {
            background: linear-gradient(180deg, rgba(27, 230, 178, 0.9), rgba(49, 184, 255, 0.85));
            border-radius: 10px;
            border: 2px solid rgba(7, 24, 36, 0.9);
        }

        ::-webkit-scrollbar-thumb:hover {
            background: linear-gradient(180deg, rgba(44, 242, 194, 1), rgba(78, 201, 255, 1));
        }

        body {
            min-height: 100vh;
            height: 100vh;
            background:
                radial-gradient(circle at 8% 4%, rgba(255, 170, 30, 0.24), transparent 34%),
                radial-gradient(circle at 92% 14%, rgba(49, 184, 255, 0.25), transparent 33%),
                linear-gradient(130deg, #06141f 0%, #0b3f47 100%);
            overflow: hidden;
            position: relative;
        }

        body::before {
            content: "";
            position: fixed;
            inset: 0;
            pointer-events: none;
            background:
                linear-gradient(90deg, rgba(255,255,255,0.03) 1px, transparent 1px) 0 0/56px 56px,
                linear-gradient(rgba(255,255,255,0.03) 1px, transparent 1px) 0 0/56px 56px;
            opacity: 0.18;
        }

        header {
            margin: 10px 12px 0;
            padding: 9px 12px;
            border-radius: 16px;
            border-bottom: 1px solid var(--line-soft);
            background: linear-gradient(132deg, rgba(8, 39, 53, 0.95), rgba(18, 27, 56, 0.84));
            box-shadow: 0 12px 28px rgba(0,0,0,0.32);
            justify-content: space-between;
            gap: 10px;
        }

        .logo-placeholder {
            width: 46px;
            height: 46px;
            border-radius: 12px;
            border: 2px solid rgba(255,255,255,0.32);
            object-fit: cover;
            margin-right: 0;
            box-shadow: 0 10px 20px rgba(0,0,0,0.28);
            flex-shrink: 0;
        }

        .logo-fallback {
            display: none;
            width: 46px;
            height: 46px;
            border-radius: 12px;
            border: 2px dashed rgba(255,255,255,0.36);
            font-size: 9px;
            font-weight: 700;
            color: #c5dff1;
            align-items: center;
            justify-content: center;
            text-align: center;
            line-height: 1.1;
            flex-shrink: 0;
        }

        .brand-wrap {
            display: flex;
            align-items: center;
            gap: 10px;
            min-width: 0;
            flex: 1;
        }

        .brand-text {
            min-width: 0;
        }

        h1 {
            font-family: 'Baloo 2', 'Trebuchet MS', sans-serif;
            font-size: 1.6rem;
            letter-spacing: 0.2px;
            text-shadow: 0 0 18px rgba(0, 229, 255, 0.25);
            line-height: 1;
        }

        .brand-subtitle {
            display: block;
            font-size: 0.72rem;
            color: #c9dfec;
            margin-top: 2px;
            letter-spacing: 0.1px;
        }

        #app-container {
            display: grid;
            grid-template-columns: minmax(240px, 300px) minmax(0, 1fr) minmax(220px, 280px);
            gap: 14px;
            padding: 10px 12px 12px;
            overflow: hidden;
            min-height: 0;
            align-items: stretch;
        }

        .sidebar-panel {
            width: auto;
            border-radius: 20px;
            border: 1px solid var(--line-soft);
            background-color: var(--panel-bg);
            box-shadow: 0 16px 28px rgba(0,0,0,0.25);
            backdrop-filter: blur(10px);
            gap: 18px;
            padding: 18px;
            min-height: 0;
            overflow: auto;
        }

        #history-sidebar {
            width: auto;
            border-left: 1px solid var(--line-soft);
            box-shadow: 0 16px 28px rgba(0,0,0,0.22);
        }

        .tool-list {
            display: grid;
            gap: 10px;
        }

        .tool-item {
            border: 1px solid rgba(255,255,255,0.2);
            border-radius: 14px;
            padding: 12px;
            min-height: 66px;
            background: rgba(8, 21, 32, 0.58);
            transition: transform 0.25s ease, border-color 0.25s ease, box-shadow 0.25s ease;
        }

        .tool-item:hover {
            border-color: rgba(25, 230, 178, 0.76);
            box-shadow: 0 10px 20px rgba(0,0,0,0.28);
        }

        .tool-item.bond-tool.active {
            background: linear-gradient(132deg, rgba(25, 230, 178, 0.22), rgba(49, 184, 255, 0.22));
            box-shadow: 0 10px 22px rgba(0,0,0,0.3);
            border-color: rgba(25, 230, 178, 0.9);
        }

        .tool-meta {
            display: flex;
            flex-direction: column;
            gap: 3px;
        }

        .tool-meta small {
            color: #b7cfde;
            font-size: 0.75rem;
        }

        .tool-section-last {
            margin-top: auto;
        }

        #lab-area {
            border-radius: 22px;
            border: 1px solid var(--line-soft);
            box-shadow: 0 18px 34px rgba(0,0,0,0.34);
            min-height: 0;
            background:
                radial-gradient(circle at 50% 12%, rgba(162, 243, 255, 0.34), transparent 56%),
                linear-gradient(180deg, rgba(36, 104, 133, 0.9) 0%, rgba(20, 66, 92, 0.94) 100%);
            isolation: isolate;
        }

        #grid-bg {
            overflow: hidden;
            background:
                radial-gradient(circle at 50% 50%, rgba(120, 220, 255, 0.22), transparent 58%),
                linear-gradient(145deg, rgba(58, 146, 181, 0.5), rgba(27, 88, 120, 0.82));
        }

        #grid-bg::before {
            content: "";
            position: absolute;
            inset: 0;
            background:
                linear-gradient(90deg, rgba(224, 249, 255, 0.28) 1px, transparent 1px) center/42px 42px,
                linear-gradient(0deg, rgba(224, 249, 255, 0.28) 1px, transparent 1px) center/42px 42px;
            box-shadow: inset 0 0 70px rgba(12, 46, 66, 0.5);
            z-index: 1;
        }

        #grid-bg::after {
            content: "";
            position: absolute;
            inset: -30% -30%;
            background:
                conic-gradient(from 0deg, rgba(25, 190, 255, 0.2), transparent 30%, rgba(25, 190, 255, 0.16), transparent 60%, rgba(25, 190, 255, 0.2)),
                radial-gradient(circle at center, rgba(108, 252, 206, 0.12), transparent 58%);
            opacity: 0.55;
            z-index: 2;
            pointer-events: none;
        }

        #lab-area::before,
        #lab-area::after {
            content: none;
        }

        .lab-decor {
            position: absolute;
            right: 0;
            bottom: 0;
            height: 66%;
            max-height: 66%;
            width: auto;
            display: block;
            object-fit: contain;
            pointer-events: none;
            user-select: none;
            z-index: 8;
            opacity: 0.95;
            filter: none;
        }

        .controls {
            bottom: 18px;
            width: min(92%, 560px);
            display: grid;
            grid-template-columns: repeat(2, minmax(0, 1fr));
            gap: 10px;
            padding: 12px;
            border-radius: 20px;
            background: rgba(5, 21, 31, 0.82);
            border: 1px solid rgba(255,255,255,0.2);
        }

        .btn {
            width: 100%;
            justify-content: center;
            border-radius: 14px;
            padding: 12px 14px;
            font-size: 1rem;
        }

        .btn-check {
            background: linear-gradient(135deg, #1be6b2, #7aff8e);
            color: #06212d;
        }

        .btn-clear {
            background: linear-gradient(135deg, #ff4f6f, #ff9050);
            color: #ffffff;
            border: none;
        }

        .copyright {
            left: 50%;
            transform: translateX(-50%);
            right: auto;
            top: auto;
            bottom: 8px;
            background: rgba(7, 23, 35, 0.58);
            border: 1px solid rgba(255,255,255,0.16);
            border-radius: 10px;
            padding: 5px 8px;
            font-size: 0.74rem;
        }

        .copyright-header {
            position: absolute;
            left: 50%;
            right: auto;
            top: auto;
            bottom: 6px;
            transform: translateX(-50%);
            margin: 0;
            padding: 0;
            border: none;
            background: transparent;
            font-size: 0.55rem;
            line-height: 1;
            color: rgba(214, 238, 248, 0.78);
            white-space: nowrap;
            z-index: 30;
        }

        #hud-message {
            top: 20px;
            width: min(90%, 760px);
            border-radius: 20px;
            font-size: 1.18rem;
        }

        @media (max-width: 1320px) {
            #app-container {
                grid-template-columns: minmax(220px, 270px) minmax(0, 1fr);
                grid-template-areas:
                    "tools lab"
                    "history lab";
            }

            #sidebar { grid-area: tools; }
            #history-sidebar { grid-area: history; }
            #lab-area { grid-area: lab; }
        }

        @media (max-width: 980px) {
            body { overflow: auto; }

            header {
                margin: 8px 10px 0;
                padding: 8px 10px;
            }

            #app-container {
                grid-template-columns: 1fr;
                grid-template-areas: "tools" "lab" "history";
                overflow: visible;
                padding: 12px;
            }

            .logo-placeholder,
            .logo-fallback {
                width: 42px;
                height: 42px;
            }

            h1 { font-size: 1.35rem; }
            .brand-subtitle { font-size: 0.66rem; }

            #lab-area { min-height: 520px; }

            .controls {
                position: static;
                transform: none;
                margin: 14px auto 12px;
                width: min(94%, 560px);
            }

        }

        @media (max-width: 700px) {
            h1 { font-size: 1.2rem; }
            .controls { grid-template-columns: 1fr; }
            #hud-message { font-size: 1.02rem; padding: 12px 18px; }
            #lab-area { min-height: 470px; }
            .lab-decor { height: 52%; max-height: 52%; right: 0; bottom: 0; }
        }