:root {
    --bg-main: #f4f7f9;
    --sidebar-bg: #1b5e20;
    --sidebar-text: #ffffff;
    --card-bg: #ffffff;
    --text-main: #2c3e50;
    --text-muted: #7f8c8d;
    --accent-color: #2e7d32;
    --accent-hover: #4caf50;
    --border-color: #e0e0e0;
    --shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
    --radius: 12px;
}

[data-theme="dark"] {
    --bg-main: #121212;
    --sidebar-bg: #0d3311;
    --card-bg: #1e1e1e;
    --text-main: #e0e0e0;
    --text-muted: #a0a0a0;
    --border-color: #333333;
    --shadow: 0 4px 20px rgba(0, 0, 0, 0.5);
}

* { box-sizing: border-box; margin: 0; padding: 0; font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif; }

body { background-color: var(--bg-main); color: var(--text-main); transition: background 0.3s; }

.app-container { display: flex; height: 100vh; overflow: hidden; }

/* Sidebar */
.sidebar { width: 260px; background-color: var(--sidebar-bg); color: var(--sidebar-text); display: flex; flex-direction: column; transition: transform 0.3s ease; }
.brand { padding: 20px; display: flex; align-items: center; gap: 15px; border-bottom: 1px solid rgba(255,255,255,0.1); }
.brand h1 { font-size: 1.2rem; margin: 0; }
.brand span { font-size: 0.8rem; color: #a5d6a7; }
.logo-icon { font-size: 2rem; }

.nav-links { list-style: none; padding: 15px 0; overflow-y: auto; flex: 1; }
.nav-btn { width: 100%; text-align: left; background: none; border: none; padding: 15px 25px; color: rgba(255,255,255,0.7); font-size: 1rem; cursor: pointer; display: flex; align-items: center; gap: 15px; transition: 0.2s; }
.nav-btn:hover, .nav-btn.active { background-color: rgba(255,255,255,0.1); color: #fff; border-left: 4px solid #a5d6a7; }

/* Main Content */
.main-content { flex: 1; display: flex; flex-direction: column; overflow-y: auto; }
.topbar { display: flex; justify-content: space-between; align-items: center; padding: 20px 30px; background-color: var(--card-bg); border-bottom: 1px solid var(--border-color); }
.header-info h2 { font-size: 1.5rem; color: var(--accent-color); }
.slogan { font-size: 0.9rem; color: var(--text-muted); }
.menu-toggle { display: none; background: none; border: none; font-size: 1.5rem; cursor: pointer; color: var(--text-main); }
.action-btn { background: none; border: none; font-size: 1.5rem; cursor: pointer; color: var(--text-main); }

.content-area { padding: 30px; flex: 1; }
.module { display: none; animation: fadeIn 0.4s ease; }
.module.active { display: block; }
@keyframes fadeIn { from { opacity: 0; transform: translateY(10px); } to { opacity: 1; transform: translateY(0); } }

/* Cards & Forms */
.card { background-color: var(--card-bg); border-radius: var(--radius); padding: 30px; box-shadow: var(--shadow); max-width: 900px; margin: 0 auto 30px; }
.card h3 { color: var(--accent-color); margin-bottom: 10px; border-bottom: 2px solid var(--border-color); padding-bottom: 10px; }
.input-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); gap: 20px; margin: 20px 0; }
.form-group label { display: block; font-weight: 600; margin-bottom: 8px; font-size: 0.9rem; }
input, select, textarea { width: 100%; padding: 12px; border: 1px solid var(--border-color); border-radius: 8px; background-color: var(--bg-main); color: var(--text-main); font-size: 1rem; }
input:focus, select:focus, textarea:focus { outline: none; border-color: var(--accent-color); box-shadow: 0 0 5px rgba(46,125,50,0.3); }

/* Buttons */
.btn-primary { background-color: var(--accent-color); color: white; border: none; padding: 12px 25px; border-radius: 8px; cursor: pointer; font-size: 1rem; font-weight: 600; transition: 0.2s; }
.btn-primary:hover { background-color: var(--accent-hover); }
.btn-action { background-color: transparent; color: var(--accent-color); border: 1px solid var(--accent-color); padding: 8px 15px; border-radius: 5px; cursor: pointer; transition: 0.2s; }
.btn-action:hover { background-color: var(--accent-color); color: white; }
.flex-between { display: flex; justify-content: space-between; align-items: center; margin-bottom: 20px; }

/* Result Box */
.result-area { margin-top: 30px; padding-top: 20px; border-top: 1px dashed var(--border-color); }
.result-box { background-color: var(--bg-main); padding: 20px; border-radius: 8px; border-left: 5px solid var(--accent-color); margin-bottom: 20px; }
.result-box h4 { font-size: 1.4rem; color: var(--accent-color); margin-bottom: 10px; }

/* Calculadora Principal Grid */
.calc-card { max-width: 450px; padding: 20px; }
.calc-display-area { background-color: var(--bg-main); padding: 20px; border-radius: 10px; text-align: right; margin-bottom: 20px; border: 1px solid var(--border-color); position: relative; }
.calc-expression { font-size: 1rem; color: var(--text-muted); min-height: 20px; word-wrap: break-word; }
.calc-result { font-size: 2.5rem; font-weight: bold; color: var(--text-main); word-wrap: break-word; }
.calc-memory-indicator { position: absolute; top: 10px; left: 15px; font-size: 0.8rem; font-weight: bold; color: var(--accent-color); }
.calc-keypad { display: grid; grid-template-columns: repeat(5, 1fr); gap: 10px; }
.btn { padding: 15px 0; font-size: 1.1rem; border: none; border-radius: 8px; cursor: pointer; transition: 0.1s; background-color: var(--bg-main); color: var(--text-main); font-weight: 600; box-shadow: 0 2px 5px rgba(0,0,0,0.05); }
.btn:active { transform: scale(0.95); }
.btn.num { background-color: #fff; border: 1px solid var(--border-color); }
[data-theme="dark"] .btn.num { background-color: #2a2a2a; }
.btn.op { background-color: #e8f5e9; color: var(--accent-color); }
[data-theme="dark"] .btn.op { background-color: #1b5e20; color: #fff; }
.btn.fn { background-color: #f0f0f0; font-size: 0.95rem; }
[data-theme="dark"] .btn.fn { background-color: #333; }
.btn.action { background-color: #ffebee; color: #c62828; }
.btn.action.memory { background-color: #fff3e0; color: #ef6c00; font-size: 0.9rem; }
[data-theme="dark"] .btn.action.memory { background-color: #4e342e; color: #ffb74d; }
.btn.equals { background-color: var(--accent-color); color: white; grid-column: span 2; }
.btn.zero { grid-column: span 2; }

/* History */
.history-list { list-style: none; }
.history-item { padding: 15px; border-bottom: 1px solid var(--border-color); display: flex; justify-content: space-between; align-items: center; }
.history-item:last-child { border-bottom: none; }
.history-expr { font-size: 0.9rem; color: var(--text-muted); }
.history-res { font-size: 1.2rem; font-weight: bold; color: var(--accent-color); }
.history-meta { font-size: 0.8rem; color: var(--text-muted); display: block; margin-top: 5px; }

/* Footer */
.app-footer { text-align: center; padding: 20px; background-color: var(--card-bg); border-top: 1px solid var(--border-color); font-size: 0.85rem; color: var(--text-muted); }

/* Print */
@media print {
    .sidebar, .topbar, .btn, .calc-keypad, .app-footer, .input-grid { display: none !important; }
    .card { box-shadow: none; border: none; }
    .result-area { display: block !important; border: 2px solid #000; padding: 20px; }
}

/* Responsividade */
@media (max-width: 768px) {
    .sidebar { position: fixed; transform: translateX(-100%); z-index: 1000; height: 100vh; }
    .sidebar.open { transform: translateX(0); }
    .menu-toggle { display: block; }
    .calc-keypad { grid-template-columns: repeat(4, 1fr); }
    .btn.fn:nth-child(n+6):nth-child(-n+10) { display: none; } /* Oculta algumas fn em mobile */
}