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

html {
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    background-color: #f5f5f6;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
        Helvetica, Arial, sans-serif;
    color: #0f172a;
    padding: 24px;
}

body {
    width: 100%;
    max-width: 640px;
    border-radius: 12px;
    padding: 32px 28px;
    display: flex;
    flex-direction: column;
    gap: 16px;
}

body::before {
    content: "Simulador de Gramática Regular";
    display: block;
    font-size: 1.15rem;
    font-weight: 600;
    color: #0f172a;
    letter-spacing: -0.3px;
    padding-bottom: 12px;
    border-bottom: 1px solid #e2e8f0;
    margin-bottom: 4px;
    order: -2;
}

#voltar {
    order: -3;
    font-size: 0.85rem;
    color: #475569;
    text-decoration: none;
}

#voltar:hover {
    color: #0f172a;
}

.instrucoes {
    font-size: 0.85rem;
    color: #475569;
    line-height: 1.55;
}

code,
.mono,
input[type="text"],
textarea {
    font-family: ui-monospace, "Cascadia Code", "Consolas", "Liberation Mono",
        monospace;
}

input[type="text"],
textarea {
    width: 100%;
    padding: 10px 14px;
    background-color: #ffffff;
    border: 3px solid #cbd5e1;
    border-radius: 8px;
    color: #0f172a;
    font-size: 0.88rem;
    outline: none;
}

textarea {
    resize: vertical;
}

input[type="text"]:focus,
textarea:focus {
    border-color: #2563eb;
}

input[type="text"]::placeholder,
textarea::placeholder {
    color: #94a3b8;
    font-weight: 400;
}

/* Produções */
#gramatica {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.producao {
    display: flex;
    align-items: center;
    gap: 8px;
}

.producao .nt {
    width: 48px;
    flex: none;
    text-align: center;
}

.producao .nt[readonly] {
    background-color: #f1f5f9;
}

.regras {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 6px;
    flex: 1;
    min-width: 0;
}

.regras .regra {
    width: 96px;
    flex: 1 1 80px;
}

.seta,
.ou {
    color: #475569;
    font-weight: 500;
}

.invalida {
    border-color: #f13434ff !important;
}

.remover {
    padding: 6px 10px;
    flex: none;
}

#acoes {
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
}

button {
    padding: 10px 22px;
    background-color: #030509;
    border: none;
    border-radius: 8px;
    color: #ffffff;
    font-size: 0.9rem;
    font-weight: 500;
    cursor: pointer;
    white-space: nowrap;
}

button:hover {
    background-color: #1e293b;
}

button:active {
    background-color: #0f172a;
}

/* Saídas */
#saidaGramatica,
#resultados {
    font-size: 0.88rem;
    line-height: 1.55;
    padding: 12px 14px;
    border-radius: 8px;
    border: 1px solid #e2e8f0;
    background-color: #f8fafc;
    color: #475569;
    font-weight: 500;
    display: flex;
    flex-direction: column;
    gap: 6px;
}

#saidaGramatica:empty,
#resultados:empty {
    display: none;
}

.erro {
    color: #b91c1c;
}

.resultado summary {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 10px;
    cursor: pointer;
    list-style: none;
}

.resultado summary::-webkit-details-marker {
    display: none;
}

.resultado .palavra {
    color: #0f172a;
}

.badge {
    padding: 2px 10px;
    border-radius: 6px;
    color: #0f172a;
    font-size: 0.8rem;
}

.badge.aceita {
    background-color: #8ff152ff;
}

.badge.rejeitada {
    background-color: #f13434ff;
}

.derivacao {
    margin: 6px 0 4px;
    padding: 8px 12px;
    border-left: 2px solid #cbd5e1;
    color: #0f172a;
    white-space: pre-wrap;
}

.derivacao .regra-usada {
    color: #94a3b8;
}