/* Variáveis de Cores Estilo Material Design */
:root {
    --primary: #2563eb;
    --primary-dark: #1e40af;
    --success: #16a34a;
    --danger: #dc2626;
    --bg: #f8fafc;
    --card: #ffffff;
    --text-main: #1e293b;
    --text-muted: #64748b;
    --border: #e2e8f0;
}

/* Reset e Base */
* {
    box-sizing: border-box;
    -webkit-tap-highlight-color: transparent;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background-color: var(--bg);
    color: var(--text-main);
    margin: 0;
    line-height: 1.5;
    display: flex;
    flex-direction: column;
    align-items: center;
}

/* Cabeçalho Fixo */
header {
    background: var(--primary);
    color: white;
    width: 100%;
    padding: 1rem;
    text-align: center;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    position: sticky;
    top: 0;
    z-index: 100;
}

header h1 {
    margin: 0;
    font-size: 1.25rem;
    letter-spacing: 0.5px;
}

/* Container Principal */
.container {
    width: 100%;
    max-width: 600px;
    padding: 15px;
    margin-bottom: 50px;
}

/* Cards */
.card {
    background: var(--card);
    border-radius: 16px;
    padding: 1.5rem;
    box-shadow: 0 4px 6px -1px rgba(0,0,0,0.05), 0 2px 4px -1px rgba(0,0,0,0.03);
    margin-bottom: 1.25rem;
    border: 1px solid var(--border);
}

/* Formulários e Seleção */
.setup-group {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 12px;
    margin-bottom: 1.25rem;
}

select {
    appearance: none;
    background-color: #fff;
    border: 1px solid var(--border);
    border-radius: 10px;
    padding: 12px;
    font-size: 15px;
    color: var(--text-main);
    cursor: pointer;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' fill='none' viewBox='0 0 24 24' stroke='%2364748b'%3E%3Cpath stroke-linecap='round' stroke-linejoin='round' stroke-width='2' d='M19 9l-7 7-7-7'%3E%3C/path%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 10px center;
    background-size: 18px;
}

/* Botão Gerar */
.btn-generate {
    background: var(--primary);
    color: white;
    border: none;
    padding: 15px;
    border-radius: 10px;
    font-size: 16px;
    font-weight: 700;
    width: 100%;
    cursor: pointer;
    transition: all 0.2s ease;
    box-shadow: 0 4px 12px rgba(37, 99, 235, 0.2);
}

.btn-generate:active {
    transform: scale(0.97);
    background: var(--primary-dark);
}

.btn-generate:disabled {
    background: #cbd5e1;
    box-shadow: none;
    cursor: not-allowed;
}

/* Questão e Alternativas */
.quest-text {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 1.5rem;
    color: #0f172a;
}

.option {
    display: block;
    width: 100%;
    padding: 16px;
    margin-bottom: 12px;
    border: 2px solid var(--border);
    border-radius: 12px;
    text-align: left;
    background: white;
    font-size: 15px;
    color: var(--text-main);
    cursor: pointer;
    transition: all 0.2s ease;
}

.option strong {
    color: var(--primary);
    margin-right: 8px;
}

.option:hover {
    border-color: var(--primary);
    background: #f0f7ff;
}

/* Estados da Resposta */
.correct {
    background: #f0fdf4 !important;
    border-color: var(--success) !important;
    color: #166534 !important;
}

.wrong {
    background: #fef2f2 !important;
    border-color: var(--danger) !important;
    color: #991b1b !important;
}

/* Feedback Box */
#feedback {
    margin-top: 1.5rem;
    padding: 1.25rem;
    border-radius: 12px;
    font-size: 14px;
    line-height: 1.6;
    border-left: 5px solid var(--primary);
    animation: fadeIn 0.4s ease-out;
}

/* Loading Spinner */
.loading {
    text-align: center;
    padding: 2rem;
}

.spinner {
    border: 4px solid rgba(0,0,0,0.05);
    border-left-color: var(--primary);
    border-radius: 50%;
    width: 40px;
    height: 40px;
    animation: spin 1s linear infinite;
    margin: 0 auto 15px;
}

@keyframes spin { to { transform: rotate(360deg); } }
@keyframes fadeIn { from { opacity: 0; transform: translateY(10px); } to { opacity: 1; transform: translateY(0); } }