:root {
    --primary: #4e6ef2;
    --dark: #1c1c1c;
    --light: #f5f5f5;
}

body {
    font-family: Arial, Helvetica, sans-serif;
    background: var(--light);
    margin: 0;
    color: var(--dark);
}

header {
    background: var(--primary);
    color: white;
    text-align: center;
    padding: 2rem 1rem;
}

header h1 {
    margin: 0;
    font-size: 2.5rem;
}

header p {
    font-size: 1.2rem;
    margin-top: 0.5rem;
}

main {
    max-width: 900px;
    margin: 2rem auto;
    padding: 0 1rem;
}

section {
    margin-bottom: 2rem;
}

section h2 {
    color: var(--primary);
    margin-bottom: 0.5rem;
}

/* Challenge Cards */
.challenge-card {
    background: white;
    border-left: 4px solid var(--primary);
    margin-bottom: 1rem;
    padding: 1rem;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
    cursor: pointer;
    transition: transform 0.2s, box-shadow 0.2s;
    overflow: hidden;
}

.challenge-card:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);
}

.challenge-card .details {
    display: none;
    margin-top: 0.5rem;
    color: #333;
}

.challenge-card.expanded .details {
    display: block;
}

/* How-to */
.how-to-timeline {
    display: flex;
    align-items: center;
    flex-direction: column;
    margin: 3rem auto 9rem auto;
    text-align: center;
    position: relative;
}

.how-to-timeline h2 {
    color: #7b5fff;
}

.timeline-wrapper {
    width: 1000px;
    position: relative;
}

.timeline-path {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 300px;
    pointer-events: none;
}

.steps {
    display: flex;
    justify-content: space-between;
    position: relative;
    margin-top: 40px;
}

.step {
    width: 180px;
    min-height: 240px;
    position: relative;
}

/* zigue-zague: pares mais abaixo */
.step:nth-child(even) {
    margin-top: 80px;
}

/* Flip Card Base */
.flip-card {
    background: transparent;
    width: 180px;
    height: 240px;
    perspective: 1000px;
}

.flip-card-inner {
    position: relative;
    width: 100%;
    height: 100%;
    text-align: center;
    transition: transform 0.8s;
    transform-style: preserve-3d;
}

.flip-card:hover .flip-card-inner {
    transform: rotateY(180deg);
}

/* Frente */
.flip-card-front,
.flip-card-back {
    position: absolute;
    width: 100%;
    height: 100%;
    backface-visibility: hidden;
    border-radius: 12px;
    background: #7b5fff;
    color: white;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    padding: 1rem;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);
}

.flip-card-text {
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 6px;
    height: 75%;
    color: #7b5fff;
    font-weight: 600;
    border-radius: 11px;
    background-color: white;
}

.flip-card-front img {
    width: 64px;
    height: 64px;
    margin-bottom: 1rem;
}

.flip-card-front h3 {
    margin: 0;
    font-size: 1.1rem;
}

/* Verso */
.flip-card-back {
    transform: rotateY(180deg);
    font-size: 0.95rem;
    padding: 1rem;
}

/* FAB */
.fab {
    position: fixed;
    bottom: 24px;
    right: 24px;
    width: 64px;
    height: 64px;
    background: var(--primary);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 2rem;
    text-decoration: none;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.3);
    transition: transform 0.2s;
}

.fab:hover {
    transform: scale(1.1);
}

footer {
    text-align: center;
    background: #e0e0e0;
    padding: 1rem;
    margin-top: 2rem;
    font-size: 0.9rem;
}