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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #1a1a1a 0%, #0d1b2a 100%);
    min-height: 100vh;
    padding: 40px 20px;
}

.container {
    max-width: 1400px;
    margin: 0 auto;
}

h1 {
    color: #fff;
    text-align: center;
    margin-bottom: 40px;
    font-size: 2.5em;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.5);
}

.grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    gap: 15px;
    padding: 20px;
}

.card {
    width: 250px;
    height: 250px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    border-radius: 15px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.5);
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    overflow: hidden;
    justify-self: center;
}

.card:hover {
    transform: translateY(-10px) scale(1.05);
    box-shadow: 0 15px 40px rgba(0,0,0,0.7);
}

.card h2 {
    color: #fff;
    font-size: 1.8em;
    text-align: center;
    padding: 20px;
    z-index: 2;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.5);
}

.card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0,0,0,0.2);
    transition: all 0.3s ease;
}

.card:hover::before {
    background: rgba(0,0,0,0.1);
}

/* Cores diferentes para cada card */
.card:nth-child(1) { background: linear-gradient(135deg, #667eea 0%, #764ba2 100%); }
.card:nth-child(2) { background: linear-gradient(135deg, #f093fb 0%, #f5576c 100%); }
.card:nth-child(3) { background: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%); }
.card:nth-child(4) { background: linear-gradient(135deg, #43e97b 0%, #38f9d7 100%); }
.card:nth-child(5) { background: linear-gradient(135deg, #fa709a 0%, #fee140 100%); }
.card:nth-child(6) { background: linear-gradient(135deg, #30cfd0 0%, #330867 100%); }
.card:nth-child(7) { background: linear-gradient(135deg, #a8edea 0%, #fed6e3 100%); }
.card:nth-child(8) { background: linear-gradient(135deg, #ff9a9e 0%, #fecfef 100%); }
.card:nth-child(9) { background: linear-gradient(135deg, #ffecd2 0%, #fcb69f 100%); }
.card:nth-child(10) { background: linear-gradient(135deg, #ff6e7f 0%, #bfe9ff 100%); }
.card:nth-child(11) { background: linear-gradient(135deg, #e0c3fc 0%, #8ec5fc 100%); }
.card:nth-child(12) { background: linear-gradient(135deg, #f77062 0%, #fe5196 100%); }

/* Modal para exibir PDFs */
.modal {
    display: none;
    position: fixed;
    z-index: 1000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0,0,0,0.9);
    overflow: auto;
}

.modal-content {
    background-color: #2a2a2a;
    margin: 2% auto;
    padding: 30px;
    border-radius: 15px;
    width: 90%;
    max-width: 1200px;
    max-height: 85vh;
    overflow-y: auto;
    position: relative;
}

.close {
    color: #aaa;
    float: right;
    font-size: 35px;
    font-weight: bold;
    cursor: pointer;
    line-height: 20px;
}

.close:hover,
.close:focus {
    color: #fff;
}

.modal h2 {
    color: #fff;
    margin-bottom: 20px;
    padding-bottom: 15px;
    border-bottom: 2px solid #667eea;
}

.pdf-list {
    list-style: none;
    padding: 0;
}

.pdf-list li {
    background: #3a3a3a;
    margin: 10px 0;
    padding: 15px 20px;
    border-radius: 8px;
    transition: all 0.3s ease;
}

.pdf-list li:hover {
    background: #4a4a4a;
    transform: translateX(10px);
}

.pdf-list a {
    color: #4facfe;
    text-decoration: none;
    font-size: 1.1em;
    display: block;
}

.pdf-list a:hover {
    color: #00f2fe;
}

.empty-message {
    color: #aaa;
    font-style: italic;
    text-align: center;
    padding: 20px;
}

.contribute-btn {
    display: inline-block;
    margin: 15px 10px 15px 0;
    padding: 12px 24px;
    background: #0d1b2a;
    color: white;
    border-radius: 8px;
    text-decoration: none;
    font-size: 16px;
    transition: all 0.3s ease;
    box-shadow: 0 4px 15px rgba(0,0,0,0.3);
}

.contribute-btn:hover {
    background: #1a3a52;
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(0,0,0,0.4);
}

.view-mode-btn {
    display: inline-block;
    margin: 15px 0;
    padding: 12px 24px;
    background: #667eea;
    color: white;
    border-radius: 8px;
    text-decoration: none;
    font-size: 16px;
    text-align: center;
    transition: all 0.3s ease;
    box-shadow: 0 4px 15px rgba(0,0,0,0.3);
}

.view-mode-btn:hover {
    background: #764ba2;
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(0,0,0,0.4);
}

.button-container {
    text-align: center;
    margin-bottom: 30px;
}