:root {
    --md-sys-color-primary: #3553f1;
    --md-sys-color-on-primary: #ffffff;
    --md-sys-color-primary-container: #dbe3ff;
    --md-sys-color-on-primary-container: #001a5d;
    --md-sys-color-surface: #f8f9ff;
    --md-sys-color-on-surface: #1f2430;
    --md-sys-color-surface-variant: #e5e7f4;
    --md-sys-color-on-surface-variant: #50556a;
    --md-sys-color-outline: #7f85a0;
    --md-sys-elevation-shadow: 0 18px 40px rgba(53, 83, 241, 0.12);
}

* {
    box-sizing: border-box;
}

body {
    font-family: 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
    background: radial-gradient(circle at top left, rgba(53, 83, 241, 0.12), transparent 24%),
                radial-gradient(circle at bottom right, rgba(0, 86, 210, 0.10), transparent 18%),
                var(--md-sys-color-surface);
    color: var(--md-sys-color-on-surface);
    margin: 0;
    padding: 0;
    min-height: 100vh;
}

nav {
    background-color: rgba(255, 255, 255, 0.92);
    backdrop-filter: blur(16px);
    height: 80px;
    display: flex;
    justify-content: center;
    align-items: center;
    position: sticky;
    top: 0;
    z-index: 1000;
    box-shadow: 0 10px 36px rgba(16, 24, 40, 0.08);
}

.nav-container {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    width: min(100%, 960px);
    padding: 0 16px;
}

nav a {
    text-decoration: none;
    color: var(--md-sys-color-on-surface-variant);
    font-weight: 600;
    padding: 12px 24px;
    border-radius: 999px;
    transition: all 0.25s ease;
    font-size: 0.95rem;
}

nav a:hover {
    background-color: rgba(53, 83, 241, 0.08);
    color: var(--md-sys-color-primary);
}

nav a.active {
    background-color: var(--md-sys-color-primary-container);
    color: var(--md-sys-color-on-primary-container);
}

#content {
    display: grid;
    gap: 20px;
    max-width: 1040px;
    margin: 36px auto 48px;
    padding: 0 20px;
}

.source-card {
    display: block;
    width: 100%;
    text-align: left;
    padding: 24px;
    border-radius: 28px;
    border: 1px solid rgba(53, 83, 241, 0.12);
    background-color: #ffffff;
    color: var(--md-sys-color-on-surface);
    box-shadow: var(--md-sys-elevation-shadow);
    transition: transform 0.22s ease, box-shadow 0.22s ease, border-color 0.22s ease;
    cursor: pointer;
}

.source-card:hover {
    transform: translateY(-2px);
    box-shadow: 0 24px 56px rgba(53, 83, 241, 0.14);
    border-color: rgba(53, 83, 241, 0.18);
}

.source-card .nome {
    display: block;
    font-size: 1.35rem;
    font-weight: 700;
    margin-bottom: 10px;
    color: var(--md-sys-color-primary);
}

.source-card .messaggio {
    display: block;
    font-size: 1rem;
    line-height: 1.8;
    margin-bottom: 16px;
    color: var(--md-sys-color-on-surface);
}

.source-card .data {
    display: inline-flex;
    align-items: center;
    padding: 10px 14px;
    border-radius: 999px;
    background-color: var(--md-sys-color-primary-container);
    color: var(--md-sys-color-on-primary-container);
    font-size: 0.9rem;
    font-weight: 600;
}

@media (max-width: 720px) {
    nav {
        height: auto;
        padding: 16px 0;
    }
    .nav-container {
        justify-content: center;
    }
    .source-card {
        padding: 20px;
    }
    .source-card .nome {
        font-size: 1.2rem;
    }
}