:root {
    --brand: #2563eb;
    --brand-dark: #1d4ed8;
    --bg-color: #f8fafc;
    --card-bg: #ffffff;
    --text-main: #0f172a;
    --text-muted: #64748b;
    --border-soft: #e2e8f0;
    --border-strong: #cbd5e1;
    --shadow-soft: 0 10px 30px rgba(15,23,42,.06);
    --shadow-hover: 0 20px 40px rgba(15,23,42,.08);
    --radius-xl: 0.75rem;
    --radius-2xl: 1rem;
    --font-sans: ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
}

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

body {
    font-family: var(--font-sans);
    background-color: var(--bg-color);
    color: var(--text-main);
    line-height: 1.5;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

a {
    text-decoration: none;
    color: inherit;
}

/* Header */
.site-header {
    background-color: var(--card-bg);
    border-bottom: 1px solid var(--border-soft);
    position: sticky;
    top: 0;
    z-index: 40;
}

.header-container {
    max-width: 80rem; /* 1280px */
    margin: 0 auto;
    padding: 1rem 1.5rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.logo {
    font-size: 1.25rem;
    font-weight: 600;
}

.logo span {
    color: var(--brand);
}

.tagline {
    font-size: 0.75rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.1em;
}
@media (max-width: 640px) {
    .tagline { display: none; }
}

/* Advertisement Wrappers */
.ad-wrapper {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    background-color: var(--card-bg);
    border-bottom: 1px solid var(--border-soft);
    padding: 1.5rem 0;
}

.ad-wrapper.inline-rectangle {
    border-top: 1px solid var(--border-soft);
    border-bottom: none;
    background-color: transparent;
    padding: 3rem 0;
}

.ad-label {
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--text-muted);
    margin-bottom: 0.5rem;
}

.ad-placeholder {
    display: flex;
    align-items: center;
    justify-content: center;
    background-color: var(--bg-color);
    border: 1px solid var(--border-strong);
    color: var(--text-muted);
    font-size: 0.875rem;
}

.leaderboard-top .ad-placeholder {
    width: 320px;
    height: 50px;
}
@media (min-width: 768px) {
    .leaderboard-top .ad-placeholder {
        width: 728px;
        height: 90px;
    }
}

.inline-rectangle .ad-placeholder {
    width: 300px;
    height: 250px;
}

/* Main Hub Content */
.hub-container {
    flex: 1;
    max-width: 80rem;
    margin: 0 auto;
    padding: 3rem 1.5rem;
    width: 100%;
}

.intro-section {
    text-align: center;
    margin-bottom: 3rem;
}

.intro-section h1 {
    font-size: 1.875rem;
    font-weight: 600;
    margin-bottom: 0.75rem;
}

@media (min-width: 640px) {
    .intro-section h1 {
        font-size: 2.25rem;
    }
}

.intro-section p {
    color: var(--text-muted);
    font-size: 1rem;
}

/* Tools Grid */
.tools-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 1.5rem;
}

@media (min-width: 768px) {
    .tools-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (min-width: 1024px) {
    .tools-grid {
        grid-template-columns: repeat(3, 1fr);
    }
}

.tool-card {
    background-color: var(--card-bg);
    border: 1px solid var(--border-soft);
    border-radius: var(--radius-2xl);
    padding: 1.5rem;
    box-shadow: var(--shadow-soft);
    display: flex;
    flex-direction: column;
    transition: transform 0.2s, box-shadow 0.2s, border-color 0.2s;
}

.tool-card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-hover);
    border-color: var(--border-strong);
}

.tool-card.planned {
    opacity: 0.65;
    pointer-events: none;
}

.card-icon {
    font-size: 2rem;
    margin-bottom: 1.25rem;
    background-color: var(--bg-color);
    width: 3.5rem;
    height: 3.5rem;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: var(--radius-xl);
    border: 1px solid var(--border-soft);
}

.tool-card h2 {
    font-size: 1.125rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
}

.tool-card p {
    color: var(--text-muted);
    font-size: 0.875rem;
    margin-bottom: 1.5rem;
    flex: 1;
}

.btn-launch {
    display: inline-block;
    background-color: var(--brand);
    color: #ffffff;
    padding: 0.75rem 1.25rem;
    border-radius: var(--radius-xl);
    font-size: 0.875rem;
    font-weight: 500;
    text-align: center;
    transition: background-color 0.2s, box-shadow 0.2s;
}

.tool-card:hover .btn-launch:not(.disabled) {
    background-color: var(--brand-dark);
}

.btn-launch:focus {
    outline: none;
    box-shadow: 0 0 0 3px rgba(37,99,235,.18);
}

.btn-launch.disabled {
    background-color: var(--bg-color);
    color: var(--text-muted);
    border: 1px solid var(--border-soft);
}

/* Footer */
.site-footer {
    background-color: var(--card-bg);
    border-top: 1px solid var(--border-soft);
    padding: 2rem 1.5rem;
}

.footer-links {
    display: flex;
    justify-content: center;
    gap: 1.5rem;
    flex-wrap: wrap;
    margin-bottom: 1rem;
}

.footer-links a {
    color: var(--text-muted);
    font-size: 0.875rem;
    transition: color 0.2s;
}

.footer-links a:hover {
    color: var(--text-main);
}

.copyright {
    color: var(--text-muted);
    font-size: 0.875rem;
    text-align: center;
}