:root {
    --bg-gradient: linear-gradient(135deg, #0f172a 0%, #1e293b 100%);
    --accent-color: #3b82f6;
    --accent-hover: #2563eb;
    --text-main: #f8fafc;
    --text-muted: #94a3b8;
    --glass-bg: rgba(30, 41, 59, 0.7);
    --glass-border: rgba(255, 255, 255, 0.05);
    /* Nové pomocné barvy pro stavy karet */
    --card-selected-border: #3b82f6;
    --card-selected-glow: rgba(59, 130, 246, 0.2);
    --success-color: #4ade80;
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
}

body {
    background: var(--bg-gradient);
    color: var(--text-main);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 20px;
    overflow-x: hidden;
}

.glow-bg {
    position: absolute;
    width: 400px;
    height: 400px;
    background: radial-gradient(circle, rgba(59, 130, 246, 0.15) 0%, rgba(0,0,0,0) 70%);
    top: 10%;
    left: 10%;
    z-index: 1;
    pointer-events: none;
}

.container {
    position: relative;
    z-index: 2;
    width: 100%;
    max-width: 900px;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 40px;
    align-items: center;
}

@media (max-width: 768px) {
    .container {
        grid-template-columns: 1fr;
        gap: 30px;
        text-align: center;
    }
}

.hero-text h1 {
    font-size: 3.5rem;
    font-weight: 800;
    line-height: 1.1;
    margin-bottom: 20px;
    letter-spacing: -0.05em;
    background: linear-gradient(to right, #fff, var(--text-muted));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.hero-text p {
    color: var(--text-muted);
    font-size: 1.1rem;
    margin-bottom: 30px;
}

.stats-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 15px;
}

/* 🔄 INOVACE: Interaktivní karta s plynulými přechody */
.stat-card {
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    backdrop-filter: blur(12px);
    padding: 20px; /* Mírně zvětšený vnitřní prostor */
    border-radius: 12px;
    cursor: pointer;
    user-select: none;
    position: relative;
    transition: border-color 0.25s ease, transform 0.2s cubic-bezier(0.4, 0, 0.2, 1), box-shadow 0.25s ease, background-color 0.25s ease;
}

/* 🔥 Moderní Hover efekt: Jemné vysunutí vzhůru a rozsvícení hran */
.stat-card:hover {
    transform: translateY(-4px);
    border-color: rgba(255, 255, 255, 0.15);
    background: rgba(30, 41, 59, 0.85);
    box-shadow: 0 12px 20px rgba(0, 0, 0, 0.2);
}

/* ⚡ Aktivní stisk: Mírné smáčknutí pro pocit fyzického kliku */
.stat-card:active {
    transform: translateY(-1px) scale(0.98);
}

/* 💎 PROFI STAV: Karta vybraná uživatelem (Aktivuje se přes JS třídu .selected) */
.stat-card.selected {
    border-color: var(--card-selected-border) !important;
    background: rgba(59, 130, 246, 0.05); /* Modravý nádech podkladu */
    box-shadow: 0 0 0 1px var(--card-selected-border), 0 10px 25px var(--card-selected-glow);
}

.stat-card span {
    display: block;
    color: var(--text-muted);
    font-size: 0.85rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    transition: color 0.25s ease;
}

/* Pokud je karta vybraná, podbarvíme horní štítek do akcentu */
.stat-card.selected span {
    color: var(--accent-color);
}

.stat-card strong {
    display: block;
    font-size: 1.4rem;
    color: #fff;
    margin-top: 5px;
}

/* 🧭 Nový vizuální indikátor stavu uvnitř karty */
.select-indicator {
    margin-top: 12px;
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--text-muted);
    display: flex;
    align-items: center;
    gap: 4px;
    transition: color 0.25s ease;
}

.stat-card:hover .select-indicator {
    color: #fff;
}

.stat-card.selected .select-indicator {
    color: var(--success-color);
}

/* Zbytek formulářových stylů zůstává beze změn */
.form-card {
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    backdrop-filter: blur(12px);
    padding: 40px;
    border-radius: 24px;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.3);
}

.form-card h2 {
    font-size: 1.6rem;
    font-weight: 700;
    margin-bottom: 5px;
}

.form-card .subtitle {
    color: var(--text-muted);
    font-size: 0.9rem;
    margin-bottom: 25px;
}

.input-group {
    margin-bottom: 20px;
    text-align: left;
}

.input-group label {
    display: block;
    font-size: 0.85rem;
    color: var(--text-muted);
    margin-bottom: 6px;
    font-weight: 500;
}

.input-group input {
    width: 100%;
    background: rgba(15, 23, 42, 0.6);
    border: 1px solid var(--glass-border);
    padding: 14px 16px;
    color: #fff;
    font-size: 1rem;
    border-radius: 10px;
    transition: all 0.2s ease;
}

.input-group input:focus {
    outline: none;
    border-color: var(--accent-color);
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.15);
}

button {
    width: 100%;
    background: var(--accent-color);
    color: #fff;
    border: none;
    padding: 16px;
    font-size: 1rem;
    font-weight: 600;
    border-radius: 10px;
    cursor: pointer;
    transition: background 0.2s ease, transform 0.1s ease;
    margin-top: 10px;
}

button:hover {
    background: var(--accent-hover);
}

button:active {
    transform: scale(0.98);
}

#responseMessage {
    margin-top: 15px;
    font-size: 0.95rem;
    text-align: center;
    min-height: 24px;
    font-weight: 500;
}

.loading-shimmer {
    animation: pulse 1.5s infinite ease-in-out;
}

@keyframes pulse {
    0%, 100% { opacity: 0.6; }
    50% { opacity: 1; }
}