:root {
    --primary: #c3f53c; /* Tennis neon green */
    --primary-hover: #b1e02a;
    --dark: #121417;
    --light-glass: rgba(255, 255, 255, 0.08);
    --border-glass: rgba(255, 255, 255, 0.15);
    --text-main: #f4f6fA;
    --text-muted: #abb1ba;
    --clay: #D9534F; 
}

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

body, html {
    font-family: 'Inter', sans-serif;
    background-color: var(--dark);
    color: var(--text-main);
    min-height: 100vh;
    overflow-x: hidden;
}

.background-container {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 0;
}

.bg-slide {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-size: cover;
    background-position: center;
    opacity: 0;
    transition: opacity 2s ease-in-out;
    transform: scale(1.05); /* Slight scale for visual depth */
}

.bg-slide.active {
    opacity: 1;
}

.overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(135deg, rgba(18, 20, 23, 0.7) 0%, rgba(18, 20, 23, 0.3) 100%);
    z-index: 1;
}

.logo-container {
    position: absolute;
    top: 25px;
    left: 25px;
    display: flex;
    align-items: center;
    gap: 12px;
    z-index: 10;
    animation: fadeIn 1s ease-out;
}

.logo-icon {
    width: 32px;
    height: 32px;
    filter: drop-shadow(0 0 8px rgba(195, 245, 60, 0.5));
}

.logo-text {
    font-family: 'Outfit', sans-serif;
    font-size: 1.5rem;
    font-weight: 700;
    color: white;
    letter-spacing: -0.5px;
    text-shadow: 0 2px 4px rgba(0,0,0,0.5);
}

.logo-text .highlight {
    color: var(--primary);
}

.card-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 15px;
    gap: 15px;
}

.language-selector {
    margin: 0;
}

.language-selector select {
    background: rgba(0, 0, 0, 0.5);
    color: white;
    border: 1px solid var(--border-glass);
    padding: 8px 16px;
    border-radius: 20px;
    font-family: 'Inter', sans-serif;
    font-size: 0.9rem;
    outline: none;
    cursor: pointer;
    backdrop-filter: blur(10px);
    transition: all 0.3s ease;
}

.language-selector select:hover {
    background: rgba(0, 0, 0, 0.8);
    border-color: var(--primary);
}

.main-container {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    padding: 40px 20px;
    position: relative;
    z-index: 10;
}

.glass-card {
    background: var(--light-glass);
    border: 1px solid var(--border-glass);
    border-radius: 24px;
    padding: 50px;
    max-width: 600px;
    width: 100%;
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
    animation: fadeIn 0.8s ease-out;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

h1 {
    font-family: 'Outfit', sans-serif;
    font-size: 3rem;
    font-weight: 700;
    margin-bottom: 0;
    color: var(--text-main);
    letter-spacing: -1px;
}

.subtitle {
    font-size: 1.1rem;
    color: var(--text-muted);
    margin-bottom: 35px;
    line-height: 1.6;
}

form {
    display: flex;
    flex-direction: column;
    gap: 24px;
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.form-group-row {
    display: flex;
    gap: 20px;
}

.half {
    flex: 1;
}

label {
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text-main);
}

input[type="text"],
input[type="email"],
select,
textarea {
    width: 100%;
    background: rgba(0, 0, 0, 0.3);
    border: 1px solid var(--border-glass);
    border-radius: 12px;
    padding: 14px 16px;
    color: var(--text-main);
    font-family: 'Inter', sans-serif;
    font-size: 1rem;
    transition: all 0.3s ease;
    outline: none;
}

input:focus,
select:focus,
textarea:focus {
    border-color: var(--primary);
    background: rgba(0, 0, 0, 0.5);
    box-shadow: 0 0 0 3px rgba(195, 245, 60, 0.1);
}

select option {
    background: var(--dark);
    color: white;
}

textarea {
    resize: vertical;
    min-height: 100px;
}

.radio-group {
    display: flex;
    gap: 20px;
    margin-top: 5px;
}

.radio-group label {
    display: flex;
    align-items: center;
    gap: 8px;
    cursor: pointer;
    font-weight: 400;
}

.radio-group input[type="radio"] {
    appearance: none;
    width: 20px;
    height: 20px;
    border: 2px solid var(--border-glass);
    border-radius: 50%;
    background: rgba(0,0,0,0.3);
    cursor: pointer;
    position: relative;
}

.radio-group input[type="radio"]:checked {
    border-color: var(--primary);
}

.radio-group input[type="radio"]:checked::after {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 10px;
    height: 10px;
    background: var(--primary);
    border-radius: 50%;
}

.checkbox-group {
    flex-direction: row;
    align-items: flex-start;
    gap: 12px;
    background: rgba(255, 255, 255, 0.03);
    padding: 16px;
    border-radius: 12px;
    border: 1px solid var(--border-glass);
}

.checkbox-group input[type="checkbox"] {
    margin-top: 4px;
    appearance: none;
    min-width: 20px;
    height: 20px;
    border: 2px solid var(--border-glass);
    border-radius: 6px;
    background: rgba(0,0,0,0.3);
    cursor: pointer;
    position: relative;
}

.checkbox-group input[type="checkbox"]:checked {
    background: var(--primary);
    border-color: var(--primary);
}

.checkbox-group input[type="checkbox"]:checked::after {
    content: '✓';
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    color: var(--dark);
    font-size: 14px;
    font-weight: bold;
}

.checkbox-group label {
    font-weight: 400;
    line-height: 1.5;
    font-size: 0.85rem;
    cursor: pointer;
}

button {
    background: var(--primary);
    color: var(--dark);
    border: none;
    border-radius: 12px;
    padding: 16px;
    font-family: 'Inter', sans-serif;
    font-size: 1.1rem;
    font-weight: 700;
    cursor: pointer;
    transition: all 0.3s ease;
    margin-top: 10px;
}

button:hover {
    background: var(--primary-hover);
    transform: translateY(-2px);
    box-shadow: 0 10px 20px rgba(195, 245, 60, 0.2);
}

button:active {
    transform: translateY(0);
}

@media (max-width: 768px) {
    .glass-card {
        padding: 30px 20px;
        border-radius: 20px;
    }

    h1 {
        font-size: 2.2rem;
    }
    
    /* Fix for overlapping header elements on phones */
    .logo-container {
        position: relative;
        top: 0;
        left: 0;
        justify-content: center;
        margin-top: 20px;
    }

    .card-header {
        flex-direction: column;
        justify-content: center;
        text-align: center;
    }

    .language-selector {
        margin: 10px auto 20px; 
        display: flex;
        justify-content: center;
    }

    /* Add space in case language selector or any element gets wrapped under the form */
    #tennis-form {
        margin-bottom: 20px; 
    }
}