:root {
    --primary-bg: #f8fafc;
    --secondary-bg: #ffffff;
    --primary-text: #0f172a;
    --secondary-text: #475569;
    --accent-color: #4f46e5;
    --accent-hover: #4338ca;
    --border-color: #e2e8f0;
    --box-shadow: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    --rounded-lg: 0.75rem;
    --transition-duration: 0.3s;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Poppins', sans-serif;
    background-color: var(--primary-bg);
    color: var(--primary-text);
    line-height: 1.7;
    overflow-x: hidden;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

.container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 20px;
}

main {
    flex-grow: 1;
}


.header {
    background-color: var(--secondary-bg);
    padding: 1rem 0;
    position: sticky;
    top: 0;
    z-index: 1000;
    box-shadow: 0 2px 4px rgba(0,0,0,0.05);
    border-bottom: 1px solid var(--border-color);
}

.navbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.navbar .nav-links {
    display: flex;
    gap: 1.5rem;
}

.navbar .nav-links a {
    color: var(--primary-text);
    text-decoration: none;
    font-weight: 500;
    position: relative;
    padding-bottom: 5px;
}

.navbar .nav-links a::after {
    content: '';
    position: absolute;
    width: 0;
    height: 2px;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    background-color: var(--accent-color);
    transition: width var(--transition-duration) ease;
}

.navbar .nav-links a:hover::after {
    width: 100%;
}


.section {
    padding: 80px 0;
    display: flex;
    align-items: center;
    justify-content: center;
}

.section .container {
    width: 100%;
}

.section-title {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: 1rem;
    font-weight: 700;
}

.section-subtitle {
    text-align: center;
    font-size: 1.1rem;
    color: var(--secondary-text);
    margin-bottom: 3rem;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}


.btn {
    display: inline-block;
    background-color: var(--accent-color);
    color: #fff;
    padding: 14px 28px;
    border-radius: var(--rounded-lg);
    text-decoration: none;
    font-size: 1rem;
    font-weight: 600;
    transition: background-color var(--transition-duration) ease, transform 0.2s ease;
    border: none;
    cursor: pointer;
    text-align: center;
}

.btn:hover {
    background-color: var(--accent-hover);
    transform: translateY(-3px);
}


.footer {
    background-color: #0f172a;
    color: #94a3b8;
    text-align: center;
    padding: 2rem 0;
    margin-top: auto;
}


.form-card {
    background-color: var(--secondary-bg);
    padding: 2.5rem;
    border-radius: var(--rounded-lg);
    box-shadow: var(--box-shadow);
    border: 1px solid var(--border-color);
    max-width: 700px;
    margin: 0 auto;
    width: 100%;
}

.form-header .section-title {
    margin-bottom: 0.5rem;
}

.form-header .section-subtitle {
    margin-bottom: 2rem;
}

.form-group {
    margin-bottom: 1.5rem;
}

label {
    display: block;
    font-weight: 600;
    color: var(--primary-text);
    margin-bottom: 8px;
    font-size: 0.9rem;
}

input[type="text"],
input[type="tel"],
input[type="number"], 
input[type="email"],
textarea,
select {
    width: 100%;
    padding: 12px;
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    box-sizing: border-box;
    font-family: 'Poppins', sans-serif;
    font-size: 1rem;
    background-color: var(--primary-bg);
    color: var(--primary-text);
    transition: border-color 0.3s, box-shadow 0.3s;
}

input::placeholder, textarea::placeholder {
    color: #94a3b8;
}

input[type="text"]:focus,
input[type="tel"]:focus,
input[type="number"]:focus,
input[type="email"]:focus,
textarea:focus,
select:focus {
    outline: none;
    border-color: var(--accent-color);
    box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.15);
}

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

.submit-btn {
    width: 100%;
    margin-top: 1rem;
}


.upload-section {
    margin-bottom: 1.5rem;
    padding: 1.5rem;
    border: 2px dashed var(--border-color);
    border-radius: var(--rounded-lg);
    background-color: var(--primary-bg);
    text-align: center;
}

.payment-instruction {
    background-color: #eef2ff;
    color: #3730a3;
    padding: 1rem;
    border-radius: 0.5rem;
    margin-bottom: 1.5rem;
    font-size: 0.95rem;
    line-height: 1.6;
    text-align: left;
    border-left: 4px solid var(--accent-color);
}

.payment-instruction strong {
    color: var(--accent-hover);
}

.upload-section h3 {
    font-weight: 700;
    font-size: 1.2rem;
    color: var(--primary-text);
    margin-bottom: 0.5rem;
}

.upload-description {
    font-size: 0.9rem;
    color: var(--secondary-text);
    margin-bottom: 1.5rem;
}

.file-input-group {
    margin-bottom: 1rem;
}

.file-input-group span {
    display: block;
    font-weight: 500;
    text-align: left;
    margin-bottom: 8px;
}

.custom-file-upload {
    display: flex;
    align-items: center;
    border: 1px solid var(--border-color);
    background-color: var(--secondary-bg);
    border-radius: 0.5rem;
    padding: 5px;
    cursor: pointer;
    transition: border-color 0.3s, box-shadow 0.3s;
    width: 100%; 
}

.custom-file-upload:hover {
    border-color: var(--accent-color);
    box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.15);
}

.file-upload-button {
    background-color: var(--accent-color);
    color: #fff;
    padding: 8px 16px;
    border-radius: 0.375rem; 
    font-weight: 500;
    font-size: 0.9rem;
    white-space: nowrap; 
    transition: background-color var(--transition-duration) ease;
}

.custom-file-upload:hover .file-upload-button {
    background-color: var(--accent-hover);
}

.file-upload-text {
    margin-left: 12px;
    font-size: 0.9rem;
    color: var(--secondary-text);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis; 
    flex-grow: 1; 
    text-align: left; 
}

#qrcode-container {
    text-align: center;
}

#qrcode-container h2 {
    font-size: 2rem;
    color: #16a34a; 
    font-weight: 700;
    margin-bottom: 0.5rem;
}

#qrcode {
    margin: 25px auto;
    padding: 15px;
    border: 1px solid var(--border-color);
    display: inline-block;
    background: white;
    border-radius: var(--rounded-lg);
}

#qrcode img,
#qrcode canvas {
    display: block;
}

#qrcode-info {
    margin-top: 10px;
    color: var(--primary-text);
    font-weight: 600;
    font-size: 1.1rem;
}

#loading-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(15, 23, 42, 0.8); 
    backdrop-filter: blur(5px);
    -webkit-backdrop-filter: blur(5px);
    display: none; 
    justify-content: center;
    align-items: center;
    z-index: 10000;
    flex-direction: column;
}

#loading-overlay p {
    color: white;
    font-size: 1.1em;
    font-weight: 500;
}

.spinner {
    border: 5px solid rgba(255, 255, 255, 0.3);
    border-radius: 50%;
    border-top: 5px solid #ffffff;
    width: 50px;
    height: 50px;
    animation: spin 1s linear infinite;
    margin-bottom: 20px;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

@media (max-width: 768px) {
    .navbar .nav-links {
        display: none;
    }
    .section {
        padding: 60px 0;
    }
    .section-title {
        font-size: 2rem;
    }
    .form-card {
        padding: 1.5rem;
    }
}

.slot-info-per-class {
    font-size: 0.8rem;
    color: var(--secondary-text);
    margin-top: 8px;
    height: 1.2rem; 
}

.slot-info-per-class span {
    font-weight: 600;
    color: var(--primary-text);
}

.navbar .logo {
    display: flex;
    align-items: center;
    gap: 15px; 
}

.navbar .logo img {
    height: 60px; 
    width: auto;
}

@media (max-width: 768px) {
    .navbar .logo {
        gap: 10px; 
    }

    .navbar .logo img {
        height: 35px; 
    }
}

.whatsapp-btn {
    display: inline-flex; 
    align-items: center;
    justify-content: center; 
    gap: 10px; 
    background-color: #25d366; 
    color: #fff;
    padding: 12px 30px; 
    border-radius: 8px; 
    text-decoration: none;
    font-weight: 600;
    font-size: 1rem;
    transition: background-color 0.3s ease, transform 0.2s ease;
    white-space: nowrap; 
}

.whatsapp-btn:hover {
    background-color: #128c7e; 
    transform: translateY(-2px);
}

.whatsapp-btn img {
    width: 20px; 
    height: 20px;
    filter: brightness(0) invert(1); 
    flex-shrink: 0; 
}

.whatsapp-btn span {
    line-height: 1; 
}

@media (max-width: 480px) {
    .whatsapp-btn {
        width: 100%; 
        padding: 12px 15px; 
        font-size: 0.9rem;
    }
}

.image-preview-modal {
    display: none; 
    position: fixed; 
    z-index: 2000; 
    left: 0;
    top: 0;
    width: 100%; 
    height: 100%; 
    overflow: auto; 
    background-color: rgba(0,0,0,0.7); 
    backdrop-filter: blur(5px); 
    justify-content: center;
    align-items: center;
}

.image-preview-modal-content {
    background-color: #fefefe;
    margin: auto;
    padding: 20px;
    border: 1px solid #888;
    border-radius: 10px;
    width: 90%;
    max-width: 600px;
    box-shadow: 0 5px 15px rgba(0,0,0,0.3);
    position: relative;
    text-align: center;
}

.image-preview-modal-content img {
    max-width: 100%;
    height: auto;
    display: block;
    margin: 0 auto 20px auto;
    border-radius: 8px;
}

.image-preview-modal-content h3 {
    margin-bottom: 15px;
    color: #333;
}
.image-preview-modal-content p {
    font-size: 0.9em;
    color: var(--secondary-text);
    margin-bottom: 20px;
    word-break: break-all;
}
.modal-actions {
    display: flex;
    justify-content: center;
    gap: 15px;
}

.image-preview-close {
    color: #aaa;
    float: right;
    font-size: 35px;
    font-weight: bold;
    position: absolute;
    top: 10px;
    right: 20px;
    cursor: pointer;
}

.image-preview-close:hover,
.image-preview-close:focus {
    color: black;
    text-decoration: none;
    cursor: pointer;
}

.image-preview-confirm-btn {
    background-color: #4CAF50; 
    color: white;
    padding: 10px 20px;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    font-size: 1em;
}

.image-preview-confirm-btn:hover {
    background-color: #45a049;
}

.image-preview-cancel-btn {
    background-color: #f44336;
    color: white;
    padding: 10px 20px;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    font-size: 1em;
}

.image-preview-cancel-btn:hover {
    background-color: #da190b;
}




.custom-modal {
    display: none; 
    position: fixed; 
    z-index: 2000; 
    left: 0;
    top: 0;
    width: 100%; 
    height: 100%; 
    overflow: auto; 
    background-color: rgba(15, 23, 42, 0.6); 
    backdrop-filter: blur(4px); 
    -webkit-backdrop-filter: blur(4px);
    justify-content: center;
    align-items: center;
    padding: 20px;
}

.custom-modal-content {
    background-color: var(--secondary-bg);
    margin: auto;
    padding: 2.5rem;
    border-radius: var(--rounded-lg);
    width: 100%;
    max-width: 500px;
    box-shadow: var(--box-shadow);
    position: relative;
    text-align: center;
    animation: modal-fade-in 0.4s;
}

@keyframes modal-fade-in {
    from { opacity: 0; transform: scale(0.95); }
    to { opacity: 1; transform: scale(1); }
}

.custom-modal-close {
    color: #aaa;
    position: absolute;
    top: 1rem;
    right: 1.5rem;
    font-size: 32px;
    font-weight: bold;
    cursor: pointer;
    line-height: 1;
}

.custom-modal-close:hover,
.custom-modal-close:focus {
    color: var(--primary-text);
}

.custom-modal-body .modal-icon-wrapper {
    width: 80px;
    height: 80px;
    margin: 0 auto 1.5rem auto;
    border-radius: 50%;
    background-color: #eef2ff;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--accent-color);
}

.custom-modal-title {
    font-size: 1.75rem;
    font-weight: 700;
    color: var(--primary-text);
    margin-bottom: 0.75rem;
}

.custom-modal-text {
    font-size: 1rem;
    color: var(--secondary-text);
    margin-bottom: 1.5rem;
}

.rekening-info {
    background-color: var(--primary-bg);
    border: 1px dashed var(--border-color);
    border-radius: 0.5rem;
    padding: 1rem;
    margin-bottom: 1.5rem;
}

.rekening-info .bank-name {
    font-weight: 600;
    color: var(--primary-text);
}

.rekening-info .rekening-number {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--accent-color);
    letter-spacing: 1px;
    margin: 0.25rem 0;
}

.rekening-info .rekening-name {
    font-size: 1rem;
    color: var(--secondary-text);
}

.custom-modal-note {
    font-size: 0.9rem;
    color: var(--secondary-text);
    line-height: 1.6;
}