:root {
    --primary-color: #0f172a;
    /* Slate 900 */
    --primary-hover: #1e293b;
    /* Slate 800 */
    --accent-color: #3b82f6;
    /* Blue 500 */
    --bg-color: #f8fafc;
    /* Slate 50 */
    --card-bg: #ffffff;
    --text-main: #1e293b;
    --text-muted: #64748b;
    --border-color: #e2e8f0;
    --input-bg: #f8fafc;
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --radius: 0.5rem;
}

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

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--bg-color);
    color: var(--text-main);
    line-height: 1.5;
    padding: 2rem 1rem;
}

.container {
    max-width: 800px;
    margin: 0 auto;
}

.header {
    text-align: center;
    margin-bottom: 2.5rem;
}

.header h1 {
    font-size: 2rem;
    font-weight: 600;
    color: var(--primary-color);
    margin-bottom: 0.5rem;
}

.header p {
    color: var(--text-muted);
}

.subscription-form {
    display: flex;
    flex-direction: column;
    gap: 2rem;
}

.form-section {
    background: var(--card-bg);
    padding: 2rem;
    border-radius: var(--radius);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border-color);
}

.section-header {
    margin-bottom: 1.5rem;
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 1rem;
}

.section-header h2 {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--primary-color);
}

.section-header p {
    font-size: 0.875rem;
    color: var(--text-muted);
}

.form-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 1.5rem;
}

@media (min-width: 640px) {
    .form-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .full-width {
        grid-column: span 2;
    }
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.form-group label {
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--primary-color);
}

.form-group input,
.form-group select,
.form-group textarea {
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    background-color: var(--input-bg);
    font-family: inherit;
    font-size: 0.95rem;
    color: var(--text-main);
    transition: all 0.2s ease;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--accent-color);
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.1);
    background-color: #fff;
}

.form-actions {
    margin-top: 1rem;
}

.btn-primary {
    display: block;
    width: 100%;
    padding: 1rem;
    background-color: var(--primary-color);
    color: white;
    border: none;
    border-radius: var(--radius);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: background-color 0.2s;
    box-shadow: var(--shadow-md);
}

.btn-primary:hover {
    background-color: var(--primary-hover);
}

.btn-primary:disabled {
    opacity: 0.7;
    cursor: not-allowed;
}

.feedback-message {
    padding: 1rem;
    border-radius: var(--radius);
    text-align: center;
    font-weight: 500;
    margin-top: 1rem;
}

.feedback-message.success {
    background-color: #ecfdf5;
    color: #047857;
    border: 1px solid #a7f3d0;
}

.feedback-message.error {
    background-color: #fef2f2;
    color: #b91c1c;
    border: 1px solid #fecaca;
}

.hidden {
    display: none !important;
}

/* Modal Styles */
.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 1000;
    animation: fadeIn 0.2s ease-out;
}

.modal-content {
    background-color: white;
    padding: 2rem;
    border-radius: var(--radius);
    box-shadow: var(--shadow-md);
    width: 90%;
    max-width: 500px;
    position: relative;
    animation: slideUp 0.3s ease-out;
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 1rem;
}

.modal-header h3 {
    color: var(--primary-color);
    font-size: 1.25rem;
}

.close-btn {
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--text-muted);
}

.modal-body p {
    color: var(--text-main);
    margin-bottom: 1rem;
    font-size: 0.95rem;
}

.url-copy-container {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 0.5rem;
}

.url-copy-container input {
    flex: 1;
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    background-color: var(--input-bg);
    color: var(--text-muted);
}

.btn-secondary {
    padding: 0.75rem 1.5rem;
    background-color: white;
    border: 1px solid var(--border-color);
    color: var(--primary-color);
    border-radius: var(--radius);
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s;
}

.btn-secondary:hover {
    background-color: var(--bg-color);
    border-color: var(--accent-color);
    color: var(--accent-color);
}

.copy-feedback {
    font-size: 0.85rem;
    color: #047857;
    /* Green */
    text-align: right;
    height: 1.25rem;
    /* Reserve space */
}

.modal-footer {
    margin-top: 1.5rem;
    text-align: right;
}

/* Validation Styles */
.input-invalid {
    border-color: #ef4444 !important;
    /* Red-500 */
    background-color: #fef2f2;
}

.input-valid {
    border-color: #10b981 !important;
    /* Green-500 */
}

.input-error-msg {
    animation: fadeIn 0.3s ease-in-out;
}

@keyframes fadeIn {
    from {
        opacity: 0;
    }

    to {
        opacity: 1;
    }
}

@keyframes slideUp {
    from {
        transform: translateY(20px);
        opacity: 0;
    }

    to {
        transform: translateY(0);
        opacity: 1;
    }
}