:root {
    /* Colors */
    --color-bg-main: #ffffff;
    --color-bg-alt: #f5f7fa;
    --color-text-main: #0f172a;
    --color-text-muted: #64748b;
    --color-accent: #2563eb;
    --color-accent-light: #e0e7ff;
    --color-border: #e5e7eb;
    --color-success-bg: rgba(34, 197, 94, 0.12);
    --color-success-border: rgba(34, 197, 94, 0.3);
    --color-success-text: #166534;
    --color-secondary-btn-bg: #f1f5f9;
    --color-secondary-btn-hover: #e2e8f0;

    /* Font sizes */
    --font-size-base: 1rem;
    --font-size-small: 0.85rem;
    --font-size-label: 0.9rem;
    --font-size-h1: 2.8rem;
    --font-size-h2: 2rem;
    --font-size-card-title: 1.1rem;
    --font-size-card-text: 0.95rem;
    --font-size-footer: 0.85rem;
    --font-size-hero-p: 1.1rem;

    /* Font weights */
    --fw-regular: 400;
    --fw-medium: 500;
    --fw-semibold: 600;
    --fw-bold: 700;

    /* Spacing */
    --spacing-xs: 6px;
    --spacing-sm: 12px;
    --spacing-md: 16px;
    --spacing-lg: 24px;
    --spacing-xl: 28px;
    --spacing-xxl: 32px;
    --spacing-section: 96px;
    --spacing-hero-padding: 120px;

    /* Border radius */
    --radius-sm: 8px;
    --radius-md: 10px;
    --radius-lg: 12px;
    --radius-xl: 16px;

    /* Transition */
    --transition-fast: 0.2s;
    --transition-medium: 0.4s;

    /* Container */
    --container-max: 1200px;
}

/* Reset & base */
* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    font-family: 'Inter', system-ui, -apple-system, BlinkMacSystemFont, sans-serif;
    background: var(--color-bg-main);
    color: var(--color-text-main);
    line-height: 1.6;
}

.container {
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
}

/* Header */
.site-header {
    position: sticky;
    top: 0;
    background: rgba(255, 255, 255, 0.9);
    backdrop-filter: blur(8px);
    border-bottom: 1px solid var(--color-border);
    z-index: 100;
}

.site-header .container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 72px;
}

.logo {
    text-decoration: none;
    font-size: 1.4rem;
    font-weight: var(--fw-bold);
    letter-spacing: -0.02em;
    color: var(--color-text-main);
}

.logo-name {
    font-weight: var(--fw-semibold);
}

.logo-accent {
    font-weight: var(--fw-bold);
    color: #4f46e5;
}

.nav a {
    margin-left: var(--spacing-xl);
    text-decoration: none;
    color: var(--color-text-muted);
    font-weight: var(--fw-medium);
}

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

/* Hero */
.hero {
    padding: var(--spacing-hero-padding) 0;
    background: linear-gradient(180deg, #f8fafc 0%, #ffffff 100%);
}

.hero-bold-neutral {
    background: var(--color-bg-alt);
}

.hero-badge {
    display: inline-block;
    background: var(--color-bg-alt);
    color: var(--color-text-muted);
    font-weight: var(--fw-medium);
    font-size: var(--font-size-small);
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: var(--radius-lg);
    margin-bottom: var(--spacing-md);
}

.hero-bold-neutral .hero-badge {
    background: var(--color-accent-light);
    color: #4f46e5;
}

.hero h1 {
    font-size: var(--font-size-h1);
    max-width: 700px;
    margin-bottom: var(--spacing-md);
}

.hero p {
    font-size: var(--font-size-hero-p);
    color: var(--color-text-muted);
    max-width: 600px;
    margin-bottom: var(--spacing-xxl);
}

.hero-actions {
    display: flex;
    gap: var(--spacing-lg);
}

/* Buttons */
.btn-primary,
.btn-secondary {
    display: inline-block;
    padding: 14px 28px;
    border-radius: var(--radius-sm);
    text-decoration: none;
    font-weight: var(--fw-semibold);
}

.btn-primary {
    background: var(--color-accent);
    color: #fff;
}

.btn-primary:hover {
    opacity: 0.9;
}

.btn-secondary {
    background: var(--color-secondary-btn-bg);
    color: var(--color-text-main);
}

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

/* Sections */
.section {
    padding: var(--spacing-section) 0;
}

.section-alt {
    background: var(--color-bg-alt);
}

.section h2 {
    font-size: var(--font-size-h2);
    margin-bottom: var(--spacing-xxl);
}

.section-intro {
    max-width: 720px;
    margin: 0 auto var(--spacing-xl);
    font-size: 1.05rem;
    color: #475569;
    text-align: center;
}

/* Grid / Cards */
.grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: var(--spacing-xxl);
}

.card {
    background: var(--color-bg-main);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-xl);
    padding: var(--spacing-xl);
    transition: transform var(--transition-fast), box-shadow var(--transition-fast);
    text-decoration: none;
    color: inherit;
    max-width: 420px;
    width: 100%;
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
    position: relative;
}

.card-badge {
    position: absolute;
    top: var(--spacing-md);
    right: var(--spacing-md);

    background: transparent;
    color: var(--color-text-muted);

    padding: 4px 8px;
    border-radius: var(--radius-md);

    font-size: 1rem;
    line-height: 1;

    pointer-events: none;
}

.card:hover {
    transform: translateY(-4px);
    box-shadow: 0 12px 30px rgba(0,0,0,0.08);
}

.card-image {
    height: 160px;
    padding: var(--spacing-md);

    background: var(--color-bg-alt);
    border-radius: var(--radius-xl);

    display: flex;
    align-items: center;
    justify-content: center;

    overflow: hidden;
}

.card-image img {
    max-width: 100%;
    max-height: 100%;

    object-fit: contain;
    display: block;

    border-radius: var(--radius-lg);

    box-shadow: inset 0 0 0 1px var(--color-border);
}

/* About Section */
.about-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: var(--spacing-xxl);
}

.about-item {
    background: var(--color-bg-main);
    border-radius: var(--radius-xl);
    padding: var(--spacing-xl) var(--spacing-lg);
    text-align: center;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.04);
    user-select: none;
}

.about-icon {
    font-size: 2rem;
    margin-bottom: var(--spacing-md);
}

/* Contact / Form */
.contact-form {
    max-width: 520px;
    margin-top: var(--spacing-xxl);
}

#contact a {
    color: var(--color-accent);
    text-decoration: none;
    font-weight: var(--fw-medium);
}

#contact a:hover {
    text-decoration: underline;
}

.form-group {
    display: flex;
    flex-direction: column;
    margin-bottom: var(--spacing-xl);
}

.form-group label {
    font-size: var(--font-size-label);
    font-weight: var(--fw-medium);
    margin-bottom: var(--spacing-xs);
    color: var(--color-text-muted);
}

.form-group input,
.form-group textarea {
    padding: 12px 14px;
    border-radius: var(--radius-md);
    border: 1px solid var(--color-border);
    font-family: inherit;
    font-size: var(--font-size-base);
    background: var(--color-bg-main);
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--color-accent);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.15);
}

.alert {
    padding: var(--spacing-md) var(--spacing-lg);
    border-radius: var(--radius-md);
    margin-bottom: var(--spacing-xxl);
    font-weight: var(--fw-medium);
}

.alert-success {
    background: var(--color-success-bg);
    border: 1px solid var(--color-success-border);
    color: var(--color-success-text);
    animation: fadeIn var(--transition-medium) ease-out;
}

.alert-error {
    background: rgba(239, 68, 68, 0.12);
    border: 1px solid rgba(239, 68, 68, 0.3);
    color: #7f1d1d;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(-6px); }
    to { opacity: 1; transform: translateY(0); }
}

/* Project title */
.project-title {
    margin-bottom: var(--spacing-xxl);
}

/* Screenshot */

.screenshot-grid-fixed {
    display: grid;
    grid-template-columns: repeat(auto-fill, 240px);
    gap: var(--spacing-lg);
    justify-content: flex-start;
    margin: var(--spacing-xxl) 0;
}

.screenshot {
    width: 240px;
    height: 420px;
    padding: var(--spacing-md);
    background: var(--color-bg-alt);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-xl);
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
}

.screenshot img {
    max-width: 100%;
    max-height: 100%;
    object-fit: contain;
    border-radius: var(--radius-lg);
}

/* Download */

.download-app {
    display: flex;
    gap: var(--spacing-lg);
    margin-top: var(--spacing-xxl);
    flex-wrap: wrap;
    align-items: center;
}

.download-app h3 {
    width: 100%;
    font-size: var(--font-size-h2);
    margin-bottom: var(--spacing-md);
}

.download-app a {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: 12px 20px;
    background: #f1f1f1;
    border-radius: var(--radius-xl);
    text-decoration: none;
    font-weight: var(--fw-semibold);
    color: var(--color-text-main);
    transition: background 0.2s;
}

.download-app a:hover {
    background: #e0e0e0;
}

.download-app img.store-logo {
    width: 300px;
    max-width: 100%;
    height: auto;
}

/* Previous versions */
.previous-versions {
    margin-top: var(--spacing-xxl);
}

.previous-versions h3 {
    font-size: 1.4rem;
    margin-bottom: var(--spacing-lg);
}

.previous-versions.compact h3 {
    font-size: 1.2rem;
    color: var(--color-text-muted);
}

.previous-versions .version-table {
    width: 100%;
    border-collapse: collapse;
    background: var(--color-bg-main);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    overflow: hidden;
}

.previous-versions .version-table thead {
    background: var(--color-bg-alt);
}

.previous-versions .version-table th {
    text-align: left;
    padding: 14px 16px;
    font-size: 0.9rem;
    font-weight: var(--fw-semibold);
    color: var(--color-text-muted);
    border-bottom: 1px solid var(--color-border);
}

.previous-versions .version-table td {
    padding: 14px 16px;
    font-size: 0.95rem;
    border-bottom: 1px solid var(--color-border);
    vertical-align: middle;
}

.previous-versions .version-table tr:last-child td {
    border-bottom: none;
}

.previous-versions .version-table tbody tr:hover {
    background: rgba(37, 99, 235, 0.04);
}

.previous-versions .version-table a {
    display: inline-block;
    padding: 6px 14px;
    font-size: 0.85rem;
    font-weight: var(--fw-medium);
    border-radius: 999px;
    background: var(--color-secondary-btn-bg);
    color: var(--color-text-main);
    text-decoration: none;
    transition: background var(--transition-fast), transform var(--transition-fast);
}

.previous-versions .version-table a:hover {
    background: var(--color-secondary-btn-hover);
    transform: translateY(-1px);
}

.previous-versions .version-table td:empty::after {
    content: "—";
    color: var(--color-text-muted);
    font-size: 0.85rem;
}

.version-table a {
    font-weight: 600;
}

.muted {
    opacity: 0.5;
}

/* Footer */
.site-footer {
    border-top: 1px solid var(--color-border);
    padding: var(--spacing-lg) 0;
}

.footer-copy {
    text-align: center;
    font-size: var(--font-size-footer);
    color: var(--color-text-muted);
}

/* Responsive */
@media (max-width: 900px) {
    .about-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 520px) {
    .about-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 640px) {
    .previous-versions .version-table th,
    .previous-versions .version-table td {
        padding: 10px 12px;
        font-size: 0.85rem;
    }
}