:root {
    /* Dark Theme (Default) */
    --bg-color: #050505;
    --card-bg: rgba(15, 15, 18, 0.4);
    --text-primary: #ffffff;
    --text-secondary: #a1a1aa;
    --accent-color: #3b82f6;
    --accent-glow: rgba(59, 130, 246, 0.4);
    --border-color: rgba(255, 255, 255, 0.08);
    --input-bg: rgba(0, 0, 0, 0.3);
    --glass-blur: 24px;
    --header-height: 70px;
    --crystal-shine: linear-gradient(135deg, rgba(255,255,255,0.1) 0%, rgba(255,255,255,0) 50%, rgba(255,255,255,0.05) 100%);
}

[data-theme="light"] {
    --bg-color: #f1f5f9;
    --card-bg: rgba(255, 255, 255, 0.5);
    --text-primary: #0f172a;
    --text-secondary: #64748b;
    --accent-color: #2563eb;
    --accent-glow: rgba(37, 99, 235, 0.2);
    --border-color: rgba(0, 0, 0, 0.1);
    --input-bg: rgba(255, 255, 255, 0.6);
    --crystal-shine: linear-gradient(135deg, rgba(255,255,255,0.4) 0%, rgba(255,255,255,0) 50%, rgba(255,255,255,0.2) 100%);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    -webkit-tap-highlight-color: transparent;
}

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--bg-color);
    color: var(--text-primary);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    transition: background-color 0.5s ease;
    overflow-x: hidden;
}

#bg-canvas {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
    pointer-events: none;
    opacity: 0.8;
}

header {
    height: var(--header-height);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 40px;
    background: rgba(var(--bg-color), 0.2);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 100;
}

.logo {
    height: 32px;
    transition: transform 0.3s ease;
}

.nav-actions {
    display: flex;
    gap: 15px;
    align-items: center;
}

/* Crystal Card Effect */
.crystal {
    background: var(--card-bg) !important;
    backdrop-filter: blur(var(--glass-blur)) !important;
    border: 1px solid var(--border-color) !important;
    position: relative;
    overflow: hidden;
}

.crystal::before {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: var(--crystal-shine);
    pointer-events: none;
    z-index: 1;
}

/* Form Card */
.form-card {
    border-radius: 28px;
    padding: 30px;
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
    z-index: 2;
    max-width: 480px;
}

.hero-text h1 {
    font-size: 2rem;
    font-weight: 800;
    margin-bottom: 8px;
    letter-spacing: -0.03em;
}

.hero-text p {
    color: var(--text-secondary);
    font-size: 0.95rem;
    margin-bottom: 25px;
}

.input-group {
    margin-bottom: 18px;
    position: relative;
    z-index: 2;
}

.input-group label {
    display: block;
    font-size: 0.82rem;
    font-weight: 600;
    margin-bottom: 8px;
    opacity: 0.9;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.input-group input[type="text"] {
    width: 100%;
    background: var(--input-bg);
    border: 1px solid var(--border-color);
    color: var(--text-primary);
    padding: 12px 16px;
    border-radius: 12px;
    font-size: 1rem;
    outline: none;
    transition: all 0.3s ease;
}

.input-group input[type="text"]:focus {
    border-color: var(--accent-color);
    box-shadow: 0 0 0 4px var(--accent-glow);
}

/* Styling Grid */
.styling-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 15px;
}

.color-picker {
    appearance: none;
    width: 100%;
    height: 42px;
    background: var(--input-bg);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    cursor: pointer;
    padding: 4px;
}

.color-picker::-webkit-color-swatch-wrapper { padding: 0; }
.color-picker::-webkit-color-swatch { border-radius: 8px; border: none; }

.style-selector {
    display: flex;
    gap: 10px;
    background: var(--input-bg);
    padding: 6px;
    border-radius: 14px;
    border: 1px solid var(--border-color);
}

.style-selector label {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 8px;
    font-size: 0.8rem;
    font-weight: 600;
    cursor: pointer;
    border-radius: 10px;
    transition: all 0.2s ease;
    text-transform: none;
    letter-spacing: normal;
    margin-bottom: 0;
}

.style-selector input { display: none; }
.style-selector label:has(input:checked) {
    background: var(--accent-color);
    color: white;
}

.d-none {
    display: none !important;
}

/* Drop Zone */
.drop-zone {
    transition: all 0.3s ease;
}

.drop-zone.drag-over {
    background: var(--accent-glow);
    border-color: var(--accent-color);
    transform: scale(1.02);
}

.custom-file-upload {
    display: block;
    width: 100%;
    padding: 20px 16px;
    background: var(--input-bg);
    border: 2px dashed var(--border-color);
    border-radius: 15px;
    text-align: center;
    cursor: pointer;
    color: var(--text-secondary);
    transition: all 0.3s ease;
}

#logo {
    display: none;
}

.custom-file-upload:hover {
    border-color: var(--accent-color);
    color: var(--text-primary);
}

/* Layout */
main {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
}

.app-container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 40px;
    max-width: 1100px;
    width: 100%;
    align-items: flex-start;
}

.preview-section {
    position: sticky;
    top: calc(var(--header-height) + 20px);
}

@media (max-width: 950px) {
    .app-container { grid-template-columns: 1fr; }
    .form-card { margin: 0 auto; }
}

/* Preview */
.qr-container {
    width: 100%;
    max-width: 420px;
    aspect-ratio: 1/1;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 40px;
    margin: 0 auto;
    padding: 20px;
    box-shadow: 0 30px 60px -15px rgba(0,0,0,0.6);
}

#qrcodeimg {
    width: 100%;
    height: 100%;
    background: white;
    padding: 5px;
    border-radius: 20px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.1);
}

/* GitHub Link Fix */
.github-link {
    display: flex !important;
    visibility: visible !important;
    opacity: 1 !important;
    width: 40px !important;
    height: 40px !important;
    color: var(--text-primary) !important;
}

.icon-btn {
    background: var(--input-bg);
    border: 1px solid var(--border-color);
    color: var(--text-primary);
    width: 40px;
    height: 40px;
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    text-decoration: none;
    transition: all 0.2s ease;
}

.icon-btn:hover {
    border-color: var(--accent-color);
    background: var(--accent-glow);
}

.icon-btn svg {
    width: 22px;
    height: 22px;
}

.lang-select {
    background: var(--input-bg);
    border: 1px solid var(--border-color);
    color: var(--text-primary);
    padding: 8px 12px;
    border-radius: 12px;
    font-size: 0.9rem;
    cursor: pointer;
    outline: none;
}

/* Slider */
.logo-container {
    display: flex;
    align-items: center;
    gap: 12px;
}

.logo-text {
    font-size: 1.5rem;
    font-weight: 800;
    letter-spacing: -0.5px;
    color: var(--text-primary);
    text-transform: uppercase;
    background: linear-gradient(135deg, var(--text-primary) 0%, var(--accent-color) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

input[type="range"] {
    flex: 1;
    height: 6px;
    background: var(--border-color);
    border-radius: 3px;
    appearance: none;
    outline: none;
}

input[type="range"]::-webkit-slider-thumb {
    appearance: none;
    width: 20px;
    height: 20px;
    background: var(--accent-color);
    border-radius: 50%;
    cursor: pointer;
    box-shadow: 0 0 10px var(--accent-glow);
}

.value-badge {
    background: var(--accent-color);
    color: white;
    padding: 4px 10px;
    border-radius: 10px;
    font-size: 0.85rem;
    font-weight: 700;
}

/* Footer */
.footer-slim {
    padding: 15px;
    text-align: center;
    border-top: 1px solid var(--border-color);
    font-size: 0.85rem;
    color: var(--text-secondary);
}

.copyright-link {
    color: var(--text-primary);
    text-decoration: none;
    font-weight: 600;
}

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

.fade-in {
    animation: fadeIn 0.8s cubic-bezier(0.16, 1, 0.3, 1) forwards;
}