:root {
    --bg-start: #2b2cdf;
    --bg-end: #6a2eff;
    --card-bg: rgba(255, 255, 255, 0.12);
    --card-border: rgba(255, 255, 255, 0.18);
    --text-primary: #f8f9ff;
    --text-secondary: #d7d8ff;
    --button-primary: #7d6bff;
    --button-primary-hover: #916dff;
    --button-secondary: rgba(255, 255, 255, 0.14);
    --button-secondary-hover: rgba(255, 255, 255, 0.22);
    --shadow: 0 20px 70px rgba(16, 18, 50, 0.24);
}

[data-theme="dark"] {
    --bg-start: #130f3a;
    --bg-end: #361a7c;
    --card-bg: rgba(12, 11, 26, 0.8);
    --card-border: rgba(126, 97, 255, 0.18);
    --text-primary: #eef1ff;
    --text-secondary: #bdbdff;
    --button-primary: #8e7cff;
    --button-primary-hover: #9f8cff;
    --button-secondary: rgba(255, 255, 255, 0.12);
    --button-secondary-hover: rgba(255, 255, 255, 0.22);
    --shadow: 0 20px 65px rgba(3, 6, 23, 0.4);
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    min-height: 100vh;
    font-family: Inter, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
    color: var(--text-primary);
    background: radial-gradient(circle at top left, rgba(167, 127, 255, 0.32), transparent 30%),
                radial-gradient(circle at bottom right, rgba(86, 219, 255, 0.22), transparent 25%),
                linear-gradient(135deg, var(--bg-start), var(--bg-end));
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 24px;
}

.page-wrapper {
    width: min(1100px, 100%);
    padding: 10px;
}

.theme-switcher {
    display: flex;
    justify-content: flex-end;
    align-items: center;
    gap: 12px;
    margin-bottom: 18px;
    font-size: 0.92rem;
    color: var(--text-secondary);
}

.toggle-btn {
    width: 48px;
    height: 28px;
    border: none;
    border-radius: 999px;
    background: rgba(255, 255, 255, 0.14);
    color: var(--text-primary);
    cursor: pointer;
    transition: transform 0.18s ease, background 0.2s ease;
}

.toggle-btn:hover {
    transform: translateY(-1px);
    background: rgba(255, 255, 255, 0.24);
}

.hero-card {
    display: grid;
    grid-template-columns: 1.3fr 1fr;
    gap: 24px;
    background: rgba(255, 255, 255, 0.08);
    border: 1px solid var(--card-border);
    border-radius: 30px;
    box-shadow: var(--shadow);
    backdrop-filter: blur(22px);
    padding: 32px;
}

.hero-header {
    grid-column: 1 / -1;
    display: flex;
    flex-direction: column;
    gap: 12px;
    margin-bottom: 12px;
}

.hero-header h1 {
    margin: 0;
    font-size: clamp(2rem, 2.7vw, 3rem);
    letter-spacing: -0.04em;
}

.hero-header p {
    margin: 0;
    color: var(--text-secondary);
    max-width: 620px;
    line-height: 1.65;
}

.control-card,
.result-card {
    background: var(--card-bg);
    border: 1px solid rgba(255, 255, 255, 0.12);
    border-radius: 28px;
    padding: 28px;
    display: flex;
    flex-direction: column;
    gap: 18px;
}

.input-label {
    font-size: 0.94rem;
    color: var(--text-secondary);
}

textarea {
    width: 100%;
    border: 1px solid rgba(255, 255, 255, 0.18);
    border-radius: 18px;
    padding: 18px;
    background: rgba(255, 255, 255, 0.08);
    color: var(--text-primary);
    font-size: 1rem;
    resize: vertical;
    min-height: 120px;
    outline: none;
    transition: border-color 0.25s ease, transform 0.2s ease;
}

textarea:focus {
    border-color: rgba(125, 107, 255, 0.9);
    transform: translateY(-1px);
}

.input-tabs {
    display: flex;
    gap: 12px;
    margin-bottom: 18px;
}

.tab-btn {
    padding: 10px 18px;
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 14px;
    background: rgba(255, 255, 255, 0.08);
    color: var(--text-secondary);
    cursor: pointer;
    transition: all 0.2s ease;
    font-weight: 500;
}

.tab-btn:hover {
    border-color: rgba(125, 107, 255, 0.6);
}

.tab-btn.active {
    background: rgba(125, 107, 255, 0.3);
    border-color: rgba(125, 107, 255, 0.8);
    color: var(--text-primary);
}

.tab-content {
    display: none;
}

.tab-content.active {
    display: block;
}

.file-input {
    width: 100%;
    padding: 18px;
    border: 2px dashed rgba(255, 255, 255, 0.2);
    border-radius: 18px;
    background: rgba(255, 255, 255, 0.04);
    color: var(--text-secondary);
    cursor: pointer;
    transition: border-color 0.25s ease;
}

.file-input:hover {
    border-color: rgba(125, 107, 255, 0.6);
}

.pdf-info {
    margin-top: 12px;
    padding: 12px 16px;
    border-radius: 12px;
    background: rgba(255, 255, 255, 0.08);
    color: var(--text-secondary);
    font-size: 0.9rem;
    text-align: center;
}

.options-row,
.buttons-row {
    display: flex;
    flex-wrap: wrap;
    gap: 14px;
}

.option-group {
    display: grid;
    gap: 8px;
    min-width: 150px;
}

.option-group label {
    color: var(--text-secondary);
    font-size: 0.88rem;
}

.option-group input[type="color"] {
    border: none;
    width: 100%;
    height: 44px;
    border-radius: 16px;
    cursor: pointer;
    padding: 0;
}

.btn {
    padding: 15px 22px;
    border-radius: 16px;
    border: none;
    font-weight: 600;
    cursor: pointer;
    transition: transform 0.18s ease, box-shadow 0.2s ease, background 0.2s ease;
}

.btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 18px 40px rgba(58, 61, 140, 0.16);
}

.btn-primary {
    color: #fff;
    background: linear-gradient(135deg, #8f7bff, #5cc3ff);
}

.btn-secondary {
    background: var(--button-secondary);
    color: var(--text-primary);
}

.btn-light {
    background: rgba(255, 255, 255, 0.14);
    color: var(--text-primary);
}

.small-gap {
    gap: 10px;
}

.alert-box {
    min-height: 24px;
    color: #fb7185;
    font-weight: 600;
}

.loading-holder {
    display: none;
    align-items: center;
    gap: 12px;
    color: var(--text-secondary);
}

.spinner {
    width: 24px;
    height: 24px;
    border-radius: 50%;
    border: 4px solid rgba(255, 255, 255, 0.18);
    border-top-color: #ffffff;
    animation: spin 0.9s linear infinite;
}

.qrcode-box {
    display: grid;
    place-items: center;
    min-height: 260px;
    background: #ffffff;
    border: 1px solid rgba(255, 255, 255, 0.12);
    border-radius: 24px;
    padding: 50px;
}

.qrcode-box img,
.qrcode-box canvas {
    padding: 20px;
    background: #ffffff;
    border-radius: 12px;
}

.hint-text {
    color: var(--text-secondary);
    font-size: 0.95rem;
    margin: 0;
}

@keyframes spin {
    from { transform: rotate(0deg); }
    to { transform: rotate(360deg); }
}

@media (max-width: 900px) {
    .hero-card {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 590px) {
    body {
        padding: 14px;
    }

    .hero-card {
        padding: 22px;
    }

    .buttons-row,
    .options-row {
        flex-direction: column;
    }

    .option-group {
        width: 100%;
    }

    .btn {
        width: 100%;
    }
}