:root {
    --page-bg: #f3f6fb;
    --panel-bg: rgba(255, 255, 255, 0.86);
    --panel-border: rgba(15, 23, 42, 0.08);
    --text-strong: #101828;
    --text-muted: #667085;
    --accent: #2563eb;
    --accent-strong: #1d4ed8;
    --error-bg: #fee2e2;
    --error-text: #b91c1c;
    --shadow-soft: 0 20px 45px rgba(15, 23, 42, 0.08);
    --radius: 16px;
    --font-family: "Inter", "Segoe UI", system-ui, -apple-system, BlinkMacSystemFont, sans-serif;
}

body.dark {
    --page-bg: #050709;
    --panel-bg: rgba(17, 25, 40, 0.9);
    --panel-border: rgba(255, 255, 255, 0.06);
    --text-strong: #f5f7fb;
    --text-muted: #a0aec0;
    --accent: #60a5fa;
    --accent-strong: #3b82f6;
    --error-bg: rgba(248, 113, 113, 0.15);
    --error-text: #fecaca;
    --shadow-soft: 0 20px 45px rgba(5, 7, 9, 0.6);
}

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

body {
    font-family: var(--font-family);
    min-height: 100vh;
    background: var(--page-bg);
    color: var(--text-strong);
    line-height: 1.6;
    transition: background 0.3s ease, color 0.3s ease;
}

.background-texture {
    position: fixed;
    inset: 0;
    background-image: radial-gradient(circle at 1px 1px, rgba(15, 23, 42, 0.08) 1px, transparent 0);
    background-size: 40px 40px;
    opacity: 0.25;
    pointer-events: none;
    mix-blend-mode: multiply;
}

body.dark .background-texture {
    opacity: 0.15;
    mix-blend-mode: screen;
}

.app-shell {
    position: relative;
    max-width: 960px;
    margin: 0 auto;
    padding: 48px 24px 64px;
}

.hero {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    gap: 24px;
    margin-bottom: 32px;
}

.hero-copy h1 {
    font-size: clamp(2rem, 5vw, 2.75rem);
    font-weight: 700;
    letter-spacing: -0.04em;
    margin-bottom: 12px;
}

.subtitle {
    color: var(--text-muted);
    max-width: 36rem;
}

.eyebrow {
    text-transform: uppercase;
    font-size: 0.75rem;
    letter-spacing: 0.2em;
    color: var(--text-muted);
    margin-bottom: 8px;
}

.theme-switch {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    padding: 10px 18px;
    border-radius: 999px;
    border: 1px solid var(--panel-border);
    background: var(--panel-bg);
    color: var(--text-strong);
    cursor: pointer;
    box-shadow: var(--shadow-soft);
    transition: transform 0.2s ease, border-color 0.2s ease;
}

.theme-switch:hover {
    transform: translateY(-2px);
}

.switch-icon {
    font-size: 1.1rem;
}

.switch-label {
    font-weight: 500;
}

.panel {
    background: var(--panel-bg);
    border: 1px solid var(--panel-border);
    border-radius: var(--radius);
    padding: 24px;
    box-shadow: var(--shadow-soft);
    backdrop-filter: blur(24px);
    margin-bottom: 28px;
}

.input-section > label {
    display: block;
    color: var(--text-muted);
    font-weight: 600;
    margin-bottom: 10px;
}

textarea {
    width: 100%;
    border-radius: 12px;
    border: 1px solid var(--panel-border);
    background: rgba(255, 255, 255, 0.6);
    color: var(--text-strong);
    padding: 16px 18px;
    font-size: 1rem;
    resize: vertical;
    min-height: 240px;
    transition: border-color 0.2s ease, background 0.2s ease;
}

body.dark textarea {
    background: rgba(15, 23, 42, 0.7);
}

textarea:focus {
    outline: none;
    border-color: var(--accent);
}

select {
    width: 100%;
    border-radius: 10px;
    border: 1px solid var(--panel-border);
    padding: 11px 36px 11px 12px;
    font-size: 0.95rem;
    background: rgba(255, 255, 255, 0.7);
    color: var(--text-strong);
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath fill='%23667085' d='M6 8L2 4h8z'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 12px center;
}

body.dark select {
    background: rgba(15, 23, 42, 0.8);
}

.controls-grid {
    margin-top: 16px;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: 16px;
    align-items: end;
}

.control-block label {
    display: block;
    font-size: 0.85rem;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--text-muted);
    margin-bottom: 6px;
}

button {
    font-family: inherit;
    border: none;
    cursor: pointer;
}

.primary {
    grid-column: span 1;
    background: linear-gradient(135deg, var(--accent), var(--accent-strong));
    color: #fff;
    border-radius: 12px;
    padding: 14px 20px;
    font-weight: 600;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    transition: transform 0.15s ease, box-shadow 0.2s ease;
    box-shadow: 0 15px 35px rgba(37, 99, 235, 0.35);
}

.primary:hover {
    transform: translateY(-1px);
}

.primary:disabled {
    opacity: 0.6;
    cursor: not-allowed;
    box-shadow: none;
}

.btn-loading {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    font-size: 0.9rem;
}

.btn-loading::before {
    content: "";
    width: 16px;
    height: 16px;
    border: 2px solid rgba(255, 255, 255, 0.3);
    border-top-color: #fff;
    border-radius: 50%;
    animation: spin 0.9s linear infinite;
}

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

.inline-feedback {
    margin-top: 16px;
    padding: 12px 14px;
    border-radius: 12px;
    font-size: 0.9rem;
    border: 1px solid transparent;
}

.inline-feedback[hidden] {
    display: none;
}

.inline-feedback {
    background: var(--error-bg);
    color: var(--error-text);
    border-color: rgba(185, 28, 28, 0.15);
}

.preview-section .inline-feedback {
    margin-top: 0;
    margin-bottom: 16px;
}

.preview-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    gap: 16px;
    margin-bottom: 16px;
}

.preview-header h2 {
    font-size: 1.15rem;
    margin-bottom: 4px;
}

.preview-subtitle {
    color: var(--text-muted);
    font-size: 0.9rem;
}

.font-pill {
    padding: 8px 14px;
    border-radius: 999px;
    background: rgba(37, 99, 235, 0.12);
    color: var(--accent-strong);
    font-weight: 600;
    font-size: 0.85rem;
}

body.dark .font-pill {
    background: rgba(96, 165, 250, 0.12);
}

.preview-wrapper {
    display: grid;
    grid-template-columns: 40px minmax(0, 1fr) 40px;
    gap: 16px;
    align-items: center;
}

.page-btn {
    width: 40px;
    height: 40px;
    border-radius: 12px;
    border: 1px solid var(--panel-border);
    background: transparent;
    color: var(--text-strong);
    font-size: 1rem;
}

.page-btn:disabled {
    opacity: 0.4;
    cursor: not-allowed;
}

.preview-container {
    position: relative;
    border-radius: 18px;
    padding: 20px;
    background: rgba(241, 245, 249, 0.8);
    border: 1px dashed rgba(71, 85, 105, 0.2);
}

body.dark .preview-container {
    background: rgba(15, 23, 42, 0.5);
    border-color: rgba(148, 163, 184, 0.25);
}

#preview-image {
    width: 100%;
    height: auto;
    max-height: 640px;
    border-radius: 8px;
    box-shadow: 0 15px 35px rgba(15, 23, 42, 0.25);
}

.preview-footer {
    margin-top: 18px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 16px;
    color: var(--text-muted);
}

.download-controls {
    display: flex;
    gap: 10px;
}

.download-btn {
    padding: 10px 16px;
    border-radius: 10px;
    background: var(--text-strong);
    color: #fff;
    text-decoration: none;
    font-size: 0.9rem;
    font-weight: 600;
}

.download-btn.ghost {
    background: transparent;
    border: 1px solid var(--panel-border);
    color: var(--text-strong);
}

.app-footer {
    text-align: center;
    color: var(--text-muted);
    font-size: 0.85rem;
    margin-top: 24px;
}

[hidden] {
    display: none !important;
}

@media (max-width: 720px) {
    .hero {
        flex-direction: column;
    }

    .controls-grid {
        grid-template-columns: 1fr;
    }

    .preview-wrapper {
        grid-template-columns: 32px minmax(0, 1fr) 32px;
    }

    .download-controls {
        width: 100%;
        flex-direction: column;
    }

    .download-btn,
    .primary,
    select,
    textarea {
        width: 100%;
    }
}