/* ═══════════════════════════════════════════════════════════════════
   CSV ↔ JSON Converter — ToolHub Stylesheet
   12-section architecture
   ═══════════════════════════════════════════════════════════════════ */

/* ─── 1. Variables & Theme ────────────────────────────────────────── */
:root {
    /* Colors — Light */
    --color-bg:            #f5f6f8;
    --color-surface:       #ffffff;
    --color-text:          #1a1a2e;
    --color-text-secondary:#555770;
    --color-border:        #d8d9e0;
    --color-accent:        #4361ee;
    --color-accent-hover:  #3a56d4;
    --color-accent-light:  #eef0ff;
    --color-error:         #d63031;
    --color-error-bg:      #ffeaea;
    --color-success:       #00b894;
    --color-success-bg:    #eafff8;

    /* Layout */
    --header-height:      56px;
    --banner-height:      38px;
    --footer-height:      38px;
    --container-max:      800px;
    --radius-sm:          6px;
    --radius-md:          10px;
    --radius-lg:          14px;
    --radius-pill:        9999px;

    /* Shadows */
    --shadow-sm:          0 1px 3px rgba(0,0,0,0.06);
    --shadow-md:          0 4px 12px rgba(0,0,0,0.08);
    --shadow-lg:          0 8px 30px rgba(0,0,0,0.12);

    /* Spacing */
    --space-xs:           4px;
    --space-sm:           8px;
    --space-md:           16px;
    --space-lg:           24px;
    --space-xl:           32px;
    --space-2xl:          48px;

    /* Typography */
    --font-family:        'Segoe UI', system-ui, -apple-system, sans-serif;
    --font-mono:          'Cascadia Code', 'Fira Code', 'Consolas', monospace;
    --font-size-xs:       0.75rem;
    --font-size-sm:       0.85rem;
    --font-size-base:     1rem;
    --font-size-lg:       1.15rem;
    --font-size-xl:       1.5rem;
    --font-size-2xl:      1.8rem;

    /* Donate */
    --donate-bg:          #FFDD00;
    --donate-color:       #1a1a2e;

    /* Transition */
    --transition:         0.2s ease;
}

html.theme-dark {
    --color-bg:            #0f0f1a;
    --color-surface:       #1a1a2e;
    --color-text:          #e8e8f0;
    --color-text-secondary:#a0a0b8;
    --color-border:        #2d2d44;
    --color-accent:        #6c83f5;
    --color-accent-hover:  #8094f7;
    --color-accent-light:  #1e2248;
    --color-error:         #ff7675;
    --color-error-bg:      #3d1a1a;
    --color-success:       #55efc4;
    --color-success-bg:    #1a3d32;
    --shadow-sm:           0 1px 3px rgba(0,0,0,0.25);
    --shadow-md:           0 4px 12px rgba(0,0,0,0.35);
    --shadow-lg:           0 8px 30px rgba(0,0,0,0.45);
}

/* ─── 2. Base & Reset ─────────────────────────────────────────────── */
*, *::before, *::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-family);
    font-size: var(--font-size-base);
    line-height: 1.6;
    color: var(--color-text);
    background-color: var(--color-bg);
    padding-top: calc(var(--header-height) + var(--banner-height) + var(--space-md));
    padding-bottom: calc(var(--footer-height) + 72px + var(--space-lg));
    min-height: 100vh;
}

a {
    color: var(--color-accent);
    text-decoration: none;
}

a:hover {
    text-decoration: underline;
}

img {
    display: inline-block;
    vertical-align: middle;
}

/* ─── 3. Layout & Containers ──────────────────────────────────────── */
.container {
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 var(--space-md);
}

.tool-card {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    padding: var(--space-xl);
    margin-bottom: var(--space-xl);
}

/* ─── 4. Typography & Utility ─────────────────────────────────────── */
.tool-title {
    font-size: var(--font-size-2xl);
    font-weight: 700;
    margin-bottom: var(--space-sm);
    color: var(--color-text);
    line-height: 1.2;
}

.tool-subtitle {
    font-size: var(--font-size-sm);
    color: var(--color-text-secondary);
    margin-bottom: var(--space-lg);
    line-height: 1.5;
}

.section-title {
    font-size: var(--font-size-lg);
    font-weight: 600;
    margin-bottom: var(--space-md);
    color: var(--color-text);
}

.no-preview {
    color: var(--color-text-secondary);
    font-style: italic;
    text-align: center;
    padding: var(--space-lg);
}

.preview-more {
    color: var(--color-text-secondary);
    font-size: var(--font-size-sm);
    text-align: center;
    padding: var(--space-sm);
    font-style: italic;
}

/* ─── 5. Components ───────────────────────────────────────────────── */

/* — Header — */
.site-header {
    position: sticky;
    top: 0;
    z-index: 50;
    height: var(--header-height);
    background: var(--color-surface);
    border-bottom: 1px solid var(--color-border);
    box-shadow: var(--shadow-sm);
}

.header-inner {
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 var(--space-md);
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.logo-link {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    text-decoration: none;
    color: var(--color-text);
    font-weight: 700;
    font-size: var(--font-size-lg);
}

.logo-link:hover {
    text-decoration: none;
}

.logo-img {
    width: 32px;
    height: 32px;
}

.logo-text {
    letter-spacing: -0.02em;
}

.header-actions {
    display: flex;
    align-items: center;
    gap: var(--space-md);
}

/* — Language Switcher — */
.lang-switch {
    display: flex;
    gap: var(--space-xs);
}

.lang-pill {
    padding: var(--space-xs) var(--space-sm);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-pill);
    background: var(--color-surface);
    color: var(--color-text-secondary);
    font-size: var(--font-size-xs);
    font-weight: 600;
    cursor: pointer;
    transition: background var(--transition), color var(--transition), border-color var(--transition);
    line-height: 1.4;
    letter-spacing: 0.04em;
}

.lang-pill:hover {
    background: var(--color-accent-light);
    border-color: var(--color-accent);
    color: var(--color-accent);
}

.lang-pill.active {
    background: var(--color-accent);
    border-color: var(--color-accent);
    color: #fff;
}

.lang-pill:focus-visible {
    outline: 2px solid var(--color-accent);
    outline-offset: 2px;
}

/* — Theme Toggle — */
.theme-toggle {
    width: 36px;
    height: 36px;
    border-radius: 50%;
    border: 1px solid var(--color-border);
    background: var(--color-surface);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.1rem;
    transition: background var(--transition), border-color var(--transition);
}

.theme-toggle:hover {
    background: var(--color-accent-light);
    border-color: var(--color-accent);
}

.theme-toggle:focus-visible {
    outline: 2px solid var(--color-accent);
    outline-offset: 2px;
}

/* — Sub-site Banner — */
.subsite-banner {
    position: sticky;
    top: var(--header-height);
    z-index: 49;
    height: var(--banner-height);
    background: var(--color-accent);
    color: #fff;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-xs);
    font-size: var(--font-size-sm);
    font-weight: 500;
}

.subsite-banner a {
    color: #fff;
    text-decoration: underline;
}

.subsite-banner a:hover {
    text-decoration: underline;
    opacity: 0.9;
}

/* — Buttons — */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-xs);
    padding: var(--space-sm) var(--space-md);
    border: 1px solid transparent;
    border-radius: var(--radius-md);
    font-size: var(--font-size-sm);
    font-weight: 600;
    cursor: pointer;
    transition: background var(--transition), color var(--transition), border-color var(--transition), opacity var(--transition);
    line-height: 1.5;
    white-space: nowrap;
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.btn:focus-visible {
    outline: 2px solid var(--color-accent);
    outline-offset: 2px;
}

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

.btn-primary:hover:not(:disabled) {
    background: var(--color-accent-hover);
    border-color: var(--color-accent-hover);
}

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

.btn-secondary:hover:not(:disabled) {
    background: var(--color-accent-light);
}

.btn-outline {
    background: transparent;
    color: var(--color-text-secondary);
    border-color: var(--color-border);
}

.btn-outline:hover:not(:disabled) {
    background: var(--color-accent-light);
    color: var(--color-accent);
    border-color: var(--color-accent);
}

.btn-sm {
    padding: var(--space-xs) var(--space-sm);
    font-size: var(--font-size-xs);
}

/* — Form Inputs — */
.form-input {
    width: 100%;
    padding: var(--space-sm) var(--space-md);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    background: var(--color-surface);
    color: var(--color-text);
    font-size: var(--font-size-sm);
    font-family: var(--font-family);
    transition: border-color var(--transition), box-shadow var(--transition);
    appearance: none;
    -webkit-appearance: none;
}

.form-input:focus {
    outline: none;
    border-color: var(--color-accent);
    box-shadow: 0 0 0 3px rgba(67, 97, 238, 0.15);
}

html.theme-dark .form-input:focus {
    box-shadow: 0 0 0 3px rgba(108, 131, 245, 0.25);
}

select.form-input {
    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='%23555' d='M6 8L1 3h10z'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 12px center;
    padding-right: 32px;
}

/* — Toggle Switch — */
.direction-toggle {
    display: flex;
    align-items: center;
    gap: var(--space-md);
    margin-bottom: var(--space-lg);
    font-size: var(--font-size-sm);
    font-weight: 600;
    color: var(--color-text-secondary);
    justify-content: center;
}

.toggle-switch {
    position: relative;
    display: inline-block;
    width: 52px;
    height: 28px;
    flex-shrink: 0;
}

.toggle-switch input {
    opacity: 0;
    width: 0;
    height: 0;
}

.toggle-slider {
    position: absolute;
    cursor: pointer;
    top: 0; left: 0; right: 0; bottom: 0;
    background-color: var(--color-accent);
    border-radius: var(--radius-pill);
    transition: background var(--transition);
}

.toggle-slider::before {
    position: absolute;
    content: "";
    height: 22px;
    width: 22px;
    left: 3px;
    bottom: 3px;
    background-color: #fff;
    border-radius: 50%;
    transition: transform var(--transition);
}

.toggle-switch input:checked + .toggle-slider {
    background-color: var(--color-accent);
}

.toggle-switch input:checked + .toggle-slider::before {
    transform: translateX(24px);
}

.toggle-switch input:focus-visible + .toggle-slider {
    outline: 2px solid var(--color-accent);
    outline-offset: 2px;
}

/* — Legal Footer — */
.legal-footer {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    z-index: 9998;
    height: var(--footer-height);
    background: var(--color-surface);
    border-top: 1px solid var(--color-border);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-xs);
    font-size: var(--font-size-xs);
    color: var(--color-text-secondary);
}

.legal-footer a {
    color: var(--color-accent);
}

/* ─── 6. Tool-Specific (CSV/JSON Converter) ───────────────────────── */

/* — Drop Zone — */
.drop-zone {
    border: 2px dashed var(--color-border);
    border-radius: var(--radius-lg);
    padding: var(--space-2xl) var(--space-lg);
    text-align: center;
    cursor: pointer;
    transition: border-color var(--transition), background var(--transition);
    margin-bottom: var(--space-lg);
    background: var(--color-bg);
}

.drop-zone:hover,
.drop-zone:focus-visible {
    border-color: var(--color-accent);
    background: var(--color-accent-light);
}

.drop-zone.dragover {
    border-color: var(--color-accent);
    background: var(--color-accent-light);
    border-style: solid;
}

.drop-zone-icon {
    font-size: 2.5rem;
    margin-bottom: var(--space-sm);
}

.drop-zone-text {
    color: var(--color-text-secondary);
    font-size: var(--font-size-sm);
}

/* — File Info — */
.file-info {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: var(--space-md);
    padding: var(--space-sm) var(--space-md);
    background: var(--color-accent-light);
    border-radius: var(--radius-md);
    font-size: var(--font-size-sm);
    margin-bottom: var(--space-lg);
    color: var(--color-text);
}

.file-info #fileName {
    font-weight: 600;
}

/* — Settings Row — */
.settings-row {
    display: flex;
    gap: var(--space-lg);
    margin-bottom: var(--space-lg);
    flex-wrap: wrap;
}

.setting-group {
    flex: 1;
    min-width: 180px;
}

.setting-group label {
    display: block;
    font-size: var(--font-size-sm);
    font-weight: 600;
    margin-bottom: var(--space-xs);
    color: var(--color-text-secondary);
}

/* — Action Row — */
.action-row {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-sm);
    margin-bottom: var(--space-md);
}

/* — Example Row — */
.example-row {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-sm);
    margin-bottom: var(--space-lg);
}

/* — Preview Section — */
.preview-section {
    margin-bottom: var(--space-lg);
}

.preview-area {
    max-height: 320px;
    overflow: auto;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    background: var(--color-bg);
    padding: var(--space-sm);
}

.preview-table {
    width: 100%;
    border-collapse: collapse;
    font-size: var(--font-size-sm);
}

.preview-table th,
.preview-table td {
    padding: var(--space-xs) var(--space-sm);
    text-align: left;
    border-bottom: 1px solid var(--color-border);
    white-space: nowrap;
    max-width: 200px;
    overflow: hidden;
    text-overflow: ellipsis;
}

.preview-table th {
    background: var(--color-accent-light);
    font-weight: 600;
    color: var(--color-accent);
    position: sticky;
    top: 0;
    z-index: 1;
}

.preview-table tr:hover td {
    background: var(--color-accent-light);
}

/* — Result Section — */
.result-section {
    margin-bottom: var(--space-lg);
}

.result-area {
    max-height: 400px;
    overflow: auto;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    background: var(--color-bg);
}

.result-code {
    font-family: var(--font-mono);
    font-size: var(--font-size-sm);
    line-height: 1.6;
    padding: var(--space-md);
    margin: 0;
    white-space: pre-wrap;
    word-break: break-word;
    color: var(--color-text);
}

/* — Error Area — */
.error-area {
    background: var(--color-error-bg);
    color: var(--color-error);
    padding: var(--space-md);
    border-radius: var(--radius-md);
    font-size: var(--font-size-sm);
    font-weight: 500;
    margin-top: var(--space-md);
    border: 1px solid var(--color-error);
}

/* ─── 7. Sticky Donate ────────────────────────────────────────────── */
.sticky-donate {
    position: fixed;
    bottom: calc(var(--footer-height) + var(--space-md));
    right: var(--space-md);
    z-index: 90;
    display: inline-flex;
    align-items: center;
    gap: var(--space-sm);
    padding: var(--space-sm) var(--space-lg);
    background: var(--donate-bg);
    color: var(--donate-color);
    font-weight: 700;
    font-size: var(--font-size-sm);
    border-radius: var(--radius-pill);
    box-shadow: var(--shadow-md);
    text-decoration: none;
    cursor: pointer;
    transition: transform var(--transition), box-shadow var(--transition);
}

.sticky-donate:hover {
    text-decoration: none;
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.sticky-donate:focus-visible {
    outline: 2px solid var(--donate-color);
    outline-offset: 2px;
}

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

/* ─── 8. Modal ─────────────────────────────────────────────────────── */
.modal-overlay {
    position: fixed;
    inset: 0;
    z-index: 10000;
    background: rgba(0, 0, 0, 0.55);
    display: flex;
    align-items: center;
    justify-content: center;
    padding: var(--space-md);
}

.modal-container {
    background: var(--color-surface);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    width: 100%;
    max-width: 640px;
    max-height: 85vh;
    position: relative;
    display: flex;
    flex-direction: column;
}

.modal-close {
    position: absolute;
    top: var(--space-sm);
    right: var(--space-sm);
    width: 36px;
    height: 36px;
    border: none;
    background: transparent;
    color: var(--color-text-secondary);
    font-size: 1.5rem;
    cursor: pointer;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: background var(--transition);
    z-index: 1;
}

.modal-close:hover {
    background: var(--color-bg);
}

.modal-close:focus-visible {
    outline: 2px solid var(--color-accent);
    outline-offset: 2px;
}

.modal-content {
    padding: var(--space-xl);
    overflow-y: auto;
    color: var(--color-text);
    line-height: 1.7;
}

.modal-loading {
    text-align: center;
    padding: var(--space-2xl);
    color: var(--color-text-secondary);
    font-style: italic;
}

.modal-error {
    text-align: center;
    padding: var(--space-2xl);
    color: var(--color-error);
    font-weight: 500;
}

/* ─── 9. Animations ───────────────────────────────────────────────── */
.drop-zone,
.btn,
.lang-pill,
.theme-toggle,
.sticky-donate {
    transition: all var(--transition);
}

.modal-overlay {
    animation: fadeIn 0.2s ease;
}

.modal-container {
    animation: slideUp 0.25s ease;
}

@keyframes fadeIn {
    from { opacity: 0; }
    to   { opacity: 1; }
}

@keyframes slideUp {
    from { opacity: 0; transform: translateY(16px); }
    to   { opacity: 1; transform: translateY(0); }
}

/* ─── 10. Responsive (@media max-width:640px) ─────────────────────── */
@media (max-width: 640px) {
    :root {
        --header-height: 50px;
        --container-max: 100%;
    }

    body {
        padding-top: calc(var(--header-height) + var(--banner-height) + var(--space-sm));
        padding-bottom: calc(var(--footer-height) + 64px + var(--space-md));
    }

    .tool-card {
        padding: var(--space-md);
        border-radius: var(--radius-md);
    }

    .tool-title {
        font-size: var(--font-size-xl);
    }

    .direction-toggle {
        flex-wrap: wrap;
        gap: var(--space-sm);
        font-size: var(--font-size-xs);
    }

    .toggle-switch {
        width: 44px;
        height: 24px;
    }

    .toggle-slider::before {
        height: 18px;
        width: 18px;
    }

    .toggle-switch input:checked + .toggle-slider::before {
        transform: translateX(20px);
    }

    .settings-row {
        flex-direction: column;
        gap: var(--space-md);
    }

    .setting-group {
        min-width: 100%;
    }

    .action-row {
        flex-direction: column;
    }

    .action-row .btn {
        width: 100%;
    }

    .example-row {
        flex-direction: column;
    }

    .example-row .btn {
        width: 100%;
    }

    .drop-zone {
        padding: var(--space-lg) var(--space-md);
    }

    .drop-zone-icon {
        font-size: 2rem;
    }

    .preview-table th,
    .preview-table td {
        font-size: var(--font-size-xs);
        padding: 2px var(--space-xs);
        max-width: 120px;
    }

    .header-inner {
        padding: 0 var(--space-sm);
    }

    .logo-text {
        font-size: var(--font-size-base);
    }

    .sticky-donate {
        right: var(--space-sm);
        bottom: calc(var(--footer-height) + var(--space-sm));
        padding: var(--space-xs) var(--space-md);
        font-size: var(--font-size-xs);
    }

    .modal-container {
        max-width: 100%;
        max-height: 90vh;
    }

    .modal-content {
        padding: var(--space-md);
    }
}

/* ─── 11. Reduced Motion ──────────────────────────────────────────── */
@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

/* ─── 12. Print ───────────────────────────────────────────────────── */
@media print {
    .site-header,
    .subsite-banner,
    .sticky-donate,
    .legal-footer,
    .direction-toggle,
    .action-row,
    .example-row,
    .settings-row,
    .drop-zone,
    .file-info,
    .btn {
        display: none !important;
    }

    body {
        padding: 0;
        background: #fff;
        color: #000;
    }

    .tool-card {
        border: none;
        box-shadow: none;
        padding: 0;
    }

    .preview-area,
    .result-area {
        max-height: none;
        overflow: visible;
        border: 1px solid #ccc;
    }
}