/* CSS Variables for Theming */
:root {
    --bg-color: #f3f4f6;
    --surface-color: #ffffff;
    --surface-border: rgba(0, 0, 0, 0.1);
    --text-primary: #1f2937;
    --text-secondary: #4b5563;
    --primary-color: #3b82f6;
    --primary-hover: #2563eb;
    --error-color: #ef4444;
    --success-color: #10b981;
    --border-color: #e5e7eb;
    --pane-header-bg: rgba(0, 0, 0, 0.02);

    /* XML Syntax Highlighting - Light */
    --xml-tag: #0284c7;
    --xml-attr: #ea580c;
    --xml-string: #16a34a;
    --xml-text: #1f2937;
    --xml-comment: #64748b;
    --xml-cdata: #9333ea;
    --xml-bracket: #475569;

    --font-sans: 'Inter', sans-serif;
    --font-mono: 'Fira Code', monospace;
    --radius-lg: 16px;
    --radius-md: 8px;
    --shadow-glass: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
}

body.dark-theme {
    --bg-color: #0f172a;
    --surface-color: #1e293b;
    --surface-border: rgba(255, 255, 255, 0.1);
    --text-primary: #f8fafc;
    --text-secondary: #cbd5e1;
    --border-color: #334155;
    --pane-header-bg: rgba(255, 255, 255, 0.03);

    /* XML Syntax Highlighting - Dark */
    --xml-tag: #38bdf8;
    --xml-attr: #fb923c;
    --xml-string: #4ade80;
    --xml-text: #f8fafc;
    --xml-comment: #94a3b8;
    --xml-cdata: #c084fc;
    --xml-bracket: #94a3b8;

    --shadow-glass: 0 4px 6px -1px rgba(0, 0, 0, 0.5), 0 2px 4px -1px rgba(0, 0, 0, 0.3);
}

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

body {
    font-family: var(--font-sans);
    background-color: var(--bg-color);
    color: var(--text-primary);
    min-height: 100vh;
    transition: background-color 0.3s ease, color 0.3s ease;
    overflow: hidden;
    position: relative;
}

body::before {
    display: none;
}

.app-wrapper {
    display: flex;
    flex-direction: column;
    height: 100vh;
    padding: 1rem 2rem;
    max-width: 1800px;
    margin: 0 auto;
}

header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.25rem 0;
    margin-bottom: 0.5rem;
}

.logo {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.logo-icon-img {
    width: 38px;
    height: 38px;
    border-radius: var(--radius-md);
    display: block;
}

.logo-icon {
    font-family: var(--font-mono);
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
    background: rgba(59, 130, 246, 0.1);
    padding: 0.25rem 0.75rem;
    border-radius: var(--radius-md);
}

h1 {
    font-size: 1.5rem;
    font-weight: 700;
    letter-spacing: -0.025em;
    background: linear-gradient(135deg, var(--text-primary), var(--primary-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.theme-toggle {
    background: var(--surface-color);
    border: 1px solid var(--surface-border);
    border-radius: 50px;
    padding: 0.5rem 1rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 1.25rem;
    transition: all 0.3s ease;
    color: var(--text-primary);
}

.theme-toggle:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

body.dark-theme .icon-sun { display: none; }
body:not(.dark-theme) .icon-moon { display: none; }

.split-container {
    display: flex;
    flex: 1;
    min-height: 0;
    gap: 0.5rem;
    padding-bottom: 1rem;
}

.pane {
    flex: 1;
    display: flex;
    flex-direction: column;
    background: var(--surface-color);
    border: 1px solid var(--surface-border);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-glass);
    overflow: hidden;
    transition: all 0.3s ease;
}

.pane-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.5rem 1rem;
    border-bottom: 1px solid var(--border-color);
    background: var(--pane-header-bg);
}

.pane h2 {
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-secondary);
    display: inline-flex;
    align-items: center;
    gap: 0.4rem;
}

.pane-collapse-btn {
    background: transparent;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    padding: 2px;
    display: none;
    align-items: center;
    justify-content: center;
    border-radius: 4px;
    transition: transform 0.2s ease, color 0.2s ease, background 0.2s ease;
}

@media (max-width: 768px) {
    .pane-collapse-btn {
        display: inline-flex;
    }
}

.pane-collapse-btn:hover {
    color: var(--primary-color);
    background: rgba(59, 130, 246, 0.1);
}

textarea#xml-input {
    flex: 1;
    width: 100%;
    resize: none;
    padding: 1.5rem;
    border: none;
    background: transparent;
    color: var(--text-primary);
    font-family: var(--font-mono);
    font-size: 0.9rem;
    line-height: 1.6;
    outline: none;
}

.xml-viewer {
    flex: 1;
    padding: 1.5rem;
    overflow-y: auto;
    font-family: var(--font-mono);
    font-size: 0.9rem;
    line-height: 1.6;
}

/* Status Indicator */
#status-indicator {
    font-size: 0.8rem;
    font-weight: 600;
    padding: 0.25rem 0.75rem;
    border-radius: 50px;
    opacity: 0;
    transition: opacity 0.3s, background-color 0.3s, color 0.3s;
}

#status-indicator.visible {
    opacity: 1;
}

#status-indicator.valid {
    background: rgba(16, 185, 129, 0.1);
    color: var(--success-color);
}

#status-indicator.invalid {
    background: rgba(239, 68, 68, 0.1);
    color: var(--error-color);
}

.placeholder {
    color: var(--text-secondary);
    text-align: center;
    margin-top: 2rem;
    font-style: italic;
}

.error-message {
    color: var(--error-color);
    background: rgba(239, 68, 68, 0.05);
    padding: 1rem;
    border-radius: var(--radius-md);
    border-left: 4px solid var(--error-color);
    white-space: pre-wrap;
    word-break: break-all;
}

.error-message .error-loc {
    display: inline-block;
    font-family: var(--font-mono);
    font-size: 0.8rem;
    background: rgba(239, 68, 68, 0.15);
    padding: 0.1rem 0.5rem;
    border-radius: 4px;
    margin-bottom: 0.5rem;
}

/* Drop overlay */
.left-pane {
    position: relative;
}

.drop-overlay {
    position: absolute;
    inset: 0;
    display: none;
    align-items: center;
    justify-content: center;
    background: rgba(59, 130, 246, 0.12);
    border: 2px dashed var(--primary-color);
    border-radius: var(--radius-lg);
    color: var(--primary-color);
    font-weight: 600;
    font-size: 1.1rem;
    pointer-events: none;
    z-index: 10;
}

.left-pane.dragover .drop-overlay {
    display: flex;
}

/* Buttons */
.actions {
    display: flex;
    gap: 0.5rem;
}

.action-btn {
    background: transparent;
    border: 1px solid var(--border-color);
    color: var(--text-secondary);
    padding: 0.25rem 0.75rem;
    border-radius: var(--radius-md);
    font-size: 0.8rem;
    cursor: pointer;
    transition: all 0.2s ease;
    font-family: var(--font-sans);
    font-weight: 500;
    display: inline-flex;
    align-items: center;
    gap: 0.35rem;
}

.action-btn:hover {
    background: var(--border-color);
    color: var(--text-primary);
}

/* XML Tree Styles */
.xml-node {
    margin-left: 1.5rem;
    position: relative;
}

.xml-line {
    display: block;
    padding: 2px 0;
    white-space: nowrap;
}

.toggler {
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 16px;
    height: 16px;
    margin-right: 4px;
    margin-left: -20px;
    color: var(--text-secondary);
    transition: transform 0.2s ease;
    user-select: none;
    font-size: 0.7rem;
}

.toggler:hover {
    color: var(--primary-color);
}

.toggler.collapsed {
    transform: rotate(-90deg);
}

.xml-tag     { color: var(--xml-tag); font-weight: 500; }
.xml-attr    { color: var(--xml-attr); font-style: italic; }
.xml-string  { color: var(--xml-string); }
.xml-text    { color: var(--xml-text); }
.xml-comment { color: var(--xml-comment); font-style: italic; }
.xml-cdata   { color: var(--xml-cdata); }
.xml-bracket { color: var(--xml-bracket); font-weight: 500; }

.xml-value {
    word-break: break-word;
}

.children-container.collapsed {
    display: none;
}

.collapsed-text {
    color: var(--text-secondary);
    font-style: italic;
    cursor: pointer;
    background: rgba(0, 0, 0, 0.05);
    padding: 0 6px;
    border-radius: 4px;
    margin: 0 4px;
    font-size: 0.85em;
    user-select: none;
}

body.dark-theme .collapsed-text {
    background: rgba(255, 255, 255, 0.1);
}

.collapsed-text:hover {
    background: rgba(59, 130, 246, 0.2);
    color: var(--primary-color);
}

/* Inline editing */
.editable {
    outline: none;
    border-radius: 3px;
    padding: 0 2px;
    margin: 0 -2px;
    transition: background 0.15s ease, box-shadow 0.15s ease;
}

body:not(.edit-mode) .editable {
    -webkit-user-modify: read-only;
    -moz-user-modify: read-only;
    user-modify: read-only;
    caret-color: transparent;
}

body.edit-mode .editable {
    cursor: text;
    -webkit-user-modify: read-write-plaintext-only;
}

body.edit-mode .editable:hover {
    background: rgba(59, 130, 246, 0.08);
}

body.edit-mode .editable:focus {
    background: rgba(59, 130, 246, 0.15);
    box-shadow: 0 0 0 1px var(--primary-color);
}

.editable.edit-error {
    background: rgba(239, 68, 68, 0.2);
    box-shadow: 0 0 0 1px var(--error-color);
}

body.edit-mode .xml-viewer {
    background: rgba(59, 130, 246, 0.02);
}

.viewer-wrap {
    position: relative;
    flex: 1;
    min-height: 0;
    display: flex;
    flex-direction: column;
}

.edit-floating-btn {
    position: absolute;
    top: 10px;
    right: 12px;
    z-index: 5;
    width: 34px;
    height: 34px;
    border-radius: 50%;
    background: var(--surface-color);
    border: 1px solid var(--border-color);
    color: var(--text-secondary);
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    box-shadow: var(--shadow-glass);
    transition: all 0.2s ease;
}

.edit-floating-btn:hover {
    color: var(--primary-color);
    border-color: var(--primary-color);
    transform: translateY(-1px);
}

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


/* Scrollbar */
::-webkit-scrollbar {
    width: 8px;
    height: 8px;
}
::-webkit-scrollbar-track {
    background: transparent;
}
::-webkit-scrollbar-thumb {
    background: var(--border-color);
    border-radius: 4px;
}
::-webkit-scrollbar-thumb:hover {
    background: var(--text-secondary);
}

/* Footer */
.app-footer {
    text-align: center;
    padding-top: 1rem;
    font-size: 0.8rem;
    color: var(--text-secondary);
    font-weight: 500;
}

/* Responsive Design for Mobile */
@media (max-width: 768px) {
    body {
        overflow-y: auto;
    }

    .app-wrapper {
        height: auto;
        min-height: 100vh;
        padding: 1rem;
    }

    header {
        margin-bottom: 1rem;
    }

    .logo-icon {
        font-size: 1.2rem;
        padding: 0.15rem 0.5rem;
    }

    h1 {
        font-size: 1.2rem;
    }

    .theme-toggle {
        padding: 0.4rem 0.8rem;
        font-size: 1rem;
    }

    .split-container {
        flex-direction: column;
        gap: 1rem;
        height: auto;
    }

    .divider {
        display: none;
    }

    .pane {
        flex: none;
        height: 45vh;
        min-height: 350px;
    }

    .left-pane.collapsed .pane-collapse-btn {
        transform: rotate(-90deg);
    }

    .left-pane.collapsed textarea#xml-input,
    .left-pane.collapsed .drop-overlay {
        display: none;
    }

    .left-pane.collapsed {
        flex: 0 0 auto;
        min-height: 0;
        height: auto;
    }

    .split-container:has(.left-pane.collapsed) .right-pane {
        height: 80vh;
        min-height: 500px;
    }

    .pane-header {
        padding: 0.5rem 0.75rem;
        flex-direction: column;
        align-items: stretch;
        gap: 0.4rem;
    }

    .pane-header h2 {
        font-size: 0.9rem;
    }

    .pane-header .actions {
        flex-wrap: wrap;
        gap: 0.35rem;
    }

    .action-btn {
        padding: 0.25rem 0.5rem;
        font-size: 0.72rem;
        flex: 1 1 auto;
        justify-content: center;
        white-space: nowrap;
    }

    #status-indicator {
        font-size: 0.72rem;
        padding: 0.2rem 0.5rem;
    }

    textarea#xml-input {
        padding: 1rem;
    }

    .xml-viewer {
        padding: 1rem 1rem 1rem 1.5rem;
    }
}