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

:root{
    --bg:rgb(255,255,255);
    --bg-secondary:rgb(245,245,247);
    --bg-tertiary:rgb(232,232,237);
    --text:rgb(29,29,31);
    --text-secondary:rgb(110,110,115);
    --border:rgb(210,210,215);
    --accent:rgb(0,122,255);
    --accent-hover:rgb(0,100,220);
    --success:rgb(40,167,69);
    --error:rgb(220,53,69);
    --warning:rgb(255,149,0);
    --card-bg:rgb(255,255,255);
    --card-shadow:0 1px 3px rgba(0,0,0,.08),0 1px 2px rgba(0,0,0,.06);
    --card-shadow-hover:0 4px 12px rgba(0,0,0,.1);
    --input-bg:rgb(255,255,255);
    --input-border:rgb(210,210,215);
    --code-bg:rgb(245,245,247);
    --gutter-bg:rgb(245,245,247);
    --gutter-text:rgb(180,180,185);
    --gutter-active:rgb(80,80,85);
    --error-line-bg:rgba(220,53,69,.08);
    --error-gutter:rgb(220,53,69);
    --radius:12px;
    --radius-sm:8px;
    --transition:0.2s ease;
    --font:-apple-system,BlinkMacSystemFont,"SF Pro Text","Segoe UI",Roboto,Helvetica,Arial,sans-serif;
    --font-mono:"SF Mono","Fira Code","Cascadia Code",Consolas,monospace;
    --line-height:1.6;
    --editor-font-size:.8125rem;
    --gutter-width:48px;
}

[data-theme="dark"]{
    --bg:rgb(0,0,0);
    --bg-secondary:rgb(28,28,30);
    --bg-tertiary:rgb(44,44,46);
    --text:rgb(245,245,247);
    --text-secondary:rgb(142,142,147);
    --border:rgb(58,58,60);
    --accent:rgb(10,132,255);
    --accent-hover:rgb(64,156,255);
    --success:rgb(48,209,88);
    --error:rgb(255,69,58);
    --warning:rgb(255,159,10);
    --card-bg:rgb(28,28,30);
    --card-shadow:0 1px 3px rgba(0,0,0,.3);
    --card-shadow-hover:0 4px 12px rgba(0,0,0,.4);
    --input-bg:rgb(44,44,46);
    --input-border:rgb(58,58,60);
    --code-bg:rgb(44,44,46);
    --gutter-bg:rgb(34,34,36);
    --gutter-text:rgb(90,90,95);
    --gutter-active:rgb(180,180,185);
    --error-line-bg:rgba(255,69,58,.1);
    --error-gutter:rgb(255,69,58);
}

html{font-size:16px;-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale}
body{font-family:var(--font);background:var(--bg);color:var(--text);line-height:1.5;min-height:100vh;display:flex;flex-direction:column;transition:background var(--transition),color var(--transition)}

/* Header */
.header{position:sticky;top:0;z-index:100;background:rgba(255,255,255,.8);backdrop-filter:saturate(180%) blur(20px);-webkit-backdrop-filter:saturate(180%) blur(20px);border-bottom:1px solid var(--border);transition:background var(--transition),border-color var(--transition)}
[data-theme="dark"] .header{background:rgba(0,0,0,.8)}
.header-content{max-width:960px;margin:0 auto;padding:12px 24px;display:flex;align-items:center;justify-content:space-between}
.logo{display:flex;align-items:center;gap:10px;color:var(--text);text-decoration:none}
.logo-icon{color:var(--accent)}
.logo-text{font-size:1.125rem;font-weight:600;letter-spacing:-.02em}

.theme-toggle{background:var(--bg-secondary);border:1px solid var(--border);border-radius:50%;width:36px;height:36px;display:flex;align-items:center;justify-content:center;cursor:pointer;color:var(--text);transition:all var(--transition)}
.theme-toggle:hover{background:var(--bg-tertiary);transform:scale(1.05)}
.icon-moon{display:none}
[data-theme="dark"] .icon-sun{display:none}
[data-theme="dark"] .icon-moon{display:block}

/* Main */
.main{flex:1;max-width:960px;width:100%;margin:0 auto;padding:32px 24px}

/* Tabs */
.tabs{display:flex;gap:4px;background:var(--bg-secondary);padding:4px;border-radius:var(--radius);margin-bottom:24px}
.tab{flex:1;padding:10px 16px;border:none;background:transparent;color:var(--text-secondary);font-family:var(--font);font-size:.875rem;font-weight:500;border-radius:var(--radius-sm);cursor:pointer;transition:all var(--transition);white-space:nowrap}
.tab:hover{color:var(--text)}
.tab.active{background:var(--card-bg);color:var(--text);box-shadow:0 1px 3px rgba(0,0,0,.08)}
[data-theme="dark"] .tab.active{box-shadow:0 1px 3px rgba(0,0,0,.3)}

/* Tab panels */
.tab-panel{display:none}
.tab-panel.active{display:block}

/* Inputs */
.input-label{display:block;font-size:.8125rem;font-weight:500;color:var(--text-secondary);margin-bottom:6px;margin-top:16px}
.input-label:first-child{margin-top:0}

/* Editor with line numbers */
.editor-wrapper{position:relative;border:1px solid var(--input-border);border-radius:var(--radius-sm);overflow:hidden;transition:border-color var(--transition),box-shadow var(--transition);background:var(--input-bg)}
.editor-wrapper:focus-within{border-color:var(--accent);box-shadow:0 0 0 3px rgba(0,122,255,.15)}
.editor-readonly{background:var(--code-bg);margin-top:12px}

.line-numbers{position:absolute;top:0;left:0;width:var(--gutter-width);height:100%;background:var(--gutter-bg);border-right:1px solid var(--border);overflow:hidden;z-index:2;user-select:none;-webkit-user-select:none;transition:background var(--transition),border-color var(--transition)}
.line-numbers .ln{display:block;padding:0 8px 0 0;text-align:right;font-family:var(--font-mono);font-size:var(--editor-font-size);line-height:var(--line-height);color:var(--gutter-text);height:calc(var(--editor-font-size) * var(--line-height));transition:color .1s}
.line-numbers .ln.active{color:var(--gutter-active);font-weight:600}
.line-numbers .ln.error-line{color:var(--error-gutter);font-weight:700;background:var(--error-line-bg)}

.editor-highlight{position:absolute;top:0;left:var(--gutter-width);right:0;height:100%;overflow:hidden;pointer-events:none;z-index:1}
.editor-highlight .hl-line{display:block;width:100%;font-size:var(--editor-font-size);line-height:var(--line-height);height:calc(var(--editor-font-size) * var(--line-height))}
.editor-highlight .hl-line.error-line{background:var(--error-line-bg)}

.xml-input{width:100%;min-height:200px;padding:16px 16px 16px calc(var(--gutter-width) + 12px);border:none;border-radius:0;background:transparent;color:var(--text);font-family:var(--font-mono);font-size:var(--editor-font-size);line-height:var(--line-height);resize:vertical;outline:none;position:relative;z-index:3;white-space:pre;overflow-x:auto}
.xml-output{background:transparent;min-height:160px}

.editor-status{display:flex;justify-content:flex-end;padding:4px 12px;font-size:.6875rem;color:var(--text-secondary);font-family:var(--font-mono);letter-spacing:.02em}

.text-input,.select-input{width:100%;padding:10px 14px;border:1px solid var(--input-border);border-radius:var(--radius-sm);background:var(--input-bg);color:var(--text);font-family:var(--font);font-size:.875rem;transition:all var(--transition);outline:none}
.text-input:focus,.select-input:focus{border-color:var(--accent);box-shadow:0 0 0 3px rgba(0,122,255,.15)}
.select-input{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='%236e6e73' d='M6 8L1 3h10z'/%3E%3C/svg%3E");background-repeat:no-repeat;background-position:right 12px center;padding-right:36px}

/* Headers section */
.headers-section{margin-top:16px}
.headers-header{display:flex;align-items:center;justify-content:space-between;margin-bottom:8px}
.headers-header .input-label{margin:0}
.header-row{display:flex;gap:8px;margin-bottom:8px;align-items:center}
.header-row .text-input{flex:1}
.header-row .btn-remove{flex-shrink:0;width:32px;height:38px;padding:0;display:flex;align-items:center;justify-content:center;background:transparent;border:1px solid var(--border);border-radius:var(--radius-sm);color:var(--error);cursor:pointer;font-size:1.125rem;transition:all var(--transition)}
.header-row .btn-remove:hover{background:rgba(220,53,69,.1)}

/* Buttons */
.actions{display:flex;gap:8px;margin-top:16px;flex-wrap:wrap}

.btn{padding:10px 20px;border:none;border-radius:var(--radius-sm);font-family:var(--font);font-size:.875rem;font-weight:500;cursor:pointer;transition:all var(--transition);display:inline-flex;align-items:center;gap:6px;white-space:nowrap}
.btn:active{transform:scale(.97)}

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

.btn-secondary{background:var(--bg-secondary);color:var(--text);border:1px solid var(--border)}
.btn-secondary:hover{background:var(--bg-tertiary)}

.btn-small{padding:6px 12px;font-size:.75rem;border-radius:6px;background:var(--bg-secondary);color:var(--text-secondary);border:1px solid var(--border);cursor:pointer;transition:all var(--transition)}
.btn-small:hover{background:var(--bg-tertiary);color:var(--text)}

.btn-danger{color:var(--error);border-color:var(--error)}
.btn-danger:hover{background:rgba(220,53,69,.1)}

/* Results */
.result{margin-top:16px;padding:14px 18px;border-radius:var(--radius-sm);font-size:.875rem;display:none;animation:fadeIn .2s ease}
.result.visible{display:flex;align-items:flex-start;gap:10px}
.result.success{background:rgba(40,167,69,.08);border:1px solid rgba(40,167,69,.2);color:var(--success)}
.result.error{background:rgba(220,53,69,.08);border:1px solid rgba(220,53,69,.2);color:var(--error)}
.result.info{background:rgba(0,122,255,.08);border:1px solid rgba(0,122,255,.2);color:var(--accent)}
[data-theme="dark"] .result.success{background:rgba(48,209,88,.1);border-color:rgba(48,209,88,.25)}
[data-theme="dark"] .result.error{background:rgba(255,69,58,.1);border-color:rgba(255,69,58,.25)}
[data-theme="dark"] .result.info{background:rgba(10,132,255,.1);border-color:rgba(10,132,255,.25)}

.result-icon{font-size:1.125rem;flex-shrink:0;line-height:1.4}
.result-text{flex:1;line-height:1.5;word-break:break-word}

/* Response section */
.response-section{margin-top:16px}
.response-meta{font-size:.8125rem;color:var(--text-secondary);margin-bottom:8px;display:flex;gap:16px;flex-wrap:wrap}
.response-meta .badge{display:inline-flex;align-items:center;padding:3px 10px;border-radius:20px;font-weight:500;font-size:.75rem}
.badge-success{background:rgba(40,167,69,.1);color:var(--success)}
.badge-error{background:rgba(220,53,69,.1);color:var(--error)}
.badge-warning{background:rgba(255,149,0,.1);color:var(--warning)}
[data-theme="dark"] .badge-success{background:rgba(48,209,88,.15)}
[data-theme="dark"] .badge-error{background:rgba(255,69,58,.15)}
[data-theme="dark"] .badge-warning{background:rgba(255,159,10,.15)}

/* History */
.history-section{margin-top:48px}
.history-header{display:flex;align-items:center;justify-content:space-between;margin-bottom:16px}
.history-title{font-size:1.125rem;font-weight:600;letter-spacing:-.01em}
.history-list{display:flex;flex-direction:column;gap:8px}
.history-empty{color:var(--text-secondary);font-size:.875rem;text-align:center;padding:32px 0}

.history-item{background:var(--card-bg);border:1px solid var(--border);border-radius:var(--radius-sm);padding:14px 18px;cursor:pointer;transition:all var(--transition);display:flex;align-items:center;gap:14px}
.history-item:hover{box-shadow:var(--card-shadow-hover);border-color:var(--accent)}
.history-badge{font-size:.6875rem;font-weight:600;text-transform:uppercase;letter-spacing:.04em;padding:3px 8px;border-radius:6px;flex-shrink:0;background:var(--bg-secondary);color:var(--text-secondary)}
.history-badge.validate{background:rgba(0,122,255,.1);color:var(--accent)}
.history-badge.format{background:rgba(40,167,69,.1);color:var(--success)}
.history-badge.send{background:rgba(255,149,0,.1);color:var(--warning)}
[data-theme="dark"] .history-badge.validate{background:rgba(10,132,255,.15)}
[data-theme="dark"] .history-badge.format{background:rgba(48,209,88,.15)}
[data-theme="dark"] .history-badge.send{background:rgba(255,159,10,.15)}
.history-body{flex:1;min-width:0}
.history-preview{font-family:var(--font-mono);font-size:.75rem;color:var(--text);white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.history-time{font-size:.6875rem;color:var(--text-secondary);margin-top:2px}
.history-delete{flex-shrink:0;width:28px;height:28px;border:none;background:transparent;color:var(--text-secondary);cursor:pointer;border-radius:6px;display:flex;align-items:center;justify-content:center;font-size:1rem;transition:all var(--transition);opacity:0}
.history-item:hover .history-delete{opacity:1}
.history-delete:hover{background:rgba(220,53,69,.1);color:var(--error)}

/* Ad banner */
.ad-banner{max-width:960px;width:100%;margin:0 auto;padding:0 24px 24px}

/* Footer */
.footer{border-top:1px solid var(--border);background:var(--bg-secondary);transition:all var(--transition)}
.footer-content{max-width:960px;margin:0 auto;padding:20px 24px;display:flex;align-items:center;justify-content:space-between;flex-wrap:wrap;gap:12px}
.footer-copy{font-size:.8125rem;color:var(--text-secondary)}
.footer-links{display:flex;gap:20px}
.footer-links a{font-size:.8125rem;color:var(--text-secondary);text-decoration:none;transition:color var(--transition)}
.footer-links a:hover{color:var(--accent)}

/* Loading spinner */
.spinner{display:inline-block;width:16px;height:16px;border:2px solid rgba(255,255,255,.3);border-top-color:#fff;border-radius:50%;animation:spin .6s linear infinite}
.btn-secondary .spinner{border:2px solid var(--border);border-top-color:var(--text)}

@keyframes spin{to{transform:rotate(360deg)}}
@keyframes fadeIn{from{opacity:0;transform:translateY(-4px)}to{opacity:1;transform:translateY(0)}}

/* Responsive */
@media(max-width:640px){
    :root{--gutter-width:36px}
    .header-content{padding:10px 16px}
    .main{padding:20px 16px}
    .tabs{gap:2px}
    .tab{padding:8px 10px;font-size:.8125rem}
    .xml-input{min-height:150px;padding:12px 12px 12px calc(var(--gutter-width) + 8px);font-size:.75rem}
    .actions{gap:6px}
    .btn{padding:8px 14px;font-size:.8125rem}
    .footer-content{flex-direction:column;text-align:center;padding:16px}
    .ad-banner{padding:0 16px 16px}
    .history-item{padding:10px 14px}
    .header-row{flex-direction:column}
    .header-row .text-input{width:100%}
}

@media(max-width:400px){
    .logo-text{font-size:1rem}
    .tabs{flex-direction:column}
    .tab{text-align:center}
}