:root { color-scheme: dark; }
    input, select, textarea { color-scheme: dark; }
* { margin: 0; padding: 0; box-sizing: border-box; }
body { font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif; background: #0f172a; color: #e2e8f0; min-height: 100vh; display: flex; justify-content: center; align-items: center; }
.container { width: 100%; max-width: 520px; padding: 20px; }
.card { background: #1e293b; border-radius: 16px; padding: 32px 28px; border: 1px solid #334155; }
h1 { font-size: 24px; margin-bottom: 8px; color: #f1f5f9; }
.subtitle { color: #94a3b8; font-size: 14px; margin-bottom: 28px; }
label { display: block; font-size: 14px; color: #94a3b8; margin-bottom: 6px; font-weight: 500; }
input[type="text"] { width: 100%; padding: 12px 14px; border: 1px solid #475569; border-radius: 10px; font-size: 15px; background: #0f172a; color: #e2e8f0; outline: none; transition: border-color .2s; }
input[type="text"]:focus { border-color: #3b82f6; }
input[type="text"]::placeholder { color: #64748b; }
.input-wrap { position: relative; }
.input-wrap input { padding-right: 36px; }
.clear-btn { position: absolute; right: 10px; top: 50%; transform: translateY(-50%); width: 24px; height: 24px; border: none; background: #475569; color: #e2e8f0; border-radius: 50%; cursor: pointer; font-size: 14px; display: none; align-items: center; justify-content: center; line-height: 1; }
.clear-btn.show { display: flex; }
.clear-btn:hover { background: #64748b; }
.input-group { margin-bottom: 20px; }
.btn { width: 100%; padding: 13px; border: none; border-radius: 10px; font-size: 16px; font-weight: 600; cursor: pointer; transition: all .2s; }
.btn-primary { background: #3b82f6; color: #fff; }
.btn-primary:hover { background: #2563eb; }
.btn-primary:disabled { background: #475569; cursor: not-allowed; }
.help-btn { display: inline-flex; align-items: center; gap: 6px; padding: 8px 14px; font-size: 13px; font-weight: 600; color: #e2e8f0; background: #334155; border: 1px solid #475569; border-radius: 10px; cursor: pointer; transition: all .2s; white-space: nowrap; }
.help-btn:hover { background: #475569; color: #fff; border-color: #64748b; }
.help-btn:active { transform: scale(.96); }
.card-status { display: inline-flex; align-items: center; gap: 6px; font-size: 13px; padding: 4px 10px; border-radius: 20px; margin-top: 8px; }
.card-valid { background: #065f46; color: #6ee7b7; }
.card-invalid { background: #7f1d1d; color: #fca5a5; }
.card-checking { background: #334155; color: #94a3b8; }
.result-box { margin-top: 24px; padding: 18px; background: #0f172a; border-radius: 10px; border: 1px solid #334155; display: none; }
.result-box.show { display: block; }
.result-box .url { word-break: break-all; font-size: 14px; color: #93c5fd; margin-bottom: 12px; line-height: 1.5; }
.result-box .copy-btn { padding: 10px 20px; background: #059669; color: #fff; border: none; border-radius: 8px; cursor: pointer; font-size: 14px; font-weight: 500; transition: transform .15s, background .2s, box-shadow .2s; position: relative; overflow: hidden; }
.result-box .copy-btn:hover { background: #047857; }
.result-box .copy-btn:active { transform: scale(0.94); }
.result-box .copy-btn.copied { background: #6366f1; box-shadow: 0 0 0 4px rgba(99,102,241,.35); }
.error-box { margin-top: 16px; padding: 14px; background: #7f1d1d; border-radius: 10px; color: #fca5a5; font-size: 14px; display: none; }
.error-box.show { display: block; }
.loading { text-align: center; padding: 20px; display: none; }
.loading.show { display: block; }
.spinner { width: 40px; height: 40px; border: 3px solid #334155; border-top-color: #3b82f6; border-radius: 50%; animation: spin .8s linear infinite; margin: 0 auto 12px; }
@keyframes spin { to { transform: rotate(360deg); } }
@keyframes copyPulse { 0% { box-shadow: 0 0 0 0 rgba(99,102,241,.5); } 70% { box-shadow: 0 0 0 10px rgba(99,102,241,0); } 100% { box-shadow: 0 0 0 0 rgba(99,102,241,0); } }
.result-box .copy-btn.copied { background: #6366f1; animation: copyPulse .5s ease-out; }
.footer { text-align: center; margin-top: 24px; color: #475569; font-size: 13px; }
.footer a { color: #64748b; text-decoration: none; }
.footer a:hover { color: #94a3b8; }
.ann-toast { position: fixed; top: 16px; right: 16px; max-width: 340px; width: calc(100% - 32px); z-index: 999; background: #0f172a; border: 1px solid #334155; border-left: 4px solid #3b82f6; border-radius: 10px; padding: 14px 16px; box-shadow: 0 12px 32px rgba(0,0,0,.5); opacity: 0; transform: translateX(24px); pointer-events: none; transition: opacity .3s, transform .3s; }
.ann-toast.show { opacity: 1; transform: translateX(0); pointer-events: auto; }
.ann-toast-title { display: flex; align-items: center; justify-content: space-between; font-size: 14px; font-weight: 600; color: #e2e8f0; margin-bottom: 6px; }
.ann-toast-close { border: none; background: transparent; color: #94a3b8; font-size: 15px; cursor: pointer; padding: 0 2px; line-height: 1; }
.ann-toast-close:hover { color: #e2e8f0; }
.ann-content { font-size: 13px; line-height: 1.6; color: #cbd5e1; white-space: pre-wrap; word-break: break-word; max-height: 45vh; overflow-y: auto; }
.link-wavy { text-decoration: underline wavy #f87171 1.5px; text-underline-offset: 5px; }