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

.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
    padding: 0;
    margin: -1px;
}

body {
    font-family: "Segoe UI", "Inter", -apple-system, BlinkMacSystemFont, sans-serif;
    background: #08080d;
    color: #d0d0d8;
    min-height: 100vh;
    line-height: 1.65;
}

.container {
    max-width: 880px;
    margin: 0 auto;
    padding: 2rem 1.5rem 4rem;
}

header {
    text-align: center;
    padding: 2.5rem 0 1.8rem;
    border-bottom: 1px solid #18182a;
    margin-bottom: 2rem;
}

header h1 {
    font-size: 2.1rem;
    color: #fff;
    letter-spacing: -0.4px;
    margin-bottom: 0.4rem;
}

.subtitle {
    color: #777;
    font-size: 1.05rem;
}

.card {
    background: #0e0e16;
    border: 1px solid #1a1a2e;
    border-radius: 14px;
    padding: 1.5rem 1.6rem;
    margin-bottom: 1.5rem;
}

.card h2 {
    color: #fff;
    font-size: 1.25rem;
    margin-bottom: 1rem;
}

.card p {
    color: #b0b0bc;
    margin-bottom: 0.7rem;
}

.card code {
    background: #16162a;
    color: #7dd3fc;
    padding: 2px 7px;
    border-radius: 4px;
    font-family: "Cascadia Code", "Fira Code", "JetBrains Mono", monospace;
    font-size: 0.88em;
}

.rules {
    background: #0a0a12;
    border-radius: 10px;
    padding: 1rem 1.2rem;
    margin: 1rem 0;
}

.rules h3 {
    color: #ccc;
    font-size: 0.92rem;
    margin-bottom: 0.5rem;
}

.rules ul {
    padding-left: 1.4rem;
}

.rules li {
    color: #999;
    font-size: 0.88rem;
    margin-bottom: 0.25rem;
}

.hint {
    background: #17140a;
    border: 1px solid #3a3200;
    border-radius: 10px;
    padding: 0.9rem 1.1rem;
    margin-top: 1rem;
    color: #d4a800;
    font-size: 0.9rem;
}

#code-editor {
    display: block;
    width: 100%;
    min-height: 300px;
    background: #0a0a14;
    color: #e0e0e8;
    border: 1px solid #1a1a2e;
    border-radius: 12px;
    padding: 1.15rem 1.25rem;
    font-family: "Cascadia Code", "Fira Code", "JetBrains Mono", monospace;
    font-size: 13.5px;
    line-height: 1.65;
    tab-size: 4;
    resize: vertical;
    outline: none;
    transition: border-color 0.2s;
}

#code-editor:focus {
    border-color: #3b82f6;
}

.editor-footer {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-top: 0.8rem;
}

.shortcut {
    color: #555;
    font-size: 0.82rem;
}

#submit-btn {
    padding: 0.7rem 2.2rem;
    background: #3b82f6;
    color: #fff;
    border: none;
    border-radius: 10px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.2s, transform 0.15s;
    letter-spacing: 0.3px;
}

#submit-btn:hover:not(:disabled) {
    background: #2563eb;
    transform: translateY(-1px);
}

#submit-btn:active:not(:disabled) {
    transform: translateY(0);
}

#submit-btn:disabled {
    background: #1c2d4a;
    color: #6b8ab5;
    cursor: not-allowed;
}

.output {
    background: #0a0a14;
    border: 1px solid #1a1a2e;
    border-radius: 12px;
    padding: 1.15rem 1.25rem;
    font-family: "Cascadia Code", "Fira Code", "JetBrains Mono", monospace;
    font-size: 0.88rem;
    white-space: pre-wrap;
    word-break: break-word;
    min-height: 50px;
}

.output.loading {
    color: #7dd3fc;
    border-color: #1a2d4a;
}

.output.success {
    border-color: #166534;
    background: #091a09;
    color: #4ade80;
}

.output.error {
    border-color: #7f1d1d;
    background: #180a0a;
    color: #f87171;
}

.flag-banner {
    text-align: center;
    padding: 0.6rem 0;
}

.flag {
    display: inline-block;
    background: #14532d;
    color: #4ade80;
    padding: 0.55rem 1.6rem;
    border-radius: 8px;
    font-size: 1.15rem;
    font-weight: 700;
    letter-spacing: 0.8px;
    word-break: break-all;
}

::-webkit-scrollbar {
    width: 7px;
}

::-webkit-scrollbar-track {
    background: #08080d;
}

::-webkit-scrollbar-thumb {
    background: #252540;
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: #3a3a5e;
}

@media (max-width: 640px) {
    .container {
        padding: 1rem;
    }
    header h1 {
        font-size: 1.5rem;
    }
    #code-editor {
        min-height: 220px;
        font-size: 12px;
    }
    .editor-footer {
        flex-direction: column;
        gap: 0.6rem;
    }
    #submit-btn {
        width: 100%;
    }
}