:root {
    --color-white: #ffffff;
    --color-black: #181818;
    --color-blue: #00b3d3;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background-color: var(--color-white);
    color: var(--color-black);
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 2rem;
}

.container {
    max-width: 600px;
    width: 100%;
    text-align: center;
}

h1 {
    font-size: 2.5rem;
    margin-bottom: 0.5rem;
    font-weight: 700;
    color: var(--color-black);
}

.highlight {
    color: var(--color-blue);
}

.subtitle {
    font-size: 1.1rem;
    color: var(--color-black);
    margin-bottom: 3rem;
    opacity: 0.8;
}

.shortener-box {
    background: var(--color-white);
    border-radius: 16px;
    padding: 2.5rem;
}

.input-group {
    display: flex;
    gap: 0.75rem;
    margin-bottom: 1.5rem;
}

input[type="url"] {
    flex: 1;
    padding: 1rem 1.25rem;
    border: 2px solid var(--color-black);
    border-radius: 12px;
    font-size: 1rem;
    outline: none;
    background-color: var(--color-white);
    color: var(--color-black);
    text-align: center;
}

input[type="url"]:focus {
    background-color: var(--color-white);
    filter: brightness(0.95);
}

input[type="url"]::placeholder {
    color: var(--color-black);
    opacity: 0.6;
}

.btn-shorten {
    padding: 1rem 2rem;
    background-color: var(--color-blue);
    color: var(--color-white);
    border: none;
    border-radius: 12px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: background-color 0.2s;
}

.btn-shorten:hover {
    background-color: var(--color-blue);
    filter: brightness(0.9);
}

.btn-shorten:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

.result-box {
    background-color: var(--color-white);
    border: 2px solid var(--color-blue);
    border-radius: 12px;
    padding: 1.25rem 1.5rem;
    margin-top: 1.5rem;
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    gap: 1.5rem;
}

.shortened-url {
    font-size: 1.1rem;
    color: var(--color-blue);
    font-weight: 600;
    word-break: break-all;
    text-align: center;
    flex: 1;
}

.btn-copy {
    padding: 0.75rem 1.5rem;
    background-color: var(--color-black);
    color: var(--color-white);
    border: none;
    border-radius: 8px;
    font-size: 0.95rem;
    font-weight: 600;
    cursor: pointer;
    transition: filter 0.2s;
    white-space: nowrap;
    align-self: flex-start;
}

.btn-copy:hover {
    filter: brightness(1.3);
}

.error-message {
    background-color: #ffebee;
    border: 2px solid #ef5350;
    border-radius: 12px;
    padding: 1rem;
    margin-top: 1rem;
    color: #c62828;
    text-align: center;
}

@media (max-width: 768px) {
    h1 {
        font-size: 2rem;
    }

    .input-group {
        flex-direction: column;
    }

    .shortener-box {
        padding: 1.5rem;
    }

    .result-box {
        flex-direction: column;
        text-align: center;
    }

    .shortened-url {
        text-align: center;
    }

    .btn-copy {
        align-self: center;
    }
}