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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Arial, sans-serif;
    background: #f0f2f5;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
    color: #333;
}

.card {
    background: #ffffff;
    border-radius: 8px;
    padding: 32px 28px;
    width: 100%;
    max-width: 380px;
    box-shadow: 0 2px 12px rgba(0, 0, 0, 0.08);
    border: 1px solid #e4e6eb;
}

h1 {
    font-size: 20px;
    font-weight: 600;
    margin-bottom: 6px;
    color: #1c1e21;
}

.subtitle {
    font-size: 14px;
    color: #65676b;
    margin-bottom: 20px;
}

.captcha-box {
    position: relative;
    background: #f5f6f7;
    border: 1px solid #e4e6eb;
    border-radius: 6px;
    padding: 18px 50px 18px 18px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 14px;
    min-height: 70px;
}

.captcha-text {
    font-family: 'Courier New', Courier, monospace;
    font-size: 32px;
    font-weight: 700;
    letter-spacing: 10px;
    color: #1c1e21;
    user-select: none;
    text-shadow: 1px 1px 0 rgba(0, 0, 0, 0.08);
}

#refreshBtn {
    position: absolute;
    right: 8px;
    bottom: 8px;
    width: 30px;
    height: 30px;
    border: none;
    background: #ffffff;
    color: #65676b;
    border-radius: 4px;
    cursor: pointer;
    font-size: 18px;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.2s ease;
    box-shadow: 0 1px 2px rgba(0, 0, 0, 0.08);
}

#refreshBtn:hover {
    background: #f0f2f5;
    color: #1c1e21;
}

#refreshBtn:active {
    transform: rotate(180deg);
}

#captchaInput {
    width: 100%;
    padding: 11px 14px;
    font-size: 15px;
    border: 1px solid #ccd0d5;
    border-radius: 6px;
    outline: none;
    transition: border-color 0.15s ease;
    letter-spacing: 1px;
    text-transform: uppercase;
    background: #ffffff;
    font-family: inherit;
}

#captchaInput::placeholder {
    text-transform: none;
    letter-spacing: normal;
    color: #8a8d91;
}

#captchaInput:focus {
    border-color: #1877f2;
}

#captchaInput.error {
    border-color: #e41e3f;
    animation: shake 0.3s ease;
}

#captchaInput.success {
    border-color: #42b72a;
}

@keyframes shake {
    0%, 100% { transform: translateX(0); }
    25% { transform: translateX(-6px); }
    75% { transform: translateX(6px); }
}

.feedback {
    min-height: 18px;
    margin-top: 8px;
    font-size: 13px;
    opacity: 0;
    transition: opacity 0.2s ease;
}

.feedback.show {
    opacity: 1;
}

.feedback.error {
    color: #e41e3f;
}

.feedback.success {
    color: #42b72a;
}

.verify-btn {
    width: 100%;
    padding: 11px 16px;
    background: #1877f2;
    color: #ffffff;
    border: none;
    border-radius: 6px;
    font-size: 15px;
    font-weight: 600;
    cursor: pointer;
    margin-top: 14px;
    transition: background 0.15s ease;
    font-family: inherit;
}

.verify-btn:hover {
    background: #166fe5;
}

.verify-btn:active {
    background: #1464d3;
}

.verify-btn:disabled {
    background: #bcc0c4;
    cursor: not-allowed;
}

.continue-btn {
    width: 100%;
    padding: 11px 16px;
    background: #42b72a;
    color: #ffffff;
    border: none;
    border-radius: 6px;
    font-size: 15px;
    font-weight: 600;
    cursor: pointer;
    margin-top: 10px;
    transition: background 0.15s ease, opacity 0.3s ease, transform 0.3s ease;
    font-family: inherit;
    display: none;
    opacity: 0;
    transform: translateY(8px);
}

.continue-btn.show {
    display: block;
    opacity: 1;
    transform: translateY(0);
}

.continue-btn:hover {
    background: #36a420;
}

.continue-btn:active {
    background: #2f9119;
}

@media (max-width: 420px) {
    .card {
        padding: 24px 20px;
    }
}