:root {
    --wechat-green: #07c160;
    --wechat-bg: #f7f7f7;
    --wechat-header-bg: #ededed;
    --wechat-footer-bg: #f7f7f7;
    --wechat-text-black: #191919;
    --wechat-text-gray: #b2b2b2;
    --wechat-nav-gray: #333333;
}

body {
    margin: 0;
    padding: 0;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    background-color: #f0f0f0;
    color: var(--wechat-text-black);
    height: 100vh;
    display: flex;
    justify-content: center;
}

.mobile-frame {
    width: 100%;
    max-width: 500px;
    background: white;
    height: 100vh;
    display: flex;
    flex-direction: column;
    position: relative;
    box-shadow: 0 0 20px rgba(0, 0, 0, 0.1);
}

.main-header {
    height: 50px;
    background: var(--wechat-header-bg);
    color: var(--wechat-text-black);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 15px;
    border-bottom: 1px solid #ddd;
    flex-shrink: 0;
}

.header-title {
    font-weight: 500;
    font-size: 1.1rem;
}

.header-icon {
    font-size: 1.1rem;
    margin-left: 15px;
    color: #333;
    cursor: pointer;
}

.content-area {
    flex: 1;
    overflow-y: auto;
    background: var(--wechat-bg);
}

.main-footer {
    height: 60px;
    background: var(--wechat-footer-bg);
    border-top: 1px solid #ddd;
    display: flex;
    justify-content: space-around;
    align-items: center;
    flex-shrink: 0;
}

.nav-item {
    text-decoration: none;
    color: #333;
    display: flex;
    flex-direction: column;
    align-items: center;
    font-size: 0.75rem;
    transition: color 0.2s;
}

.nav-item i {
    font-size: 1.4rem;
    margin-bottom: 4px;
}

.nav-item.active {
    color: var(--wechat-green);
}

/* Chat Bubbles */
.messages-container {
    padding: 15px;
    display: flex;
    flex-direction: column;
}

.message-bubble {
    max-width: 75%;
    padding: 10px 12px;
    border-radius: 6px;
    margin-bottom: 12px;
    font-size: 1rem;
    line-height: 1.4;
    position: relative;
    word-wrap: break-word;
}

.message-received {
    align-self: flex-start;
    background: white;
    border: 1px solid #eee;
}

.message-sent {
    align-self: flex-end;
    background: #95ec69;
    border: 1px solid #82d358;
}

.input-area {
    padding: 10px 15px;
    background: #f7f7f7;
    border-top: 1px solid #ddd;
    display: flex;
    align-items: center;
}

.chat-input {
    flex: 1;
    border: 1px solid #ddd;
    border-radius: 4px;
    padding: 8px 12px;
    outline: none;
    font-size: 1rem;
    max-height: 100px;
    resize: none;
}

.btn-send {
    background: var(--wechat-green);
    color: white;
    border: none;
    padding: 8px 15px;
    border-radius: 4px;
    margin-left: 10px;
    cursor: pointer;
}

/* Auth Pages */
.auth-container {
    padding: 40px 20px;
    text-align: center;
}

.form-group {
    margin-bottom: 20px;
    text-align: left;
}

input[type="text"],
input[type="password"],
input[type="email"],
select,
textarea {
    width: 100%;
    padding: 12px;
    border: 1px solid #ddd;
    border-radius: 4px;
    box-sizing: border-box;
}

.error {
    color: #fa5151;
    font-size: 0.8rem;
    margin-top: 5px;
}