body { font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif; background: #f0f2f5; display: flex; justify-content: center; align-items: center; height: 100vh; margin: 0; }
.auth-card { background: white; padding: 2rem; border-radius: 8px; box-shadow: 0 2px 10px rgba(0,0,0,0.1); width: 100%; max-width: 350px; }
.auth-card h2 { text-align: center; color: #075e54; margin-bottom: 1.5rem; }
.form-group { margin-bottom: 1rem; }
.form-group label { display: block; margin-bottom: 5px; font-size: 14px; }
.form-group input { width: 100%; padding: 10px; border: 1px solid #ddd; border-radius: 5px; box-sizing: border-box; }
.btn-auth { width: 100%; padding: 10px; background: #25d366; border: none; color: white; border-radius: 5px; cursor: pointer; font-weight: bold; }
.btn-auth:hover { background: #128c7e; }
.auth-link { text-align: center; margin-top: 1rem; font-size: 14px; }
.auth-link a { color: #34b7f1; text-decoration: none; }



/* Reset & Base */
* { margin: 0; padding: 0; box-sizing: border-box; }

/* Mobile Container */
.app-container {
    display: flex;
    flex-direction: column;
    height: 100vh;
    width: 100%;
}

/* Header */
.app-header {
    background: #075e54;
    color: white;
    padding: 15px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    position: sticky;
    top: 0;
    z-index: 10;
}

/* Tab/View Logic */
.view { display: none; height: 100%; flex-direction: column; }
.view.active { display: flex; }

/* Contact List View */
.contact-list {
    flex: 1;
    overflow-y: auto;
    background: #fff;
}
.contact-item {
    padding: 15px;
    border-bottom: 1px solid #eee;
    display: flex;
    align-items: center;
    cursor: pointer;
}
.contact-item:active { background: #f0f0f0; }

/* Chat Room View */
.chat-room {
    position: fixed;
    top: 0; left: 0;
    width: 100%; height: 100%;
    background: #e5ddd5;
    z-index: 20;
}

.messages-display {
    flex: 1;
    padding: 15px;
    overflow-y: auto;
    display: flex;
    flex-direction: column;
}

/* Input Area Mobile */
.chat-input-area {
    background: #f0f0f0;
    padding: 10px;
    display: flex;
    gap: 10px;
    align-items: center;
}
.chat-input-area input {
    flex: 1;
    padding: 12px;
    border-radius: 25px;
    border: none;
    outline: none;
}

/* Floating Action Button (Tambah Teman) */
.fab {
    position: fixed;
    bottom: 20px;
    right: 20px;
    background: #25d366;
    color: white;
    width: 56px;
    height: 56px;
    border-radius: 50%;
    display: flex;
    justify-content: center;
    align-items: center;
    box-shadow: 0 4px 10px rgba(0,0,0,0.3);
    text-decoration: none;
    font-size: 24px;
}