:root {
    --primary: #007bff;
    --primary-dark: #0056b3;
    --bg: #f4f7f6;
    --card-bg: #ffffff;
    --text: #333;
    --border: #ddd;
}

* { box-sizing: border-box; margin: 0; padding: 0; font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif; }
body { background-color: var(--bg); color: var(--text); padding-bottom: 2rem; }

.hidden { display: none !important; }
.mt-1 { margin-top: 1rem; }

#main-header {
    background-color: var(--card-bg);
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    margin-bottom: 2rem;
}

button {
    background: var(--primary); color: white; border: none; padding: 0.5rem 1rem;
    border-radius: 4px; cursor: pointer; transition: 0.3s;
}
button:hover { background: var(--primary-dark); }
.full-width { grid-column: 1 / -1; }

#app-container { max-width: 1000px; margin: 0 auto; padding: 0 1rem; }

.card {
    background: var(--card-bg); padding: 1.5rem; border-radius: 8px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.05); margin-bottom: 1.5rem;
}
.login-card { max-width: 400px; margin: 4rem auto; }

input {
    width: 100%; padding: 0.5rem; margin-bottom: 1rem; border: 1px solid var(--border);
    border-radius: 4px; outline: none;
}
input:focus { border-color: var(--primary); }

.grid-form { display: grid; grid-template-columns: 1fr 1fr; gap: 0.5rem 1rem; }
@media (max-width: 600px) { .grid-form { grid-template-columns: 1fr; } }

/* Tablas responsive */
.table-responsive { overflow-x: auto; background: var(--card-bg); border-radius: 8px; box-shadow: 0 2px 8px rgba(0,0,0,0.05); }
table { width: 100%; border-collapse: collapse; }
th, td { padding: 1rem; text-align: left; border-bottom: 1px solid var(--border); }
th { background-color: #fafafa; }

/* Tarjeta IMC */
.imc-card { text-align: center; background: #e9ecef; padding: 1.5rem; border-radius: 8px; }
.imc-number { font-size: 2.5rem; font-weight: bold; color: var(--primary); margin: 0.5rem 0; }

/* Chat */
.chat-box {
    height: 300px; overflow-y: auto; border: 1px solid var(--border);
    padding: 1rem; border-radius: 4px; margin-bottom: 1rem; background: #fafafa;
    display: flex; flex-direction: column; gap: 0.5rem;
}
.msg { padding: 0.5rem 1rem; border-radius: 12px; max-width: 80%; }
.msg.me { background: var(--primary); color: white; align-self: flex-end; }
.msg.them { background: #e9ecef; color: var(--text); align-self: flex-start; }
.chat-input { display: flex; gap: 0.5rem; }
.chat-input input { margin-bottom: 0; }