/* RESET */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Inter', 'Segoe UI', sans-serif;
}

body {
    background: #f5f7fb;
    color: #1e293b;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* HEADER */
header {
    text-align: center;
    padding: 50px 20px 30px;
}

header h1 {
    font-size: 34px;
    font-weight: 700;
    background: linear-gradient(90deg, #6366f1, #0ea5e9);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

header p {
    margin-top: 8px;
    color: #64748b;
}

/* MAIN */
main {
    flex: 1;
    width: 90%;
    max-width: 1100px;
    margin: auto;
}

/* SECTION */
section {
    margin-bottom: 60px;
}

section h2 {
    margin-bottom: 25px;
    font-size: 22px;
    font-weight: 600;
}

/* CARD CHUNG */
.card, .week-card, .profile-card {
    background: #ffffff;
    padding: 25px;
    border-radius: 18px;
    box-shadow: 0 8px 25px rgba(0,0,0,0.05);
    transition: all 0.3s ease;
}

/* HIGHLIGHT SINH VIÊN */
.highlight {
    border: 2px solid #6366f1;
}

/* BUTTON */
.btn {
    display: inline-block;
    margin-top: 15px;
    padding: 10px 18px;
    background: linear-gradient(90deg, #6366f1, #0ea5e9);
    color: white;
    border-radius: 10px;
    text-decoration: none;
    font-weight: 500;
    transition: 0.3s;
}

.btn:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 20px rgba(99,102,241,0.3);
}

/* WEEKS GRID */
.week-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(230px, 1fr));
    gap: 25px;
}

.week-card {
    text-decoration: none;
    color: #1e293b;
}

.week-card:hover {
    transform: translateY(-6px);
    box-shadow: 0 15px 35px rgba(0,0,0,0.08);
}

/* ABOUT PAGE */
.about-container {
    display: flex;
    justify-content: center;
}

.profile-card {
    display: flex;
    gap: 40px;
    align-items: center;
}

.profile-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 15px 35px rgba(0,0,0,0.08);
}

.avatar {
    font-size: 70px;
}

.profile-info h2 {
    margin-bottom: 12px;
}

/* FOOTER */
footer {
    text-align: center;
    padding: 25px;
    background: #ffffff;
    border-top: 1px solid #e2e8f0;
    color: #64748b;
    font-size: 14px;
}