/* CSS Reset and Variables for iCal */
:root {
    --primary-color: #667eea;
    --secondary-color: #764ba2;
    --accent-color: #f093fb;
    --text-dark: #2d3748;
    --text-light: #718096;
    --white: #ffffff;
    --light-bg: #f7fafc;
    --card-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --border-radius: 12px;
    --font-primary: 'Inter', 'Nunito', sans-serif;
}

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

body {
    font-family: var(--font-primary);
    line-height: 1.6;
    color: var(--text-dark);
    overflow-x: hidden;
}

html {
    scroll-behavior: smooth;
}

.container {
    padding: 1rem 0;
}

footer {
    margin-bottom: 1rem;
}

/*--------- Intro Sections ---------*/

.intro {
    padding: 5rem 0 2rem 0;
    background: var(--light-bg);
    position: relative;
}

.intro::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 100px;
    background: linear-gradient(180deg, var(--white) 0%, var(--light-bg) 100%);
}

.intro h1 {
    font-size: clamp(2rem, 4vw, 3rem);
    font-weight: 700;
    margin-bottom: 1rem;
    background: linear-gradient(45deg, var(--primary-color), var(--secondary-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    text-align: center;
}

.intro p {
    text-align: center;
    color: var(--text-light);
    font-size: 1.1rem;
}

/*--------- Alert Styles ---------*/

.alert-warning {
    margin-top: 1rem;
    margin-bottom: 0;
    padding: 12px 16px;
    background-color: #fff3cd;
    border: 1px solid #ffeaa7;
    color: #856404;
    border-radius: var(--border-radius);
}

/*--------- Tab Navigation ---------*/

.nav-tabs {
    margin-top: 1rem;
    margin-bottom: 0;
    border-bottom: 1px solid #e2e8f0;
    list-style: none;
    display: flex;
}

.nav-tabs > li {
    margin-bottom: -1px;
}

.nav-tabs > li.active > a,
.nav-tabs > li.active > a:hover,
.nav-tabs > li.active > a:focus {
    color: var(--primary-color);
    background-color: var(--white);
    border: 1px solid #e2e8f0;
    border-bottom-color: transparent;
    cursor: default;
}

.nav-tabs > li > a {
    margin-right: 2px;
    line-height: 1.42857143;
    border: 1px solid transparent;
    border-radius: var(--border-radius) var(--border-radius) 0 0;
    color: var(--text-light);
    padding: 10px 15px;
    text-decoration: none;
    display: block;
}

.nav-tabs > li > a:hover {
    border-color: #e2e8f0 #e2e8f0 #e2e8f0;
    color: var(--primary-color);
    text-decoration: none;
}

.tab-content {
    border-left: 1px solid #e2e8f0;
    border-right: 1px solid #e2e8f0;
    border-bottom: 1px solid #e2e8f0;
    padding: 20px;
    border-radius: 0 0 var(--border-radius) var(--border-radius);
    background: var(--white);
}

.tab-pane {
    display: none;
}

.tab-pane.active {
    display: block;
}

/*--------- Panel Styles ---------*/

.panel {
    margin-bottom: 20px;
    background-color: var(--white);
    border: 1px solid #bee5eb;
    border-radius: var(--border-radius);
    box-shadow: var(--card-shadow);
}

.panel-heading {
    padding: 10px 15px;
    border-bottom: 1px solid #bee5eb;
    border-top-left-radius: calc(var(--border-radius) - 1px);
    border-top-right-radius: calc(var(--border-radius) - 1px);
    font-weight: 600;
    font-size: 1.1rem;
    color: #0c5460;
    background-color: #d1ecf1;
}

.panel-body {
    padding: 15px;
    overflow: auto;
}

/*--------- Button Styles ---------*/

.btn {
    display: inline-block;
    padding: 6px 12px;
    margin: 2px;
    font-size: 14px;
    font-weight: 400;
    line-height: 1.42857143;
    text-align: center;
    white-space: nowrap;
    vertical-align: middle;
    cursor: pointer;
    background-image: none;
    border: 1px solid #ccc;
    border-radius: var(--border-radius);
    text-decoration: none;
    color: #333;
    background-color: var(--white);
}

.btn:hover,
.btn:focus {
    color: #333;
    background-color: #e6e6e6;
    border-color: #adadad;
    text-decoration: none;
}

.btn:active {
    color: #333;
    background-color: #e6e6e6;
    border-color: #adadad;
}

/*--------- Media Object for App Section ---------*/

.media {
    margin-top: 15px;
    display: flex;
    align-items: flex-start;
}

.media-left {
    padding-right: 10px;
}

.media-body {
    flex: 1;
}

.media-heading {
    margin-top: 0;
    margin-bottom: 5px;
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--text-dark);
}

/*--------- Responsive Design ---------*/

@media (max-width: 1200px) {
    .feature-content {
        width: 100%;
        text-align: center;
    }
    
    .feature-icon {
        display: block;
        margin: 10px auto;
    }
}

@media (max-width: 768px) {
    .intro h1 {
        font-size: 2rem;
    }
    
    .intro p {
        font-size: 1rem;
        padding: 0 1rem;
    }
    
    .nav-tabs {
        display: flex;
        flex-wrap: wrap;
    }
    
    .nav-tabs > li {
        flex: 1;
        text-align: center;
    }
    
    .panel-heading {
        font-size: 1rem;
        padding: 8px 12px;
    }
    
    .btn {
        padding: 8px 16px;
        font-size: 12px;
        margin: 3px;
    }
    
    footer li {
        display: block;
        text-align: left;
        padding: 20px 0;
        border-bottom: dashed 1px #c7cacc;
        margin-right: 0 !important;
        float: none;
    }
    
    .media {
        flex-direction: column;
        text-align: center;
    }
    
    .media-left {
        padding-right: 0;
        padding-bottom: 10px;
    }
}

@media (max-width: 480px) {
    .intro h1 {
        font-size: 1.8rem;
    }
    
    .tab-content {
        padding: 15px;
    }
    
    .panel-body {
        padding: 12px;
    }
    
    .btn {
        padding: 6px 12px;
        font-size: 11px;
        margin: 2px;
        display: inline-block;
        width: auto;
        min-width: 80px;
    }
}