/* ==========================================================================
   FPGA TANG NANO 9K - MODERN TECH-FRESH & VIBRANT UI DESIGN SYSTEM
   Bright, Student-Friendly Palette for Electrical & Electronics Engineering
   ========================================================================== */

:root {
    /* Main Backgrounds - Clean, Bright, Tech-Fresh */
    --bg-main: #f8fafc;
    --bg-card: #ffffff;
    --bg-card-hover: #f1f5f9;
    --bg-input: #ffffff;
    --border-color: #e2e8f0;
    --border-active: #2563eb;

    /* Typography Colors - High Contrast Slate */
    --text-main: #0f172a;
    --text-muted: #475569;
    --text-subtle: #64748b;

    /* Accent & Brand Colors */
    --accent-blue: #2563eb;
    --accent-cyan: #0d9488;
    --accent-green: #059669;
    --accent-amber: #d97706;
    --accent-red: #dc2626;
    --accent-purple: #7c3aed;

    /* Shadows & Border Radius */
    --shadow-sm: 0 1px 3px rgba(15, 23, 42, 0.08);
    --shadow-md: 0 4px 16px -2px rgba(15, 23, 42, 0.08), 0 2px 6px -1px rgba(15, 23, 42, 0.04);
    --shadow-lg: 0 12px 30px -4px rgba(37, 99, 235, 0.12), 0 4px 10px -2px rgba(15, 23, 42, 0.04);
    --shadow-glow: 0 0 20px rgba(37, 99, 235, 0.25);
    
    --radius-lg: 14px;
    --radius-md: 10px;
    --radius-sm: 6px;
}

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

body {
    font-family: 'Inter', system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    background-color: var(--bg-main);
    background-image: 
        radial-gradient(at 0% 0%, rgba(37, 99, 235, 0.07) 0px, transparent 50%),
        radial-gradient(at 100% 0%, rgba(13, 148, 136, 0.06) 0px, transparent 50%),
        radial-gradient(at 50% 100%, rgba(245, 158, 11, 0.04) 0px, transparent 50%);
    color: var(--text-main);
    line-height: 1.5;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* ----------------------------------------------------
   MODAL DIALOGS (Login & Teacher PIN)
   ---------------------------------------------------- */
.modal-overlay {
    position: fixed;
    top: 0; left: 0; right: 0; bottom: 0;
    background: rgba(15, 23, 42, 0.65);
    backdrop-filter: blur(8px);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 999;
}

.modal-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 2.5rem;
    width: 100%;
    max-width: 480px;
    box-shadow: 0 25px 50px -12px rgba(15, 23, 42, 0.25);
    text-align: center;
}

.modal-header h2 {
    font-size: 1.75rem;
    font-weight: 800;
    color: var(--text-main);
    margin-bottom: 0.25rem;
    letter-spacing: -0.02em;
}

.modal-header p {
    color: var(--text-muted);
    font-size: 0.9rem;
}

.form-group {
    text-align: left;
    margin-bottom: 1.25rem;
}

.form-group label {
    display: block;
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--text-muted);
    margin-bottom: 0.4rem;
}

.form-control {
    width: 100%;
    padding: 0.75rem 1rem;
    background: var(--bg-input);
    border: 1.5px solid var(--border-color);
    border-radius: var(--radius-md);
    color: var(--text-main);
    font-size: 0.95rem;
    transition: all 0.2s;
}

.form-control:focus {
    outline: none;
    border-color: var(--accent-blue);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.15);
}

.btn-primary {
    padding: 0.75rem 1.25rem;
    background: linear-gradient(135deg, #2563eb, #0284c7);
    border: none;
    border-radius: var(--radius-md);
    color: #ffffff;
    font-weight: 600;
    font-size: 0.9rem;
    cursor: pointer;
    box-shadow: 0 4px 14px rgba(37, 99, 235, 0.3);
    transition: all 0.2s;
}

.btn-primary:hover {
    transform: translateY(-1.5px);
    box-shadow: 0 8px 20px rgba(37, 99, 235, 0.4);
}

.btn-reset-lab {
    background: #fef2f2;
    border: 1px solid #fca5a5;
    color: #dc2626;
    padding: 0.35rem 0.75rem;
    border-radius: var(--radius-sm);
    font-size: 0.75rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s;
}

.btn-reset-lab:hover {
    background: #fee2e2;
    color: #b91c1c;
}

/* ----------------------------------------------------
   APP HEADER & NAVIGATION BAR
   ---------------------------------------------------- */
.app-header {
    background: rgba(255, 255, 255, 0.92);
    border-bottom: 1px solid var(--border-color);
    backdrop-filter: blur(12px);
    position: sticky;
    top: 0;
    z-index: 100;
    padding: 0.75rem 2rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    box-shadow: var(--shadow-sm);
}

.brand-container {
    display: flex;
    align-items: center;
    gap: 12px;
}

.brand-logo {
    width: 40px;
    height: 40px;
    background: linear-gradient(135deg, #2563eb, #0d9488);
    border-radius: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 800;
    font-size: 1.1rem;
    color: #ffffff;
    box-shadow: 0 4px 12px rgba(37, 99, 235, 0.25);
}

.brand-title h1 {
    font-size: 1.1rem;
    font-weight: 800;
    color: var(--text-main);
    letter-spacing: -0.01em;
}

.brand-title p {
    font-size: 0.75rem;
    color: var(--accent-cyan);
    font-weight: 600;
}

.nav-tabs {
    display: flex;
    gap: 6px;
    background: #f1f5f9;
    padding: 5px;
    border-radius: 30px;
    border: 1px solid #e2e8f0;
}

.nav-tab {
    padding: 0.5rem 1.1rem;
    border-radius: 20px;
    color: var(--text-muted);
    font-size: 0.85rem;
    font-weight: 600;
    background: transparent;
    border: none;
    cursor: pointer;
    transition: all 0.2s;
}

.nav-tab:hover {
    color: var(--text-main);
    background: rgba(255, 255, 255, 0.8);
}

.nav-tab.active {
    color: #ffffff;
    background: linear-gradient(135deg, #2563eb, #3b82f6);
    box-shadow: 0 4px 12px rgba(37, 99, 235, 0.35);
}

.user-profile {
    display: flex;
    align-items: center;
    gap: 12px;
    background: #ffffff;
    padding: 5px 14px;
    border-radius: 20px;
    border: 1px solid #e2e8f0;
    box-shadow: var(--shadow-sm);
}

.user-avatar {
    width: 30px; height: 30px;
    border-radius: 50%;
    background: linear-gradient(135deg, #10b981, #059669);
    color: #ffffff;
    display: flex; align-items: center; justify-content: center;
    font-weight: 700; font-size: 0.8rem;
}

.user-details {
    font-size: 0.8rem;
}

.user-details strong { display: block; color: var(--text-main); font-weight: 700; }
.user-details span { color: var(--text-subtle); }

.btn-logout {
    background: transparent; border: none; color: var(--accent-red);
    font-size: 0.75rem; cursor: pointer; text-decoration: underline; margin-left: 6px; font-weight: 600;
}

/* ----------------------------------------------------
   MAIN WORKSPACE & LAYOUT
   ---------------------------------------------------- */
.main-container {
    flex: 1;
    padding: 1.5rem 2rem;
    max-width: 1750px;
    margin: 0 auto;
    width: 100%;
}

.tab-content {
    display: none;
}

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

/* 3-Column Workspace Layout */
.workspace-layout {
    display: grid;
    grid-template-columns: 290px 1fr 450px;
    gap: 1.25rem;
    min-height: 720px;
}

.ws-sidebar {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    display: flex;
    flex-direction: column;
    overflow: hidden;
    box-shadow: var(--shadow-md);
}

.ws-sidebar-header {
    background: #f8fafc;
    padding: 0.85rem 1.1rem;
    border-bottom: 1px solid var(--border-color);
    font-size: 0.875rem;
    font-weight: 700;
    color: var(--text-main);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.ws-lab-list {
    flex: 1;
    overflow-y: auto;
    padding: 0.6rem;
    max-height: calc(100vh - 180px);
}

.ws-lab-item {
    padding: 0.7rem 0.9rem;
    border-radius: var(--radius-md);
    margin-bottom: 0.4rem;
    cursor: pointer;
    border: 1px solid transparent;
    transition: all 0.18s;
    font-size: 0.825rem;
    background: #ffffff;
}

.ws-lab-item:hover {
    background: #f1f5f9;
    border-color: #cbd5e1;
}

.ws-lab-item.active {
    background: #eff6ff;
    border-color: var(--accent-blue);
    box-shadow: 0 2px 8px rgba(37, 99, 235, 0.12);
}

.ws-lab-item-title {
    color: var(--text-main);
    font-weight: 600;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.ws-lab-item-sub {
    font-size: 0.725rem;
    color: var(--text-subtle);
    display: flex;
    justify-content: space-between;
    margin-top: 3px;
}

/* Middle Editor & Details Pane */
.editor-pane {
    display: flex;
    flex-direction: column;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    overflow: hidden;
    box-shadow: var(--shadow-md);
}

.pane-header {
    background: #1e293b;
    padding: 0.85rem 1.25rem;
    border-bottom: 1px solid #334155;
    display: flex; justify-content: space-between; align-items: center;
}

.pane-title { font-size: 0.925rem; font-weight: 700; color: #ffffff; display: flex; align-items: center; gap: 8px; }

/* Code Editor IDE Wrapper with Syntax Highlighting Overlay */
.code-editor-wrapper {
    position: relative;
    flex: 1;
    min-height: 360px;
    background: #0f172a;
    border-top: 1px solid #334155;
    border-bottom: 1px solid #334155;
    overflow: hidden;
}

.code-highlight-bg,
.editor-textarea {
    position: absolute !important;
    top: 0 !important;
    left: 0 !important;
    right: 0 !important;
    bottom: 0 !important;
    width: 100% !important;
    height: 100% !important;
    margin: 0 !important;
    padding: 1rem !important;
    border: 0 !important;
    outline: none !important;
    box-sizing: border-box !important;
    font-family: 'Fira Code', 'Consolas', 'Courier New', monospace !important;
    font-size: 13.5px !important;
    line-height: 20px !important;
    letter-spacing: 0px !important;
    word-spacing: 0px !important;
    tab-size: 4 !important;
    -moz-tab-size: 4 !important;
    white-space: pre !important;
    word-wrap: normal !important;
    overflow-wrap: normal !important;
    text-align: left !important;
    vertical-align: top !important;
}

.code-highlight-bg {
    z-index: 1;
    pointer-events: none;
    background: transparent !important;
    color: #e2e8f0;
    overflow: hidden !important;
}

.code-highlight-bg code {
    margin: 0 !important;
    padding: 0 !important;
    border: 0 !important;
    background: transparent !important;
    font-family: inherit !important;
    font-size: inherit !important;
    line-height: inherit !important;
    letter-spacing: inherit !important;
    word-spacing: inherit !important;
    white-space: inherit !important;
    display: inline !important;
    vertical-align: top !important;
}

.editor-textarea {
    z-index: 2;
    background: transparent !important;
    color: transparent !important;
    caret-color: #38bdf8;
    resize: none;
    overflow: auto !important;
}

.editor-textarea::selection {
    background: rgba(56, 189, 248, 0.35) !important;
    color: transparent !important;
}

/* Verilog Syntax Highlighting Colors */
.hl-keyword { color: #ff7b72; font-weight: 700; }
.hl-comment { color: #8b949e; font-style: italic; }
.hl-string { color: #a5d6ff; }
.hl-directive { color: #d2a8ff; font-weight: 600; }
.hl-system { color: #79c0ff; font-weight: 600; }
.hl-number { color: #79c0ff; }
.hl-operator { color: #f0883e; font-weight: 600; }

/* Right Column: Board & GTKWave Simulation Pane */
.board-pane {
    display: flex;
    flex-direction: column;
    gap: 1.25rem;
    overflow-y: auto;
    max-height: calc(100vh - 180px);
}

.hardware-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 1.25rem;
    box-shadow: var(--shadow-md);
}

.board-sim-view {
    background: #0b1329;
    border: 2px solid #1e293b;
    border-radius: var(--radius-md);
    padding: 1.1rem;
}

.led-row {
    display: flex; gap: 14px; justify-content: center; margin-top: 1.1rem; flex-wrap: wrap;
}

.led-indicator {
    width: 34px; height: 34px; border-radius: 50%;
    background: #1e293b; border: 2px solid #475569;
    display: flex; align-items: center; justify-content: center;
    font-size: 0.75rem; font-weight: 700; color: #94a3b8;
    transition: all 0.2s;
}

.led-indicator.on {
    background: #ef4444; border-color: #f87171;
    box-shadow: 0 0 18px rgba(239, 68, 68, 0.95); color: #ffffff;
}

.sw-row {
    display: flex; gap: 8px; flex-wrap: wrap; margin-top: 0.85rem;
}

.btn-hw-switch {
    padding: 0.45rem 0.85rem;
    background: #ffffff;
    border: 1.5px solid #cbd5e1;
    border-radius: var(--radius-md);
    color: var(--text-main); font-size: 0.8rem; font-weight: 600;
    cursor: pointer; transition: all 0.18s;
}

.btn-hw-switch:hover {
    border-color: var(--accent-blue);
    background: #f8fafc;
}

.btn-hw-switch.active {
    background: #2563eb;
    border-color: #2563eb;
    color: #ffffff;
    box-shadow: 0 4px 12px rgba(37, 99, 235, 0.35);
}

/* ----------------------------------------------------
   TUTORIALS TAB (TUTORIALS 1, 2, 3)
   ---------------------------------------------------- */
.tut-grid {
    display: grid;
    grid-template-columns: 300px 1fr;
    gap: 1.5rem;
}

.tut-sidebar {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 1.1rem;
    height: fit-content;
    box-shadow: var(--shadow-md);
}

.tut-nav-item {
    padding: 0.9rem 1.1rem;
    border-radius: var(--radius-md);
    margin-bottom: 0.5rem;
    cursor: pointer;
    border: 1.5px solid transparent;
    transition: all 0.2s;
    background: #f8fafc;
}

.tut-nav-item:hover {
    background: #f1f5f9;
    border-color: #cbd5e1;
}

.tut-nav-item.active {
    background: #eff6ff;
    border-color: var(--accent-blue);
    box-shadow: 0 4px 12px rgba(37, 99, 235, 0.12);
}

.tut-nav-title { font-weight: 700; font-size: 0.9rem; color: var(--text-main); }
.tut-nav-sub { font-size: 0.75rem; color: var(--text-subtle); margin-top: 2px; }

.tut-body {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 2.25rem;
    box-shadow: var(--shadow-md);
}

.tut-article h2 {
    font-size: 1.6rem; font-weight: 800; color: var(--text-main); margin-bottom: 0.5rem;
    border-bottom: 2.5px solid var(--accent-blue); padding-bottom: 0.5rem; letter-spacing: -0.01em;
}

.tut-article .subtitle { color: var(--accent-cyan); font-size: 0.95rem; font-weight: 600; margin-bottom: 1.5rem; }
.tut-section { margin-bottom: 2rem; }
.tut-section h3 { font-size: 1.2rem; font-weight: 700; color: var(--text-main); margin-bottom: 0.75rem; }
.tut-section p { font-size: 0.95rem; color: var(--text-muted); margin-bottom: 0.75rem; line-height: 1.6; }

/* ----------------------------------------------------
   EXERCISES OVERVIEW GRID TAB
   ---------------------------------------------------- */
.filter-bar {
    display: flex; justify-content: space-between; align-items: center;
    margin-bottom: 1.5rem; background: var(--bg-card); padding: 1.1rem 1.6rem;
    border-radius: var(--radius-lg); border: 1px solid var(--border-color);
    box-shadow: var(--shadow-md);
}

.filter-group { display: flex; gap: 8px; flex-wrap: wrap; }

.btn-filter {
    padding: 0.45rem 1rem; border-radius: 20px; background: #f1f5f9;
    border: 1px solid #cbd5e1; color: var(--text-muted); font-size: 0.8rem; font-weight: 600; cursor: pointer;
    transition: all 0.2s;
}

.btn-filter:hover {
    background: #e2e8f0; color: var(--text-main);
}

.btn-filter.active {
    background: var(--accent-blue); color: #ffffff; border-color: var(--accent-blue);
    box-shadow: 0 4px 12px rgba(37, 99, 235, 0.3);
}

.ex-cards-grid {
    display: grid; grid-template-columns: repeat(auto-fill, minmax(340px, 1fr)); gap: 1.25rem;
}

.ex-card {
    background: var(--bg-card); border: 1px solid var(--border-color); border-radius: var(--radius-lg);
    padding: 1.35rem; display: flex; flex-direction: column; justify-content: space-between;
    transition: all 0.25s; cursor: pointer; box-shadow: var(--shadow-md);
}

.ex-card:hover {
    transform: translateY(-4px); border-color: var(--accent-blue); box-shadow: var(--shadow-lg);
}

.ex-card-header {
    display: flex; justify-content: space-between; align-items: flex-start; margin-bottom: 0.75rem;
}

.badge {
    padding: 3px 10px; border-radius: 12px; font-size: 0.7rem; font-weight: 700; text-transform: uppercase; letter-spacing: 0.03em;
}

.badge-easy { background: #ecfdf5; color: #047857; border: 1px solid #a7f3d0; }
.badge-medium { background: #fffbeb; color: #b45309; border: 1px solid #fde68a; }
.badge-hard { background: #fef2f2; color: #b91c1c; border: 1px solid #fca5a5; }

.ex-card-title {
    font-size: 1.05rem; font-weight: 800; color: var(--text-main); margin-bottom: 0.4rem; letter-spacing: -0.01em;
}

.ex-card-desc {
    font-size: 0.835rem; color: var(--text-muted); margin-bottom: 1rem;
    display: -webkit-box; -webkit-line-clamp: 3; -webkit-box-orient: vertical; overflow: hidden; line-height: 1.5;
}

.ex-card-footer {
    display: flex; justify-content: space-between; align-items: center;
    border-top: 1px solid var(--border-color); padding-top: 0.85rem; margin-top: auto; gap: 8px;
}

.status-indicator { font-size: 0.775rem; color: var(--text-subtle); display: flex; align-items: center; gap: 4px; font-weight: 500; }
.status-indicator.done { color: var(--accent-green); font-weight: 700; }

/* ----------------------------------------------------
   WAVEFORM & DATA TABLES
   ---------------------------------------------------- */
.waveform-box {
    background: #090d16; border: 1px solid #1e293b; border-radius: var(--radius-md);
    padding: 0.85rem; font-family: monospace;
}

.waveform-header {
    display: flex; justify-content: space-between; font-size: 0.75rem; color: #94a3b8; margin-bottom: 0.5rem; font-weight: 600;
}

.wave-row { display: flex; align-items: center; gap: 10px; margin-bottom: 5px; }
.wave-label { width: 120px; font-size: 0.75rem; font-weight: 600; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.wave-canvas { flex: 1; height: 26px; }
.wave-canvas svg { width: 100%; height: 100%; }

/* Data Tables */
.data-table { width: 100%; border-collapse: collapse; margin: 1rem 0; font-size: 0.85rem; }
.data-table th, .data-table td { padding: 0.65rem 0.85rem; border: 1px solid var(--border-color); text-align: left; }
.data-table th { background: #f8fafc; color: var(--text-main); font-weight: 700; }

.code-block-header {
    background: #1e293b; padding: 0.45rem 0.85rem; font-size: 0.8rem; font-weight: 700; color: #38bdf8;
    border-radius: var(--radius-sm) var(--radius-sm) 0 0; margin-top: 1rem;
}

pre code {
    display: block; background: #0f172a; padding: 1rem; font-family: monospace; font-size: 0.85rem; color: #38bdf8;
    border-radius: 0 0 var(--radius-sm) var(--radius-sm); overflow-x: auto;
}

.tip-box {
    background: #eff6ff; border-left: 4px solid var(--accent-blue); padding: 1rem; border-radius: 0 var(--radius-md) var(--radius-md) 0; margin: 1rem 0; font-size: 0.9rem; color: #1e40af; font-weight: 500;
}

/* ==========================================================================
   PRINTABLE PDF REPORT STYLES (@media print)
   ========================================================================== */
.print-only { display: none; }

@media print {
    .no-print { display: none !important; }
    .print-only { display: block !important; }

    body { background: #ffffff !important; color: #0f172a !important; font-family: 'Times New Roman', Times, serif; font-size: 11pt; }
    .report-page { width: 100%; max-width: 800px; margin: 0 auto; padding: 20px; }
    .report-header { text-align: center; border-bottom: 2px solid #1e3a8a; padding-bottom: 10px; margin-bottom: 20px; }
    .report-header h1 { font-size: 18pt; color: #1e3a8a; text-transform: uppercase; margin-bottom: 4px; font-weight: bold; }
    .report-header h2 { font-size: 14pt; color: #1e40af; margin-bottom: 8px; }

    .report-info-grid {
        display: grid; grid-template-columns: 1fr 1fr; gap: 10px; background: #f8fafc;
        border: 1px solid #cbd5e1; padding: 12px 16px; border-radius: 4px; margin-bottom: 20px;
    }

    .report-table { width: 100%; border-collapse: collapse; margin: 15px 0; }
    .report-table th, .report-table td { border: 1px solid #94a3b8; padding: 6px 8px; font-size: 9.5pt; }
    .report-table th { background: #e2e8f0; color: #0f172a; font-weight: bold; }

    .report-code-box {
        background: #f1f5f9; border: 1px solid #cbd5e1; font-family: monospace; font-size: 9pt;
        padding: 8px 12px; margin: 6px 0 15px 0; white-space: pre-wrap;
    }
}