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

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
  background: linear-gradient(160deg, #2c5f5f 0%, #3d8080 100%);
  min-height: 100vh;
  padding: 16px 16px 100px;
}

/* ============================================================
TOOLTIP SYSTEM — matches teacher dashboard style
Add data-tooltip="text" and optionally data-tooltip-pos="bottom|left|right"
============================================================ */
[data-tooltip] {
    position: relative;
}

[data-tooltip]::after {
    content: attr(data-tooltip);
    position: absolute;
    bottom: calc(100% + 8px);
    left: 50%;
    transform: translateX(-50%) translateY(4px);
    background: rgba(20, 40, 40, 0.92);
    color: #ffffff;
    font-size: 11px;
    font-weight: 500;
    line-height: 1.4;
    padding: 6px 10px;
    border-radius: 6px;
    pointer-events: none;
    opacity: 0;
    transition: opacity 0.18s ease, transform 0.18s ease;
    z-index: 9999;
    box-shadow: 0 2px 8px rgba(0,0,0,0.25);
    max-width: 220px;
    white-space: normal;
    text-align: center;
}

[data-tooltip]::before {
    content: '';
    position: absolute;
    bottom: calc(100% + 3px);
    left: 50%;
    transform: translateX(-50%);
    border: 5px solid transparent;
    border-top-color: rgba(20, 40, 40, 0.92);
    pointer-events: none;
    opacity: 0;
    transition: opacity 0.18s ease;
    z-index: 9999;
}

[data-tooltip]:hover::after,
[data-tooltip]:hover::before {
    opacity: 1;
    transform: translateX(-50%) translateY(0);
}

/* Bottom */
[data-tooltip][data-tooltip-pos="bottom"]::after {
    bottom: auto;
    top: calc(100% + 8px);
    transform: translateX(-50%) translateY(-4px);
}
[data-tooltip][data-tooltip-pos="bottom"]::before {
    bottom: auto;
    top: calc(100% + 3px);
    border-top-color: transparent;
    border-bottom-color: rgba(20, 40, 40, 0.92);
}
[data-tooltip][data-tooltip-pos="bottom"]:hover::after {
    transform: translateX(-50%) translateY(0);
}

/* Right */
[data-tooltip][data-tooltip-pos="right"]::after {
    bottom: auto;
    top: 50%;
    left: calc(100% + 8px);
    transform: translateY(-50%) translateX(-4px);
}
[data-tooltip][data-tooltip-pos="right"]::before {
    bottom: auto;
    top: 50%;
    left: calc(100% + 3px);
    transform: translateY(-50%);
    border-top-color: transparent;
    border-right-color: rgba(20, 40, 40, 0.92);
}
[data-tooltip][data-tooltip-pos="right"]:hover::after {
    transform: translateY(-50%) translateX(0);
}

/* Left */
[data-tooltip][data-tooltip-pos="left"]::after {
    bottom: auto;
    top: 50%;
    left: auto;
    right: calc(100% + 8px);
    transform: translateY(-50%) translateX(4px);
}
[data-tooltip][data-tooltip-pos="left"]::before {
    bottom: auto;
    top: 50%;
    left: auto;
    right: calc(100% + 3px);
    transform: translateY(-50%);
    border-top-color: transparent;
    border-left-color: rgba(20, 40, 40, 0.92);
}
[data-tooltip][data-tooltip-pos="left"]:hover::after {
    transform: translateY(-50%) translateX(0);
}